diff options
Diffstat (limited to 'Documentation')
45 files changed, 2330 insertions, 723 deletions
diff --git a/Documentation/ABI/testing/sysfs-ata b/Documentation/ABI/testing/sysfs-ata new file mode 100644 index 00000000000..0a932155cbb --- /dev/null +++ b/Documentation/ABI/testing/sysfs-ata | |||
@@ -0,0 +1,99 @@ | |||
1 | What: /sys/class/ata_... | ||
2 | Date: August 2008 | ||
3 | Contact: Gwendal Grignou<gwendal@google.com> | ||
4 | Description: | ||
5 | |||
6 | Provide a place in sysfs for storing the ATA topology of the system. This allows | ||
7 | retrieving various information about ATA objects. | ||
8 | |||
9 | Files under /sys/class/ata_port | ||
10 | ------------------------------- | ||
11 | |||
12 | For each port, a directory ataX is created where X is the ata_port_id of | ||
13 | the port. The device parent is the ata host device. | ||
14 | |||
15 | idle_irq (read) | ||
16 | |||
17 | Number of IRQ received by the port while idle [some ata HBA only]. | ||
18 | |||
19 | nr_pmp_links (read) | ||
20 | |||
21 | If a SATA Port Multiplier (PM) is connected, number of link behind it. | ||
22 | |||
23 | Files under /sys/class/ata_link | ||
24 | ------------------------------- | ||
25 | |||
26 | Behind each port, there is a ata_link. If there is a SATA PM in the | ||
27 | topology, 15 ata_link objects are created. | ||
28 | |||
29 | If a link is behind a port, the directory name is linkX, where X is | ||
30 | ata_port_id of the port. | ||
31 | If a link is behind a PM, its name is linkX.Y where X is ata_port_id | ||
32 | of the parent port and Y the PM port. | ||
33 | |||
34 | hw_sata_spd_limit | ||
35 | |||
36 | Maximum speed supported by the connected SATA device. | ||
37 | |||
38 | sata_spd_limit | ||
39 | |||
40 | Maximum speed imposed by libata. | ||
41 | |||
42 | sata_spd | ||
43 | |||
44 | Current speed of the link [1.5, 3Gps,...]. | ||
45 | |||
46 | Files under /sys/class/ata_device | ||
47 | --------------------------------- | ||
48 | |||
49 | Behind each link, up to two ata device are created. | ||
50 | The name of the directory is devX[.Y].Z where: | ||
51 | - X is ata_port_id of the port where the device is connected, | ||
52 | - Y the port of the PM if any, and | ||
53 | - Z the device id: for PATA, there is usually 2 devices [0,1], | ||
54 | only 1 for SATA. | ||
55 | |||
56 | class | ||
57 | Device class. Can be "ata" for disk, "atapi" for packet device, | ||
58 | "pmp" for PM, or "none" if no device was found behind the link. | ||
59 | |||
60 | dma_mode | ||
61 | |||
62 | Transfer modes supported by the device when in DMA mode. | ||
63 | Mostly used by PATA device. | ||
64 | |||
65 | pio_mode | ||
66 | |||
67 | Transfer modes supported by the device when in PIO mode. | ||
68 | Mostly used by PATA device. | ||
69 | |||
70 | xfer_mode | ||
71 | |||
72 | Current transfer mode. | ||
73 | |||
74 | id | ||
75 | |||
76 | Cached result of IDENTIFY command, as described in ATA8 7.16 and 7.17. | ||
77 | Only valid if the device is not a PM. | ||
78 | |||
79 | gscr | ||
80 | |||
81 | Cached result of the dump of PM GSCR register. | ||
82 | Valid registers are: | ||
83 | 0: SATA_PMP_GSCR_PROD_ID, | ||
84 | 1: SATA_PMP_GSCR_REV, | ||
85 | 2: SATA_PMP_GSCR_PORT_INFO, | ||
86 | 32: SATA_PMP_GSCR_ERROR, | ||
87 | 33: SATA_PMP_GSCR_ERROR_EN, | ||
88 | 64: SATA_PMP_GSCR_FEAT, | ||
89 | 96: SATA_PMP_GSCR_FEAT_EN, | ||
90 | 130: SATA_PMP_GSCR_SII_GPIO | ||
91 | Only valid if the device is a PM. | ||
92 | |||
93 | spdn_cnt | ||
94 | |||
95 | Number of time libata decided to lower the speed of link due to errors. | ||
96 | |||
97 | ering | ||
98 | |||
99 | Formatted output of the error ring of the device. | ||
diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power index 6123c523bfd..7628cd1bc36 100644 --- a/Documentation/ABI/testing/sysfs-devices-power +++ b/Documentation/ABI/testing/sysfs-devices-power | |||
@@ -77,3 +77,91 @@ Description: | |||
77 | devices this attribute is set to "enabled" by bus type code or | 77 | devices this attribute is set to "enabled" by bus type code or |
78 | device drivers and in that cases it should be safe to leave the | 78 | device drivers and in that cases it should be safe to leave the |
79 | default value. | 79 | default value. |
80 | |||
81 | What: /sys/devices/.../power/wakeup_count | ||
82 | Date: September 2010 | ||
83 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | ||
84 | Description: | ||
85 | The /sys/devices/.../wakeup_count attribute contains the number | ||
86 | of signaled wakeup events associated with the device. This | ||
87 | attribute is read-only. If the device is not enabled to wake up | ||
88 | the system from sleep states, this attribute is empty. | ||
89 | |||
90 | What: /sys/devices/.../power/wakeup_active_count | ||
91 | Date: September 2010 | ||
92 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | ||
93 | Description: | ||
94 | The /sys/devices/.../wakeup_active_count attribute contains the | ||
95 | number of times the processing of wakeup events associated with | ||
96 | the device was completed (at the kernel level). This attribute | ||
97 | is read-only. If the device is not enabled to wake up the | ||
98 | system from sleep states, this attribute is empty. | ||
99 | |||
100 | What: /sys/devices/.../power/wakeup_hit_count | ||
101 | Date: September 2010 | ||
102 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | ||
103 | Description: | ||
104 | The /sys/devices/.../wakeup_hit_count attribute contains the | ||
105 | number of times the processing of a wakeup event associated with | ||
106 | the device might prevent the system from entering a sleep state. | ||
107 | This attribute is read-only. If the device is not enabled to | ||
108 | wake up the system from sleep states, this attribute is empty. | ||
109 | |||
110 | What: /sys/devices/.../power/wakeup_active | ||
111 | Date: September 2010 | ||
112 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | ||
113 | Description: | ||
114 | The /sys/devices/.../wakeup_active attribute contains either 1, | ||
115 | or 0, depending on whether or not a wakeup event associated with | ||
116 | the device is being processed (1). This attribute is read-only. | ||
117 | If the device is not enabled to wake up the system from sleep | ||
118 | states, this attribute is empty. | ||
119 | |||
120 | What: /sys/devices/.../power/wakeup_total_time_ms | ||
121 | Date: September 2010 | ||
122 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | ||
123 | Description: | ||
124 | The /sys/devices/.../wakeup_total_time_ms attribute contains | ||
125 | the total time of processing wakeup events associated with the | ||
126 | device, in milliseconds. This attribute is read-only. If the | ||
127 | device is not enabled to wake up the system from sleep states, | ||
128 | this attribute is empty. | ||
129 | |||
130 | What: /sys/devices/.../power/wakeup_max_time_ms | ||
131 | Date: September 2010 | ||
132 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | ||
133 | Description: | ||
134 | The /sys/devices/.../wakeup_max_time_ms attribute contains | ||
135 | the maximum time of processing a single wakeup event associated | ||
136 | with the device, in milliseconds. This attribute is read-only. | ||
137 | If the device is not enabled to wake up the system from sleep | ||
138 | states, this attribute is empty. | ||
139 | |||
140 | What: /sys/devices/.../power/wakeup_last_time_ms | ||
141 | Date: September 2010 | ||
142 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | ||
143 | Description: | ||
144 | The /sys/devices/.../wakeup_last_time_ms attribute contains | ||
145 | the value of the monotonic clock corresponding to the time of | ||
146 | signaling the last wakeup event associated with the device, in | ||
147 | milliseconds. This attribute is read-only. If the device is | ||
148 | not enabled to wake up the system from sleep states, this | ||
149 | attribute is empty. | ||
150 | |||
151 | What: /sys/devices/.../power/autosuspend_delay_ms | ||
152 | Date: September 2010 | ||
153 | Contact: Alan Stern <stern@rowland.harvard.edu> | ||
154 | Description: | ||
155 | The /sys/devices/.../power/autosuspend_delay_ms attribute | ||
156 | contains the autosuspend delay value (in milliseconds). Some | ||
157 | drivers do not want their device to suspend as soon as it | ||
158 | becomes idle at run time; they want the device to remain | ||
159 | inactive for a certain minimum period of time first. That | ||
160 | period is called the autosuspend delay. Negative values will | ||
161 | prevent the device from being suspended at run time (similar | ||
162 | to writing "on" to the power/control attribute). Values >= | ||
163 | 1000 will cause the autosuspend timer expiration to be rounded | ||
164 | up to the nearest second. | ||
165 | |||
166 | Not all drivers support this attribute. If it isn't supported, | ||
167 | attempts to read or write it will yield I/O errors. | ||
diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power index 2875f1f74a0..194ca446ac2 100644 --- a/Documentation/ABI/testing/sysfs-power +++ b/Documentation/ABI/testing/sysfs-power | |||
@@ -99,9 +99,38 @@ Description: | |||
99 | 99 | ||
100 | dmesg -s 1000000 | grep 'hash matches' | 100 | dmesg -s 1000000 | grep 'hash matches' |
101 | 101 | ||
102 | If you do not get any matches (or they appear to be false | ||
103 | positives), it is possible that the last PM event point | ||
104 | referred to a device created by a loadable kernel module. In | ||
105 | this case cat /sys/power/pm_trace_dev_match (see below) after | ||
106 | your system is started up and the kernel modules are loaded. | ||
107 | |||
102 | CAUTION: Using it will cause your machine's real-time (CMOS) | 108 | CAUTION: Using it will cause your machine's real-time (CMOS) |
103 | clock to be set to a random invalid time after a resume. | 109 | clock to be set to a random invalid time after a resume. |
104 | 110 | ||
111 | What; /sys/power/pm_trace_dev_match | ||
112 | Date: October 2010 | ||
113 | Contact: James Hogan <james@albanarts.com> | ||
114 | Description: | ||
115 | The /sys/power/pm_trace_dev_match file contains the name of the | ||
116 | device associated with the last PM event point saved in the RTC | ||
117 | across reboots when pm_trace has been used. More precisely it | ||
118 | contains the list of current devices (including those | ||
119 | registered by loadable kernel modules since boot) which match | ||
120 | the device hash in the RTC at boot, with a newline after each | ||
121 | one. | ||
122 | |||
123 | The advantage of this file over the hash matches printed to the | ||
124 | kernel log (see /sys/power/pm_trace), is that it includes | ||
125 | devices created after boot by loadable kernel modules. | ||
126 | |||
127 | Due to the small hash size necessary to fit in the RTC, it is | ||
128 | possible that more than one device matches the hash, in which | ||
129 | case further investigation is required to determine which | ||
130 | device is causing the problem. Note that genuine RTC clock | ||
131 | values (such as when pm_trace has not been used), can still | ||
132 | match a device and output it's name here. | ||
133 | |||
105 | What: /sys/power/pm_async | 134 | What: /sys/power/pm_async |
106 | Date: January 2009 | 135 | Date: January 2009 |
107 | Contact: Rafael J. Wysocki <rjw@sisk.pl> | 136 | Contact: Rafael J. Wysocki <rjw@sisk.pl> |
diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl index ecd35e9d441..feca0758391 100644 --- a/Documentation/DocBook/device-drivers.tmpl +++ b/Documentation/DocBook/device-drivers.tmpl | |||
@@ -46,7 +46,6 @@ | |||
46 | 46 | ||
47 | <sect1><title>Atomic and pointer manipulation</title> | 47 | <sect1><title>Atomic and pointer manipulation</title> |
48 | !Iarch/x86/include/asm/atomic.h | 48 | !Iarch/x86/include/asm/atomic.h |
49 | !Iarch/x86/include/asm/unaligned.h | ||
50 | </sect1> | 49 | </sect1> |
51 | 50 | ||
52 | <sect1><title>Delaying, scheduling, and timer routines</title> | 51 | <sect1><title>Delaying, scheduling, and timer routines</title> |
diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index 910c923a9b8..2861055afd7 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl | |||
@@ -136,6 +136,7 @@ | |||
136 | #ifdef CONFIG_COMPAT | 136 | #ifdef CONFIG_COMPAT |
137 | .compat_ioctl = i915_compat_ioctl, | 137 | .compat_ioctl = i915_compat_ioctl, |
138 | #endif | 138 | #endif |
139 | .llseek = noop_llseek, | ||
139 | }, | 140 | }, |
140 | .pci_driver = { | 141 | .pci_driver = { |
141 | .name = DRIVER_NAME, | 142 | .name = DRIVER_NAME, |
diff --git a/Documentation/DocBook/genericirq.tmpl b/Documentation/DocBook/genericirq.tmpl index 1448b33fd22..fb10fd08c05 100644 --- a/Documentation/DocBook/genericirq.tmpl +++ b/Documentation/DocBook/genericirq.tmpl | |||
@@ -28,7 +28,7 @@ | |||
28 | </authorgroup> | 28 | </authorgroup> |
29 | 29 | ||
30 | <copyright> | 30 | <copyright> |
31 | <year>2005-2006</year> | 31 | <year>2005-2010</year> |
32 | <holder>Thomas Gleixner</holder> | 32 | <holder>Thomas Gleixner</holder> |
33 | </copyright> | 33 | </copyright> |
34 | <copyright> | 34 | <copyright> |
@@ -100,6 +100,10 @@ | |||
100 | <listitem><para>Edge type</para></listitem> | 100 | <listitem><para>Edge type</para></listitem> |
101 | <listitem><para>Simple type</para></listitem> | 101 | <listitem><para>Simple type</para></listitem> |
102 | </itemizedlist> | 102 | </itemizedlist> |
103 | During the implementation we identified another type: | ||
104 | <itemizedlist> | ||
105 | <listitem><para>Fast EOI type</para></listitem> | ||
106 | </itemizedlist> | ||
103 | In the SMP world of the __do_IRQ() super-handler another type | 107 | In the SMP world of the __do_IRQ() super-handler another type |
104 | was identified: | 108 | was identified: |
105 | <itemizedlist> | 109 | <itemizedlist> |
@@ -153,6 +157,7 @@ | |||
153 | is still available. This leads to a kind of duality for the time | 157 | is still available. This leads to a kind of duality for the time |
154 | being. Over time the new model should be used in more and more | 158 | being. Over time the new model should be used in more and more |
155 | architectures, as it enables smaller and cleaner IRQ subsystems. | 159 | architectures, as it enables smaller and cleaner IRQ subsystems. |
160 | It's deprecated for three years now and about to be removed. | ||
156 | </para> | 161 | </para> |
157 | </chapter> | 162 | </chapter> |
158 | <chapter id="bugs"> | 163 | <chapter id="bugs"> |
@@ -217,6 +222,7 @@ | |||
217 | <itemizedlist> | 222 | <itemizedlist> |
218 | <listitem><para>handle_level_irq</para></listitem> | 223 | <listitem><para>handle_level_irq</para></listitem> |
219 | <listitem><para>handle_edge_irq</para></listitem> | 224 | <listitem><para>handle_edge_irq</para></listitem> |
225 | <listitem><para>handle_fasteoi_irq</para></listitem> | ||
220 | <listitem><para>handle_simple_irq</para></listitem> | 226 | <listitem><para>handle_simple_irq</para></listitem> |
221 | <listitem><para>handle_percpu_irq</para></listitem> | 227 | <listitem><para>handle_percpu_irq</para></listitem> |
222 | </itemizedlist> | 228 | </itemizedlist> |
@@ -233,33 +239,33 @@ | |||
233 | are used by the default flow implementations. | 239 | are used by the default flow implementations. |
234 | The following helper functions are implemented (simplified excerpt): | 240 | The following helper functions are implemented (simplified excerpt): |
235 | <programlisting> | 241 | <programlisting> |
236 | default_enable(irq) | 242 | default_enable(struct irq_data *data) |
237 | { | 243 | { |
238 | desc->chip->unmask(irq); | 244 | desc->chip->irq_unmask(data); |
239 | } | 245 | } |
240 | 246 | ||
241 | default_disable(irq) | 247 | default_disable(struct irq_data *data) |
242 | { | 248 | { |
243 | if (!delay_disable(irq)) | 249 | if (!delay_disable(data)) |
244 | desc->chip->mask(irq); | 250 | desc->chip->irq_mask(data); |
245 | } | 251 | } |
246 | 252 | ||
247 | default_ack(irq) | 253 | default_ack(struct irq_data *data) |
248 | { | 254 | { |
249 | chip->ack(irq); | 255 | chip->irq_ack(data); |
250 | } | 256 | } |
251 | 257 | ||
252 | default_mask_ack(irq) | 258 | default_mask_ack(struct irq_data *data) |
253 | { | 259 | { |
254 | if (chip->mask_ack) { | 260 | if (chip->irq_mask_ack) { |
255 | chip->mask_ack(irq); | 261 | chip->irq_mask_ack(data); |
256 | } else { | 262 | } else { |
257 | chip->mask(irq); | 263 | chip->irq_mask(data); |
258 | chip->ack(irq); | 264 | chip->irq_ack(data); |
259 | } | 265 | } |
260 | } | 266 | } |
261 | 267 | ||
262 | noop(irq) | 268 | noop(struct irq_data *data)) |
263 | { | 269 | { |
264 | } | 270 | } |
265 | 271 | ||
@@ -278,12 +284,27 @@ noop(irq) | |||
278 | <para> | 284 | <para> |
279 | The following control flow is implemented (simplified excerpt): | 285 | The following control flow is implemented (simplified excerpt): |
280 | <programlisting> | 286 | <programlisting> |
281 | desc->chip->start(); | 287 | desc->chip->irq_mask(); |
282 | handle_IRQ_event(desc->action); | 288 | handle_IRQ_event(desc->action); |
283 | desc->chip->end(); | 289 | desc->chip->irq_unmask(); |
284 | </programlisting> | 290 | </programlisting> |
285 | </para> | 291 | </para> |
286 | </sect3> | 292 | </sect3> |
293 | <sect3 id="Default_FASTEOI_IRQ_flow_handler"> | ||
294 | <title>Default Fast EOI IRQ flow handler</title> | ||
295 | <para> | ||
296 | handle_fasteoi_irq provides a generic implementation | ||
297 | for interrupts, which only need an EOI at the end of | ||
298 | the handler | ||
299 | </para> | ||
300 | <para> | ||
301 | The following control flow is implemented (simplified excerpt): | ||
302 | <programlisting> | ||
303 | handle_IRQ_event(desc->action); | ||
304 | desc->chip->irq_eoi(); | ||
305 | </programlisting> | ||
306 | </para> | ||
307 | </sect3> | ||
287 | <sect3 id="Default_Edge_IRQ_flow_handler"> | 308 | <sect3 id="Default_Edge_IRQ_flow_handler"> |
288 | <title>Default Edge IRQ flow handler</title> | 309 | <title>Default Edge IRQ flow handler</title> |
289 | <para> | 310 | <para> |
@@ -294,20 +315,19 @@ desc->chip->end(); | |||
294 | The following control flow is implemented (simplified excerpt): | 315 | The following control flow is implemented (simplified excerpt): |
295 | <programlisting> | 316 | <programlisting> |
296 | if (desc->status & running) { | 317 | if (desc->status & running) { |
297 | desc->chip->hold(); | 318 | desc->chip->irq_mask(); |
298 | desc->status |= pending | masked; | 319 | desc->status |= pending | masked; |
299 | return; | 320 | return; |
300 | } | 321 | } |
301 | desc->chip->start(); | 322 | desc->chip->irq_ack(); |
302 | desc->status |= running; | 323 | desc->status |= running; |
303 | do { | 324 | do { |
304 | if (desc->status & masked) | 325 | if (desc->status & masked) |
305 | desc->chip->enable(); | 326 | desc->chip->irq_unmask(); |
306 | desc->status &= ~pending; | 327 | desc->status &= ~pending; |
307 | handle_IRQ_event(desc->action); | 328 | handle_IRQ_event(desc->action); |
308 | } while (status & pending); | 329 | } while (status & pending); |
309 | desc->status &= ~running; | 330 | desc->status &= ~running; |
310 | desc->chip->end(); | ||
311 | </programlisting> | 331 | </programlisting> |
312 | </para> | 332 | </para> |
313 | </sect3> | 333 | </sect3> |
@@ -342,9 +362,9 @@ handle_IRQ_event(desc->action); | |||
342 | <para> | 362 | <para> |
343 | The following control flow is implemented (simplified excerpt): | 363 | The following control flow is implemented (simplified excerpt): |
344 | <programlisting> | 364 | <programlisting> |
345 | desc->chip->start(); | ||
346 | handle_IRQ_event(desc->action); | 365 | handle_IRQ_event(desc->action); |
347 | desc->chip->end(); | 366 | if (desc->chip->irq_eoi) |
367 | desc->chip->irq_eoi(); | ||
348 | </programlisting> | 368 | </programlisting> |
349 | </para> | 369 | </para> |
350 | </sect3> | 370 | </sect3> |
@@ -375,8 +395,7 @@ desc->chip->end(); | |||
375 | mechanism. (It's necessary to enable CONFIG_HARDIRQS_SW_RESEND when | 395 | mechanism. (It's necessary to enable CONFIG_HARDIRQS_SW_RESEND when |
376 | you want to use the delayed interrupt disable feature and your | 396 | you want to use the delayed interrupt disable feature and your |
377 | hardware is not capable of retriggering an interrupt.) | 397 | hardware is not capable of retriggering an interrupt.) |
378 | The delayed interrupt disable can be runtime enabled, per interrupt, | 398 | The delayed interrupt disable is not configurable. |
379 | by setting the IRQ_DELAYED_DISABLE flag in the irq_desc status field. | ||
380 | </para> | 399 | </para> |
381 | </sect2> | 400 | </sect2> |
382 | </sect1> | 401 | </sect1> |
@@ -387,13 +406,13 @@ desc->chip->end(); | |||
387 | contains all the direct chip relevant functions, which | 406 | contains all the direct chip relevant functions, which |
388 | can be utilized by the irq flow implementations. | 407 | can be utilized by the irq flow implementations. |
389 | <itemizedlist> | 408 | <itemizedlist> |
390 | <listitem><para>ack()</para></listitem> | 409 | <listitem><para>irq_ack()</para></listitem> |
391 | <listitem><para>mask_ack() - Optional, recommended for performance</para></listitem> | 410 | <listitem><para>irq_mask_ack() - Optional, recommended for performance</para></listitem> |
392 | <listitem><para>mask()</para></listitem> | 411 | <listitem><para>irq_mask()</para></listitem> |
393 | <listitem><para>unmask()</para></listitem> | 412 | <listitem><para>irq_unmask()</para></listitem> |
394 | <listitem><para>retrigger() - Optional</para></listitem> | 413 | <listitem><para>irq_retrigger() - Optional</para></listitem> |
395 | <listitem><para>set_type() - Optional</para></listitem> | 414 | <listitem><para>irq_set_type() - Optional</para></listitem> |
396 | <listitem><para>set_wake() - Optional</para></listitem> | 415 | <listitem><para>irq_set_wake() - Optional</para></listitem> |
397 | </itemizedlist> | 416 | </itemizedlist> |
398 | These primitives are strictly intended to mean what they say: ack means | 417 | These primitives are strictly intended to mean what they say: ack means |
399 | ACK, masking means masking of an IRQ line, etc. It is up to the flow | 418 | ACK, masking means masking of an IRQ line, etc. It is up to the flow |
@@ -458,6 +477,7 @@ desc->chip->end(); | |||
458 | <para> | 477 | <para> |
459 | This chapter contains the autogenerated documentation of the internal functions. | 478 | This chapter contains the autogenerated documentation of the internal functions. |
460 | </para> | 479 | </para> |
480 | !Ikernel/irq/irqdesc.c | ||
461 | !Ikernel/irq/handle.c | 481 | !Ikernel/irq/handle.c |
462 | !Ikernel/irq/chip.c | 482 | !Ikernel/irq/chip.c |
463 | </chapter> | 483 | </chapter> |
diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl index a20c6f6fffc..6b4e07f28b6 100644 --- a/Documentation/DocBook/kernel-api.tmpl +++ b/Documentation/DocBook/kernel-api.tmpl | |||
@@ -57,7 +57,6 @@ | |||
57 | </para> | 57 | </para> |
58 | 58 | ||
59 | <sect1><title>String Conversions</title> | 59 | <sect1><title>String Conversions</title> |
60 | !Ilib/vsprintf.c | ||
61 | !Elib/vsprintf.c | 60 | !Elib/vsprintf.c |
62 | </sect1> | 61 | </sect1> |
63 | <sect1><title>String Manipulation</title> | 62 | <sect1><title>String Manipulation</title> |
@@ -258,7 +257,8 @@ X!Earch/x86/kernel/mca_32.c | |||
258 | !Iblock/blk-sysfs.c | 257 | !Iblock/blk-sysfs.c |
259 | !Eblock/blk-settings.c | 258 | !Eblock/blk-settings.c |
260 | !Eblock/blk-exec.c | 259 | !Eblock/blk-exec.c |
261 | !Eblock/blk-barrier.c | 260 | !Eblock/blk-flush.c |
261 | !Eblock/blk-lib.c | ||
262 | !Eblock/blk-tag.c | 262 | !Eblock/blk-tag.c |
263 | !Iblock/blk-tag.c | 263 | !Iblock/blk-tag.c |
264 | !Eblock/blk-integrity.c | 264 | !Eblock/blk-integrity.c |
diff --git a/Documentation/DocBook/kernel-locking.tmpl b/Documentation/DocBook/kernel-locking.tmpl index 0b1a3f97f28..f66f4df1869 100644 --- a/Documentation/DocBook/kernel-locking.tmpl +++ b/Documentation/DocBook/kernel-locking.tmpl | |||
@@ -1645,7 +1645,9 @@ the amount of locking which needs to be done. | |||
1645 | all the readers who were traversing the list when we deleted the | 1645 | all the readers who were traversing the list when we deleted the |
1646 | element are finished. We use <function>call_rcu()</function> to | 1646 | element are finished. We use <function>call_rcu()</function> to |
1647 | register a callback which will actually destroy the object once | 1647 | register a callback which will actually destroy the object once |
1648 | the readers are finished. | 1648 | all pre-existing readers are finished. Alternatively, |
1649 | <function>synchronize_rcu()</function> may be used to block until | ||
1650 | all pre-existing are finished. | ||
1649 | </para> | 1651 | </para> |
1650 | <para> | 1652 | <para> |
1651 | But how does Read Copy Update know when the readers are | 1653 | But how does Read Copy Update know when the readers are |
@@ -1714,7 +1716,7 @@ the amount of locking which needs to be done. | |||
1714 | - object_put(obj); | 1716 | - object_put(obj); |
1715 | + list_del_rcu(&obj->list); | 1717 | + list_del_rcu(&obj->list); |
1716 | cache_num--; | 1718 | cache_num--; |
1717 | + call_rcu(&obj->rcu, cache_delete_rcu, obj); | 1719 | + call_rcu(&obj->rcu, cache_delete_rcu); |
1718 | } | 1720 | } |
1719 | 1721 | ||
1720 | /* Must be holding cache_lock */ | 1722 | /* Must be holding cache_lock */ |
@@ -1725,14 +1727,6 @@ the amount of locking which needs to be done. | |||
1725 | if (++cache_num > MAX_CACHE_SIZE) { | 1727 | if (++cache_num > MAX_CACHE_SIZE) { |
1726 | struct object *i, *outcast = NULL; | 1728 | struct object *i, *outcast = NULL; |
1727 | list_for_each_entry(i, &cache, list) { | 1729 | list_for_each_entry(i, &cache, list) { |
1728 | @@ -85,6 +94,7 @@ | ||
1729 | obj->popularity = 0; | ||
1730 | atomic_set(&obj->refcnt, 1); /* The cache holds a reference */ | ||
1731 | spin_lock_init(&obj->lock); | ||
1732 | + INIT_RCU_HEAD(&obj->rcu); | ||
1733 | |||
1734 | spin_lock_irqsave(&cache_lock, flags); | ||
1735 | __cache_add(obj); | ||
1736 | @@ -104,12 +114,11 @@ | 1730 | @@ -104,12 +114,11 @@ |
1737 | struct object *cache_find(int id) | 1731 | struct object *cache_find(int id) |
1738 | { | 1732 | { |
@@ -1961,6 +1955,12 @@ machines due to caching. | |||
1961 | </sect1> | 1955 | </sect1> |
1962 | </chapter> | 1956 | </chapter> |
1963 | 1957 | ||
1958 | <chapter id="apiref"> | ||
1959 | <title>Mutex API reference</title> | ||
1960 | !Iinclude/linux/mutex.h | ||
1961 | !Ekernel/mutex.c | ||
1962 | </chapter> | ||
1963 | |||
1964 | <chapter id="references"> | 1964 | <chapter id="references"> |
1965 | <title>Further reading</title> | 1965 | <title>Further reading</title> |
1966 | 1966 | ||
diff --git a/Documentation/DocBook/tracepoint.tmpl b/Documentation/DocBook/tracepoint.tmpl index e8473eae2a2..b57a9ede322 100644 --- a/Documentation/DocBook/tracepoint.tmpl +++ b/Documentation/DocBook/tracepoint.tmpl | |||
@@ -104,4 +104,9 @@ | |||
104 | <title>Block IO</title> | 104 | <title>Block IO</title> |
105 | !Iinclude/trace/events/block.h | 105 | !Iinclude/trace/events/block.h |
106 | </chapter> | 106 | </chapter> |
107 | |||
108 | <chapter id="workqueue"> | ||
109 | <title>Workqueue</title> | ||
110 | !Iinclude/trace/events/workqueue.h | ||
111 | </chapter> | ||
107 | </book> | 112 | </book> |
diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt index 790d1a81237..0c134f8afc6 100644 --- a/Documentation/RCU/checklist.txt +++ b/Documentation/RCU/checklist.txt | |||
@@ -218,13 +218,22 @@ over a rather long period of time, but improvements are always welcome! | |||
218 | include: | 218 | include: |
219 | 219 | ||
220 | a. Keeping a count of the number of data-structure elements | 220 | a. Keeping a count of the number of data-structure elements |
221 | used by the RCU-protected data structure, including those | 221 | used by the RCU-protected data structure, including |
222 | waiting for a grace period to elapse. Enforce a limit | 222 | those waiting for a grace period to elapse. Enforce a |
223 | on this number, stalling updates as needed to allow | 223 | limit on this number, stalling updates as needed to allow |
224 | previously deferred frees to complete. | 224 | previously deferred frees to complete. Alternatively, |
225 | 225 | limit only the number awaiting deferred free rather than | |
226 | Alternatively, limit only the number awaiting deferred | 226 | the total number of elements. |
227 | free rather than the total number of elements. | 227 | |
228 | One way to stall the updates is to acquire the update-side | ||
229 | mutex. (Don't try this with a spinlock -- other CPUs | ||
230 | spinning on the lock could prevent the grace period | ||
231 | from ever ending.) Another way to stall the updates | ||
232 | is for the updates to use a wrapper function around | ||
233 | the memory allocator, so that this wrapper function | ||
234 | simulates OOM when there is too much memory awaiting an | ||
235 | RCU grace period. There are of course many other | ||
236 | variations on this theme. | ||
228 | 237 | ||
229 | b. Limiting update rate. For example, if updates occur only | 238 | b. Limiting update rate. For example, if updates occur only |
230 | once per hour, then no explicit rate limiting is required, | 239 | once per hour, then no explicit rate limiting is required, |
@@ -365,3 +374,26 @@ over a rather long period of time, but improvements are always welcome! | |||
365 | and the compiler to freely reorder code into and out of RCU | 374 | and the compiler to freely reorder code into and out of RCU |
366 | read-side critical sections. It is the responsibility of the | 375 | read-side critical sections. It is the responsibility of the |
367 | RCU update-side primitives to deal with this. | 376 | RCU update-side primitives to deal with this. |
377 | |||
378 | 17. Use CONFIG_PROVE_RCU, CONFIG_DEBUG_OBJECTS_RCU_HEAD, and | ||
379 | the __rcu sparse checks to validate your RCU code. These | ||
380 | can help find problems as follows: | ||
381 | |||
382 | CONFIG_PROVE_RCU: check that accesses to RCU-protected data | ||
383 | structures are carried out under the proper RCU | ||
384 | read-side critical section, while holding the right | ||
385 | combination of locks, or whatever other conditions | ||
386 | are appropriate. | ||
387 | |||
388 | CONFIG_DEBUG_OBJECTS_RCU_HEAD: check that you don't pass the | ||
389 | same object to call_rcu() (or friends) before an RCU | ||
390 | grace period has elapsed since the last time that you | ||
391 | passed that same object to call_rcu() (or friends). | ||
392 | |||
393 | __rcu sparse checks: tag the pointer to the RCU-protected data | ||
394 | structure with __rcu, and sparse will warn you if you | ||
395 | access that pointer without the services of one of the | ||
396 | variants of rcu_dereference(). | ||
397 | |||
398 | These debugging aids can help you find problems that are | ||
399 | otherwise extremely difficult to spot. | ||
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index 44c6dcc93d6..862c08ef1fd 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt | |||
@@ -80,6 +80,24 @@ o A CPU looping with bottom halves disabled. This condition can | |||
80 | o For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the kernel | 80 | o For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the kernel |
81 | without invoking schedule(). | 81 | without invoking schedule(). |
82 | 82 | ||
83 | o A CPU-bound real-time task in a CONFIG_PREEMPT kernel, which might | ||
84 | happen to preempt a low-priority task in the middle of an RCU | ||
85 | read-side critical section. This is especially damaging if | ||
86 | that low-priority task is not permitted to run on any other CPU, | ||
87 | in which case the next RCU grace period can never complete, which | ||
88 | will eventually cause the system to run out of memory and hang. | ||
89 | While the system is in the process of running itself out of | ||
90 | memory, you might see stall-warning messages. | ||
91 | |||
92 | o A CPU-bound real-time task in a CONFIG_PREEMPT_RT kernel that | ||
93 | is running at a higher priority than the RCU softirq threads. | ||
94 | This will prevent RCU callbacks from ever being invoked, | ||
95 | and in a CONFIG_TREE_PREEMPT_RCU kernel will further prevent | ||
96 | RCU grace periods from ever completing. Either way, the | ||
97 | system will eventually run out of memory and hang. In the | ||
98 | CONFIG_TREE_PREEMPT_RCU case, you might see stall-warning | ||
99 | messages. | ||
100 | |||
83 | o A bug in the RCU implementation. | 101 | o A bug in the RCU implementation. |
84 | 102 | ||
85 | o A hardware failure. This is quite unlikely, but has occurred | 103 | o A hardware failure. This is quite unlikely, but has occurred |
diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt index efd8cc95c06..a851118775d 100644 --- a/Documentation/RCU/trace.txt +++ b/Documentation/RCU/trace.txt | |||
@@ -125,6 +125,17 @@ o "b" is the batch limit for this CPU. If more than this number | |||
125 | of RCU callbacks is ready to invoke, then the remainder will | 125 | of RCU callbacks is ready to invoke, then the remainder will |
126 | be deferred. | 126 | be deferred. |
127 | 127 | ||
128 | o "ci" is the number of RCU callbacks that have been invoked for | ||
129 | this CPU. Note that ci+ql is the number of callbacks that have | ||
130 | been registered in absence of CPU-hotplug activity. | ||
131 | |||
132 | o "co" is the number of RCU callbacks that have been orphaned due to | ||
133 | this CPU going offline. | ||
134 | |||
135 | o "ca" is the number of RCU callbacks that have been adopted due to | ||
136 | other CPUs going offline. Note that ci+co-ca+ql is the number of | ||
137 | RCU callbacks registered on this CPU. | ||
138 | |||
128 | There is also an rcu/rcudata.csv file with the same information in | 139 | There is also an rcu/rcudata.csv file with the same information in |
129 | comma-separated-variable spreadsheet format. | 140 | comma-separated-variable spreadsheet format. |
130 | 141 | ||
@@ -180,7 +191,7 @@ o "s" is the "signaled" state that drives force_quiescent_state()'s | |||
180 | 191 | ||
181 | o "jfq" is the number of jiffies remaining for this grace period | 192 | o "jfq" is the number of jiffies remaining for this grace period |
182 | before force_quiescent_state() is invoked to help push things | 193 | before force_quiescent_state() is invoked to help push things |
183 | along. Note that CPUs in dyntick-idle mode thoughout the grace | 194 | along. Note that CPUs in dyntick-idle mode throughout the grace |
184 | period will not report on their own, but rather must be check by | 195 | period will not report on their own, but rather must be check by |
185 | some other CPU via force_quiescent_state(). | 196 | some other CPU via force_quiescent_state(). |
186 | 197 | ||
diff --git a/Documentation/arm/00-INDEX b/Documentation/arm/00-INDEX index 7f5fc3ba9c9..ecf7d04bca2 100644 --- a/Documentation/arm/00-INDEX +++ b/Documentation/arm/00-INDEX | |||
@@ -6,6 +6,8 @@ Interrupts | |||
6 | - ARM Interrupt subsystem documentation | 6 | - ARM Interrupt subsystem documentation |
7 | IXP2000 | 7 | IXP2000 |
8 | - Release Notes for Linux on Intel's IXP2000 Network Processor | 8 | - Release Notes for Linux on Intel's IXP2000 Network Processor |
9 | msm | ||
10 | - MSM specific documentation | ||
9 | Netwinder | 11 | Netwinder |
10 | - Netwinder specific documentation | 12 | - Netwinder specific documentation |
11 | Porting | 13 | Porting |
diff --git a/Documentation/arm/msm/gpiomux.txt b/Documentation/arm/msm/gpiomux.txt new file mode 100644 index 00000000000..67a81620adf --- /dev/null +++ b/Documentation/arm/msm/gpiomux.txt | |||
@@ -0,0 +1,176 @@ | |||
1 | This document provides an overview of the msm_gpiomux interface, which | ||
2 | is used to provide gpio pin multiplexing and configuration on mach-msm | ||
3 | targets. | ||
4 | |||
5 | History | ||
6 | ======= | ||
7 | |||
8 | The first-generation API for gpio configuration & multiplexing on msm | ||
9 | is the function gpio_tlmm_config(). This function has a few notable | ||
10 | shortcomings, which led to its deprecation and replacement by gpiomux: | ||
11 | |||
12 | The 'disable' parameter: Setting the second parameter to | ||
13 | gpio_tlmm_config to GPIO_CFG_DISABLE tells the peripheral | ||
14 | processor in charge of the subsystem to perform a look-up into a | ||
15 | low-power table and apply the low-power/sleep setting for the pin. | ||
16 | As the msm family evolved this became problematic. Not all pins | ||
17 | have sleep settings, not all peripheral processors will accept requests | ||
18 | to apply said sleep settings, and not all msm targets have their gpio | ||
19 | subsystems managed by a peripheral processor. In order to get consistent | ||
20 | behavior on all targets, drivers are forced to ignore this parameter, | ||
21 | rendering it useless. | ||
22 | |||
23 | The 'direction' flag: for all mux-settings other than raw-gpio (0), | ||
24 | the output-enable bit of a gpio is hard-wired to a known | ||
25 | input (usually VDD or ground). For those settings, the direction flag | ||
26 | is meaningless at best, and deceptive at worst. In addition, using the | ||
27 | direction flag to change output-enable (OE) directly can cause trouble in | ||
28 | gpiolib, which has no visibility into gpio direction changes made | ||
29 | in this way. Direction control in gpio mode should be made through gpiolib. | ||
30 | |||
31 | Key Features of gpiomux | ||
32 | ======================= | ||
33 | |||
34 | - A consistent interface across all generations of msm. Drivers can expect | ||
35 | the same results on every target. | ||
36 | - gpiomux plays nicely with gpiolib. Functions that should belong to gpiolib | ||
37 | are left to gpiolib and not duplicated here. gpiomux is written with the | ||
38 | intent that gpio_chips will call gpiomux reference-counting methods | ||
39 | from their request() and free() hooks, providing full integration. | ||
40 | - Tabular configuration. Instead of having to call gpio_tlmm_config | ||
41 | hundreds of times, gpio configuration is placed in a single table. | ||
42 | - Per-gpio sleep. Each gpio is individually reference counted, allowing only | ||
43 | those lines which are in use to be put in high-power states. | ||
44 | - 0 means 'do nothing': all flags are designed so that the default memset-zero | ||
45 | equates to a sensible default of 'no configuration', preventing users | ||
46 | from having to provide hundreds of 'no-op' configs for unused or | ||
47 | unwanted lines. | ||
48 | |||
49 | Usage | ||
50 | ===== | ||
51 | |||
52 | To use gpiomux, provide configuration information for relevant gpio lines | ||
53 | in the msm_gpiomux_configs table. Since a 0 equates to "unconfigured", | ||
54 | only those lines to be managed by gpiomux need to be specified. Here | ||
55 | is a completely fictional example: | ||
56 | |||
57 | struct msm_gpiomux_config msm_gpiomux_configs[GPIOMUX_NGPIOS] = { | ||
58 | [12] = { | ||
59 | .active = GPIOMUX_VALID | GPIOMUX_DRV_8MA | GPIOMUX_FUNC_1, | ||
60 | .suspended = GPIOMUX_VALID | GPIOMUX_PULL_DOWN, | ||
61 | }, | ||
62 | [34] = { | ||
63 | .suspended = GPIOMUX_VALID | GPIOMUX_PULL_DOWN, | ||
64 | }, | ||
65 | }; | ||
66 | |||
67 | To indicate that a gpio is in use, call msm_gpiomux_get() to increase | ||
68 | its reference count. To decrease the reference count, call msm_gpiomux_put(). | ||
69 | |||
70 | The effect of this configuration is as follows: | ||
71 | |||
72 | When the system boots, gpios 12 and 34 will be initialized with their | ||
73 | 'suspended' configurations. All other gpios, which were left unconfigured, | ||
74 | will not be touched. | ||
75 | |||
76 | When msm_gpiomux_get() is called on gpio 12 to raise its reference count | ||
77 | above 0, its active configuration will be applied. Since no other gpio | ||
78 | line has a valid active configuration, msm_gpiomux_get() will have no | ||
79 | effect on any other line. | ||
80 | |||
81 | When msm_gpiomux_put() is called on gpio 12 or 34 to drop their reference | ||
82 | count to 0, their suspended configurations will be applied. | ||
83 | Since no other gpio line has a valid suspended configuration, no other | ||
84 | gpio line will be effected by msm_gpiomux_put(). Since gpio 34 has no valid | ||
85 | active configuration, this is effectively a no-op for gpio 34 as well, | ||
86 | with one small caveat, see the section "About Output-Enable Settings". | ||
87 | |||
88 | All of the GPIOMUX_VALID flags may seem like unnecessary overhead, but | ||
89 | they address some important issues. As unused entries (all those | ||
90 | except 12 and 34) are zero-filled, gpiomux needs a way to distinguish | ||
91 | the used fields from the unused. In addition, the all-zero pattern | ||
92 | is a valid configuration! Therefore, gpiomux defines an additional bit | ||
93 | which is used to indicate when a field is used. This has the pleasant | ||
94 | side-effect of allowing calls to msm_gpiomux_write to use '0' to indicate | ||
95 | that a value should not be changed: | ||
96 | |||
97 | msm_gpiomux_write(0, GPIOMUX_VALID, 0); | ||
98 | |||
99 | replaces the active configuration of gpio 0 with an all-zero configuration, | ||
100 | but leaves the suspended configuration as it was. | ||
101 | |||
102 | Static Configurations | ||
103 | ===================== | ||
104 | |||
105 | To install a static configuration, which is applied at boot and does | ||
106 | not change after that, install a configuration with a suspended component | ||
107 | but no active component, as in the previous example: | ||
108 | |||
109 | [34] = { | ||
110 | .suspended = GPIOMUX_VALID | GPIOMUX_PULL_DOWN, | ||
111 | }, | ||
112 | |||
113 | The suspended setting is applied during boot, and the lack of any valid | ||
114 | active setting prevents any other setting from being applied at runtime. | ||
115 | If other subsystems attempting to access the line is a concern, one could | ||
116 | *really* anchor the configuration down by calling msm_gpiomux_get on the | ||
117 | line at initialization to move the line into active mode. With the line | ||
118 | held, it will never be re-suspended, and with no valid active configuration, | ||
119 | no new configurations will be applied. | ||
120 | |||
121 | But then, if having other subsystems grabbing for the line is truly a concern, | ||
122 | it should be reserved with gpio_request instead, which carries an implicit | ||
123 | msm_gpiomux_get. | ||
124 | |||
125 | gpiomux and gpiolib | ||
126 | =================== | ||
127 | |||
128 | It is expected that msm gpio_chips will call msm_gpiomux_get() and | ||
129 | msm_gpiomux_put() from their request and free hooks, like this fictional | ||
130 | example: | ||
131 | |||
132 | static int request(struct gpio_chip *chip, unsigned offset) | ||
133 | { | ||
134 | return msm_gpiomux_get(chip->base + offset); | ||
135 | } | ||
136 | |||
137 | static void free(struct gpio_chip *chip, unsigned offset) | ||
138 | { | ||
139 | msm_gpiomux_put(chip->base + offset); | ||
140 | } | ||
141 | |||
142 | ...somewhere in a gpio_chip declaration... | ||
143 | .request = request, | ||
144 | .free = free, | ||
145 | |||
146 | This provides important functionality: | ||
147 | - It guarantees that a gpio line will have its 'active' config applied | ||
148 | when the line is requested, and will not be suspended while the line | ||
149 | remains requested; and | ||
150 | - It guarantees that gpio-direction settings from gpiolib behave sensibly. | ||
151 | See "About Output-Enable Settings." | ||
152 | |||
153 | This mechanism allows for "auto-request" of gpiomux lines via gpiolib | ||
154 | when it is suitable. Drivers wishing more exact control are, of course, | ||
155 | free to also use msm_gpiomux_set and msm_gpiomux_get. | ||
156 | |||
157 | About Output-Enable Settings | ||
158 | ============================ | ||
159 | |||
160 | Some msm targets do not have the ability to query the current gpio | ||
161 | configuration setting. This means that changes made to the output-enable | ||
162 | (OE) bit by gpiolib cannot be consistently detected and preserved by gpiomux. | ||
163 | Therefore, when gpiomux applies a configuration setting, any direction | ||
164 | settings which may have been applied by gpiolib are lost and the default | ||
165 | input settings are re-applied. | ||
166 | |||
167 | For this reason, drivers should not assume that gpio direction settings | ||
168 | continue to hold if they free and then re-request a gpio. This seems like | ||
169 | common sense - after all, anybody could have obtained the line in the | ||
170 | meantime - but it needs saying. | ||
171 | |||
172 | This also means that calls to msm_gpiomux_write will reset the OE bit, | ||
173 | which means that if the gpio line is held by a client of gpiolib and | ||
174 | msm_gpiomux_write is called, the direction setting has been lost and | ||
175 | gpiolib's internal state has been broken. | ||
176 | Release gpio lines before reconfiguring them. | ||
diff --git a/Documentation/block/00-INDEX b/Documentation/block/00-INDEX index a406286f6f3..d111e3b23db 100644 --- a/Documentation/block/00-INDEX +++ b/Documentation/block/00-INDEX | |||
@@ -1,7 +1,5 @@ | |||
1 | 00-INDEX | 1 | 00-INDEX |
2 | - This file | 2 | - This file |
3 | barrier.txt | ||
4 | - I/O Barriers | ||
5 | biodoc.txt | 3 | biodoc.txt |
6 | - Notes on the Generic Block Layer Rewrite in Linux 2.5 | 4 | - Notes on the Generic Block Layer Rewrite in Linux 2.5 |
7 | capability.txt | 5 | capability.txt |
@@ -16,3 +14,5 @@ stat.txt | |||
16 | - Block layer statistics in /sys/block/<dev>/stat | 14 | - Block layer statistics in /sys/block/<dev>/stat |
17 | switching-sched.txt | 15 | switching-sched.txt |
18 | - Switching I/O schedulers at runtime | 16 | - Switching I/O schedulers at runtime |
17 | writeback_cache_control.txt | ||
18 | - Control of volatile write back caches | ||
diff --git a/Documentation/block/barrier.txt b/Documentation/block/barrier.txt deleted file mode 100644 index 2c2f24f634e..00000000000 --- a/Documentation/block/barrier.txt +++ /dev/null | |||
@@ -1,261 +0,0 @@ | |||
1 | I/O Barriers | ||
2 | ============ | ||
3 | Tejun Heo <htejun@gmail.com>, July 22 2005 | ||
4 | |||
5 | I/O barrier requests are used to guarantee ordering around the barrier | ||
6 | requests. Unless you're crazy enough to use disk drives for | ||
7 | implementing synchronization constructs (wow, sounds interesting...), | ||
8 | the ordering is meaningful only for write requests for things like | ||
9 | journal checkpoints. All requests queued before a barrier request | ||
10 | must be finished (made it to the physical medium) before the barrier | ||
11 | request is started, and all requests queued after the barrier request | ||
12 | must be started only after the barrier request is finished (again, | ||
13 | made it to the physical medium). | ||
14 | |||
15 | In other words, I/O barrier requests have the following two properties. | ||
16 | |||
17 | 1. Request ordering | ||
18 | |||
19 | Requests cannot pass the barrier request. Preceding requests are | ||
20 | processed before the barrier and following requests after. | ||
21 | |||
22 | Depending on what features a drive supports, this can be done in one | ||
23 | of the following three ways. | ||
24 | |||
25 | i. For devices which have queue depth greater than 1 (TCQ devices) and | ||
26 | support ordered tags, block layer can just issue the barrier as an | ||
27 | ordered request and the lower level driver, controller and drive | ||
28 | itself are responsible for making sure that the ordering constraint is | ||
29 | met. Most modern SCSI controllers/drives should support this. | ||
30 | |||
31 | NOTE: SCSI ordered tag isn't currently used due to limitation in the | ||
32 | SCSI midlayer, see the following random notes section. | ||
33 | |||
34 | ii. For devices which have queue depth greater than 1 but don't | ||
35 | support ordered tags, block layer ensures that the requests preceding | ||
36 | a barrier request finishes before issuing the barrier request. Also, | ||
37 | it defers requests following the barrier until the barrier request is | ||
38 | finished. Older SCSI controllers/drives and SATA drives fall in this | ||
39 | category. | ||
40 | |||
41 | iii. Devices which have queue depth of 1. This is a degenerate case | ||
42 | of ii. Just keeping issue order suffices. Ancient SCSI | ||
43 | controllers/drives and IDE drives are in this category. | ||
44 | |||
45 | 2. Forced flushing to physical medium | ||
46 | |||
47 | Again, if you're not gonna do synchronization with disk drives (dang, | ||
48 | it sounds even more appealing now!), the reason you use I/O barriers | ||
49 | is mainly to protect filesystem integrity when power failure or some | ||
50 | other events abruptly stop the drive from operating and possibly make | ||
51 | the drive lose data in its cache. So, I/O barriers need to guarantee | ||
52 | that requests actually get written to non-volatile medium in order. | ||
53 | |||
54 | There are four cases, | ||
55 | |||
56 | i. No write-back cache. Keeping requests ordered is enough. | ||
57 | |||
58 | ii. Write-back cache but no flush operation. There's no way to | ||
59 | guarantee physical-medium commit order. This kind of devices can't to | ||
60 | I/O barriers. | ||
61 | |||
62 | iii. Write-back cache and flush operation but no FUA (forced unit | ||
63 | access). We need two cache flushes - before and after the barrier | ||
64 | request. | ||
65 | |||
66 | iv. Write-back cache, flush operation and FUA. We still need one | ||
67 | flush to make sure requests preceding a barrier are written to medium, | ||
68 | but post-barrier flush can be avoided by using FUA write on the | ||
69 | barrier itself. | ||
70 | |||
71 | |||
72 | How to support barrier requests in drivers | ||
73 | ------------------------------------------ | ||
74 | |||
75 | All barrier handling is done inside block layer proper. All low level | ||
76 | drivers have to are implementing its prepare_flush_fn and using one | ||
77 | the following two functions to indicate what barrier type it supports | ||
78 | and how to prepare flush requests. Note that the term 'ordered' is | ||
79 | used to indicate the whole sequence of performing barrier requests | ||
80 | including draining and flushing. | ||
81 | |||
82 | typedef void (prepare_flush_fn)(struct request_queue *q, struct request *rq); | ||
83 | |||
84 | int blk_queue_ordered(struct request_queue *q, unsigned ordered, | ||
85 | prepare_flush_fn *prepare_flush_fn); | ||
86 | |||
87 | @q : the queue in question | ||
88 | @ordered : the ordered mode the driver/device supports | ||
89 | @prepare_flush_fn : this function should prepare @rq such that it | ||
90 | flushes cache to physical medium when executed | ||
91 | |||
92 | For example, SCSI disk driver's prepare_flush_fn looks like the | ||
93 | following. | ||
94 | |||
95 | static void sd_prepare_flush(struct request_queue *q, struct request *rq) | ||
96 | { | ||
97 | memset(rq->cmd, 0, sizeof(rq->cmd)); | ||
98 | rq->cmd_type = REQ_TYPE_BLOCK_PC; | ||
99 | rq->timeout = SD_TIMEOUT; | ||
100 | rq->cmd[0] = SYNCHRONIZE_CACHE; | ||
101 | rq->cmd_len = 10; | ||
102 | } | ||
103 | |||
104 | The following seven ordered modes are supported. The following table | ||
105 | shows which mode should be used depending on what features a | ||
106 | device/driver supports. In the leftmost column of table, | ||
107 | QUEUE_ORDERED_ prefix is omitted from the mode names to save space. | ||
108 | |||
109 | The table is followed by description of each mode. Note that in the | ||
110 | descriptions of QUEUE_ORDERED_DRAIN*, '=>' is used whereas '->' is | ||
111 | used for QUEUE_ORDERED_TAG* descriptions. '=>' indicates that the | ||
112 | preceding step must be complete before proceeding to the next step. | ||
113 | '->' indicates that the next step can start as soon as the previous | ||
114 | step is issued. | ||
115 | |||
116 | write-back cache ordered tag flush FUA | ||
117 | ----------------------------------------------------------------------- | ||
118 | NONE yes/no N/A no N/A | ||
119 | DRAIN no no N/A N/A | ||
120 | DRAIN_FLUSH yes no yes no | ||
121 | DRAIN_FUA yes no yes yes | ||
122 | TAG no yes N/A N/A | ||
123 | TAG_FLUSH yes yes yes no | ||
124 | TAG_FUA yes yes yes yes | ||
125 | |||
126 | |||
127 | QUEUE_ORDERED_NONE | ||
128 | I/O barriers are not needed and/or supported. | ||
129 | |||
130 | Sequence: N/A | ||
131 | |||
132 | QUEUE_ORDERED_DRAIN | ||
133 | Requests are ordered by draining the request queue and cache | ||
134 | flushing isn't needed. | ||
135 | |||
136 | Sequence: drain => barrier | ||
137 | |||
138 | QUEUE_ORDERED_DRAIN_FLUSH | ||
139 | Requests are ordered by draining the request queue and both | ||
140 | pre-barrier and post-barrier cache flushings are needed. | ||
141 | |||
142 | Sequence: drain => preflush => barrier => postflush | ||
143 | |||
144 | QUEUE_ORDERED_DRAIN_FUA | ||
145 | Requests are ordered by draining the request queue and | ||
146 | pre-barrier cache flushing is needed. By using FUA on barrier | ||
147 | request, post-barrier flushing can be skipped. | ||
148 | |||
149 | Sequence: drain => preflush => barrier | ||
150 | |||
151 | QUEUE_ORDERED_TAG | ||
152 | Requests are ordered by ordered tag and cache flushing isn't | ||
153 | needed. | ||
154 | |||
155 | Sequence: barrier | ||
156 | |||
157 | QUEUE_ORDERED_TAG_FLUSH | ||
158 | Requests are ordered by ordered tag and both pre-barrier and | ||
159 | post-barrier cache flushings are needed. | ||
160 | |||
161 | Sequence: preflush -> barrier -> postflush | ||
162 | |||
163 | QUEUE_ORDERED_TAG_FUA | ||
164 | Requests are ordered by ordered tag and pre-barrier cache | ||
165 | flushing is needed. By using FUA on barrier request, | ||
166 | post-barrier flushing can be skipped. | ||
167 | |||
168 | Sequence: preflush -> barrier | ||
169 | |||
170 | |||
171 | Random notes/caveats | ||
172 | -------------------- | ||
173 | |||
174 | * SCSI layer currently can't use TAG ordering even if the drive, | ||
175 | controller and driver support it. The problem is that SCSI midlayer | ||
176 | request dispatch function is not atomic. It releases queue lock and | ||
177 | switch to SCSI host lock during issue and it's possible and likely to | ||
178 | happen in time that requests change their relative positions. Once | ||
179 | this problem is solved, TAG ordering can be enabled. | ||
180 | |||
181 | * Currently, no matter which ordered mode is used, there can be only | ||
182 | one barrier request in progress. All I/O barriers are held off by | ||
183 | block layer until the previous I/O barrier is complete. This doesn't | ||
184 | make any difference for DRAIN ordered devices, but, for TAG ordered | ||
185 | devices with very high command latency, passing multiple I/O barriers | ||
186 | to low level *might* be helpful if they are very frequent. Well, this | ||
187 | certainly is a non-issue. I'm writing this just to make clear that no | ||
188 | two I/O barrier is ever passed to low-level driver. | ||
189 | |||
190 | * Completion order. Requests in ordered sequence are issued in order | ||
191 | but not required to finish in order. Barrier implementation can | ||
192 | handle out-of-order completion of ordered sequence. IOW, the requests | ||
193 | MUST be processed in order but the hardware/software completion paths | ||
194 | are allowed to reorder completion notifications - eg. current SCSI | ||
195 | midlayer doesn't preserve completion order during error handling. | ||
196 | |||
197 | * Requeueing order. Low-level drivers are free to requeue any request | ||
198 | after they removed it from the request queue with | ||
199 | blkdev_dequeue_request(). As barrier sequence should be kept in order | ||
200 | when requeued, generic elevator code takes care of putting requests in | ||
201 | order around barrier. See blk_ordered_req_seq() and | ||
202 | ELEVATOR_INSERT_REQUEUE handling in __elv_add_request() for details. | ||
203 | |||
204 | Note that block drivers must not requeue preceding requests while | ||
205 | completing latter requests in an ordered sequence. Currently, no | ||
206 | error checking is done against this. | ||
207 | |||
208 | * Error handling. Currently, block layer will report error to upper | ||
209 | layer if any of requests in an ordered sequence fails. Unfortunately, | ||
210 | this doesn't seem to be enough. Look at the following request flow. | ||
211 | QUEUE_ORDERED_TAG_FLUSH is in use. | ||
212 | |||
213 | [0] [1] [2] [3] [pre] [barrier] [post] < [4] [5] [6] ... > | ||
214 | still in elevator | ||
215 | |||
216 | Let's say request [2], [3] are write requests to update file system | ||
217 | metadata (journal or whatever) and [barrier] is used to mark that | ||
218 | those updates are valid. Consider the following sequence. | ||
219 | |||
220 | i. Requests [0] ~ [post] leaves the request queue and enters | ||
221 | low-level driver. | ||
222 | ii. After a while, unfortunately, something goes wrong and the | ||
223 | drive fails [2]. Note that any of [0], [1] and [3] could have | ||
224 | completed by this time, but [pre] couldn't have been finished | ||
225 | as the drive must process it in order and it failed before | ||
226 | processing that command. | ||
227 | iii. Error handling kicks in and determines that the error is | ||
228 | unrecoverable and fails [2], and resumes operation. | ||
229 | iv. [pre] [barrier] [post] gets processed. | ||
230 | v. *BOOM* power fails | ||
231 | |||
232 | The problem here is that the barrier request is *supposed* to indicate | ||
233 | that filesystem update requests [2] and [3] made it safely to the | ||
234 | physical medium and, if the machine crashes after the barrier is | ||
235 | written, filesystem recovery code can depend on that. Sadly, that | ||
236 | isn't true in this case anymore. IOW, the success of a I/O barrier | ||
237 | should also be dependent on success of some of the preceding requests, | ||
238 | where only upper layer (filesystem) knows what 'some' is. | ||
239 | |||
240 | This can be solved by implementing a way to tell the block layer which | ||
241 | requests affect the success of the following barrier request and | ||
242 | making lower lever drivers to resume operation on error only after | ||
243 | block layer tells it to do so. | ||
244 | |||
245 | As the probability of this happening is very low and the drive should | ||
246 | be faulty, implementing the fix is probably an overkill. But, still, | ||
247 | it's there. | ||
248 | |||
249 | * In previous drafts of barrier implementation, there was fallback | ||
250 | mechanism such that, if FUA or ordered TAG fails, less fancy ordered | ||
251 | mode can be selected and the failed barrier request is retried | ||
252 | automatically. The rationale for this feature was that as FUA is | ||
253 | pretty new in ATA world and ordered tag was never used widely, there | ||
254 | could be devices which report to support those features but choke when | ||
255 | actually given such requests. | ||
256 | |||
257 | This was removed for two reasons 1. it's an overkill 2. it's | ||
258 | impossible to implement properly when TAG ordering is used as low | ||
259 | level drivers resume after an error automatically. If it's ever | ||
260 | needed adding it back and modifying low level drivers accordingly | ||
261 | shouldn't be difficult. | ||
diff --git a/Documentation/block/cfq-iosched.txt b/Documentation/block/cfq-iosched.txt new file mode 100644 index 00000000000..e578feed6d8 --- /dev/null +++ b/Documentation/block/cfq-iosched.txt | |||
@@ -0,0 +1,45 @@ | |||
1 | CFQ ioscheduler tunables | ||
2 | ======================== | ||
3 | |||
4 | slice_idle | ||
5 | ---------- | ||
6 | This specifies how long CFQ should idle for next request on certain cfq queues | ||
7 | (for sequential workloads) and service trees (for random workloads) before | ||
8 | queue is expired and CFQ selects next queue to dispatch from. | ||
9 | |||
10 | By default slice_idle is a non-zero value. That means by default we idle on | ||
11 | queues/service trees. This can be very helpful on highly seeky media like | ||
12 | single spindle SATA/SAS disks where we can cut down on overall number of | ||
13 | seeks and see improved throughput. | ||
14 | |||
15 | Setting slice_idle to 0 will remove all the idling on queues/service tree | ||
16 | level and one should see an overall improved throughput on faster storage | ||
17 | devices like multiple SATA/SAS disks in hardware RAID configuration. The down | ||
18 | side is that isolation provided from WRITES also goes down and notion of | ||
19 | IO priority becomes weaker. | ||
20 | |||
21 | So depending on storage and workload, it might be useful to set slice_idle=0. | ||
22 | In general I think for SATA/SAS disks and software RAID of SATA/SAS disks | ||
23 | keeping slice_idle enabled should be useful. For any configurations where | ||
24 | there are multiple spindles behind single LUN (Host based hardware RAID | ||
25 | controller or for storage arrays), setting slice_idle=0 might end up in better | ||
26 | throughput and acceptable latencies. | ||
27 | |||
28 | CFQ IOPS Mode for group scheduling | ||
29 | =================================== | ||
30 | Basic CFQ design is to provide priority based time slices. Higher priority | ||
31 | process gets bigger time slice and lower priority process gets smaller time | ||
32 | slice. Measuring time becomes harder if storage is fast and supports NCQ and | ||
33 | it would be better to dispatch multiple requests from multiple cfq queues in | ||
34 | request queue at a time. In such scenario, it is not possible to measure time | ||
35 | consumed by single queue accurately. | ||
36 | |||
37 | What is possible though is to measure number of requests dispatched from a | ||
38 | single queue and also allow dispatch from multiple cfq queue at the same time. | ||
39 | This effectively becomes the fairness in terms of IOPS (IO operations per | ||
40 | second). | ||
41 | |||
42 | If one sets slice_idle=0 and if storage supports NCQ, CFQ internally switches | ||
43 | to IOPS mode and starts providing fairness in terms of number of requests | ||
44 | dispatched. Note that this mode switching takes effect only for group | ||
45 | scheduling. For non-cgroup users nothing should change. | ||
diff --git a/Documentation/block/writeback_cache_control.txt b/Documentation/block/writeback_cache_control.txt new file mode 100644 index 00000000000..83407d36630 --- /dev/null +++ b/Documentation/block/writeback_cache_control.txt | |||
@@ -0,0 +1,86 @@ | |||
1 | |||
2 | Explicit volatile write back cache control | ||
3 | ===================================== | ||
4 | |||
5 | Introduction | ||
6 | ------------ | ||
7 | |||
8 | Many storage devices, especially in the consumer market, come with volatile | ||
9 | write back caches. That means the devices signal I/O completion to the | ||
10 | operating system before data actually has hit the non-volatile storage. This | ||
11 | behavior obviously speeds up various workloads, but it means the operating | ||
12 | system needs to force data out to the non-volatile storage when it performs | ||
13 | a data integrity operation like fsync, sync or an unmount. | ||
14 | |||
15 | The Linux block layer provides two simple mechanisms that let filesystems | ||
16 | control the caching behavior of the storage device. These mechanisms are | ||
17 | a forced cache flush, and the Force Unit Access (FUA) flag for requests. | ||
18 | |||
19 | |||
20 | Explicit cache flushes | ||
21 | ---------------------- | ||
22 | |||
23 | The REQ_FLUSH flag can be OR ed into the r/w flags of a bio submitted from | ||
24 | the filesystem and will make sure the volatile cache of the storage device | ||
25 | has been flushed before the actual I/O operation is started. This explicitly | ||
26 | guarantees that previously completed write requests are on non-volatile | ||
27 | storage before the flagged bio starts. In addition the REQ_FLUSH flag can be | ||
28 | set on an otherwise empty bio structure, which causes only an explicit cache | ||
29 | flush without any dependent I/O. It is recommend to use | ||
30 | the blkdev_issue_flush() helper for a pure cache flush. | ||
31 | |||
32 | |||
33 | Forced Unit Access | ||
34 | ----------------- | ||
35 | |||
36 | The REQ_FUA flag can be OR ed into the r/w flags of a bio submitted from the | ||
37 | filesystem and will make sure that I/O completion for this request is only | ||
38 | signaled after the data has been committed to non-volatile storage. | ||
39 | |||
40 | |||
41 | Implementation details for filesystems | ||
42 | -------------------------------------- | ||
43 | |||
44 | Filesystems can simply set the REQ_FLUSH and REQ_FUA bits and do not have to | ||
45 | worry if the underlying devices need any explicit cache flushing and how | ||
46 | the Forced Unit Access is implemented. The REQ_FLUSH and REQ_FUA flags | ||
47 | may both be set on a single bio. | ||
48 | |||
49 | |||
50 | Implementation details for make_request_fn based block drivers | ||
51 | -------------------------------------------------------------- | ||
52 | |||
53 | These drivers will always see the REQ_FLUSH and REQ_FUA bits as they sit | ||
54 | directly below the submit_bio interface. For remapping drivers the REQ_FUA | ||
55 | bits need to be propagated to underlying devices, and a global flush needs | ||
56 | to be implemented for bios with the REQ_FLUSH bit set. For real device | ||
57 | drivers that do not have a volatile cache the REQ_FLUSH and REQ_FUA bits | ||
58 | on non-empty bios can simply be ignored, and REQ_FLUSH requests without | ||
59 | data can be completed successfully without doing any work. Drivers for | ||
60 | devices with volatile caches need to implement the support for these | ||
61 | flags themselves without any help from the block layer. | ||
62 | |||
63 | |||
64 | Implementation details for request_fn based block drivers | ||
65 | -------------------------------------------------------------- | ||
66 | |||
67 | For devices that do not support volatile write caches there is no driver | ||
68 | support required, the block layer completes empty REQ_FLUSH requests before | ||
69 | entering the driver and strips off the REQ_FLUSH and REQ_FUA bits from | ||
70 | requests that have a payload. For devices with volatile write caches the | ||
71 | driver needs to tell the block layer that it supports flushing caches by | ||
72 | doing: | ||
73 | |||
74 | blk_queue_flush(sdkp->disk->queue, REQ_FLUSH); | ||
75 | |||
76 | and handle empty REQ_FLUSH requests in its prep_fn/request_fn. Note that | ||
77 | REQ_FLUSH requests with a payload are automatically turned into a sequence | ||
78 | of an empty REQ_FLUSH request followed by the actual write by the block | ||
79 | layer. For devices that also support the FUA bit the block layer needs | ||
80 | to be told to pass through the REQ_FUA bit using: | ||
81 | |||
82 | blk_queue_flush(sdkp->disk->queue, REQ_FLUSH | REQ_FUA); | ||
83 | |||
84 | and the driver must handle write requests that have the REQ_FUA bit set | ||
85 | in prep_fn/request_fn. If the FUA bit is not natively supported the block | ||
86 | layer turns it into an empty REQ_FLUSH request after the actual write. | ||
diff --git a/Documentation/cgroups/blkio-controller.txt b/Documentation/cgroups/blkio-controller.txt index 48e0b21b005..d6da611f8f6 100644 --- a/Documentation/cgroups/blkio-controller.txt +++ b/Documentation/cgroups/blkio-controller.txt | |||
@@ -8,12 +8,17 @@ both at leaf nodes as well as at intermediate nodes in a storage hierarchy. | |||
8 | Plan is to use the same cgroup based management interface for blkio controller | 8 | Plan is to use the same cgroup based management interface for blkio controller |
9 | and based on user options switch IO policies in the background. | 9 | and based on user options switch IO policies in the background. |
10 | 10 | ||
11 | In the first phase, this patchset implements proportional weight time based | 11 | Currently two IO control policies are implemented. First one is proportional |
12 | division of disk policy. It is implemented in CFQ. Hence this policy takes | 12 | weight time based division of disk policy. It is implemented in CFQ. Hence |
13 | effect only on leaf nodes when CFQ is being used. | 13 | this policy takes effect only on leaf nodes when CFQ is being used. The second |
14 | one is throttling policy which can be used to specify upper IO rate limits | ||
15 | on devices. This policy is implemented in generic block layer and can be | ||
16 | used on leaf nodes as well as higher level logical devices like device mapper. | ||
14 | 17 | ||
15 | HOWTO | 18 | HOWTO |
16 | ===== | 19 | ===== |
20 | Proportional Weight division of bandwidth | ||
21 | ----------------------------------------- | ||
17 | You can do a very simple testing of running two dd threads in two different | 22 | You can do a very simple testing of running two dd threads in two different |
18 | cgroups. Here is what you can do. | 23 | cgroups. Here is what you can do. |
19 | 24 | ||
@@ -55,6 +60,35 @@ cgroups. Here is what you can do. | |||
55 | group dispatched to the disk. We provide fairness in terms of disk time, so | 60 | group dispatched to the disk. We provide fairness in terms of disk time, so |
56 | ideally io.disk_time of cgroups should be in proportion to the weight. | 61 | ideally io.disk_time of cgroups should be in proportion to the weight. |
57 | 62 | ||
63 | Throttling/Upper Limit policy | ||
64 | ----------------------------- | ||
65 | - Enable Block IO controller | ||
66 | CONFIG_BLK_CGROUP=y | ||
67 | |||
68 | - Enable throttling in block layer | ||
69 | CONFIG_BLK_DEV_THROTTLING=y | ||
70 | |||
71 | - Mount blkio controller | ||
72 | mount -t cgroup -o blkio none /cgroup/blkio | ||
73 | |||
74 | - Specify a bandwidth rate on particular device for root group. The format | ||
75 | for policy is "<major>:<minor> <byes_per_second>". | ||
76 | |||
77 | echo "8:16 1048576" > /cgroup/blkio/blkio.read_bps_device | ||
78 | |||
79 | Above will put a limit of 1MB/second on reads happening for root group | ||
80 | on device having major/minor number 8:16. | ||
81 | |||
82 | - Run dd to read a file and see if rate is throttled to 1MB/s or not. | ||
83 | |||
84 | # dd if=/mnt/common/zerofile of=/dev/null bs=4K count=1024 | ||
85 | # iflag=direct | ||
86 | 1024+0 records in | ||
87 | 1024+0 records out | ||
88 | 4194304 bytes (4.2 MB) copied, 4.0001 s, 1.0 MB/s | ||
89 | |||
90 | Limits for writes can be put using blkio.write_bps_device file. | ||
91 | |||
58 | Various user visible config options | 92 | Various user visible config options |
59 | =================================== | 93 | =================================== |
60 | CONFIG_BLK_CGROUP | 94 | CONFIG_BLK_CGROUP |
@@ -68,8 +102,13 @@ CONFIG_CFQ_GROUP_IOSCHED | |||
68 | - Enables group scheduling in CFQ. Currently only 1 level of group | 102 | - Enables group scheduling in CFQ. Currently only 1 level of group |
69 | creation is allowed. | 103 | creation is allowed. |
70 | 104 | ||
105 | CONFIG_BLK_DEV_THROTTLING | ||
106 | - Enable block device throttling support in block layer. | ||
107 | |||
71 | Details of cgroup files | 108 | Details of cgroup files |
72 | ======================= | 109 | ======================= |
110 | Proportional weight policy files | ||
111 | -------------------------------- | ||
73 | - blkio.weight | 112 | - blkio.weight |
74 | - Specifies per cgroup weight. This is default weight of the group | 113 | - Specifies per cgroup weight. This is default weight of the group |
75 | on all the devices until and unless overridden by per device rule. | 114 | on all the devices until and unless overridden by per device rule. |
@@ -210,6 +249,67 @@ Details of cgroup files | |||
210 | and minor number of the device and third field specifies the number | 249 | and minor number of the device and third field specifies the number |
211 | of times a group was dequeued from a particular device. | 250 | of times a group was dequeued from a particular device. |
212 | 251 | ||
252 | Throttling/Upper limit policy files | ||
253 | ----------------------------------- | ||
254 | - blkio.throttle.read_bps_device | ||
255 | - Specifies upper limit on READ rate from the device. IO rate is | ||
256 | specified in bytes per second. Rules are per deivce. Following is | ||
257 | the format. | ||
258 | |||
259 | echo "<major>:<minor> <rate_bytes_per_second>" > /cgrp/blkio.read_bps_device | ||
260 | |||
261 | - blkio.throttle.write_bps_device | ||
262 | - Specifies upper limit on WRITE rate to the device. IO rate is | ||
263 | specified in bytes per second. Rules are per deivce. Following is | ||
264 | the format. | ||
265 | |||
266 | echo "<major>:<minor> <rate_bytes_per_second>" > /cgrp/blkio.write_bps_device | ||
267 | |||
268 | - blkio.throttle.read_iops_device | ||
269 | - Specifies upper limit on READ rate from the device. IO rate is | ||
270 | specified in IO per second. Rules are per deivce. Following is | ||
271 | the format. | ||
272 | |||
273 | echo "<major>:<minor> <rate_io_per_second>" > /cgrp/blkio.read_iops_device | ||
274 | |||
275 | - blkio.throttle.write_iops_device | ||
276 | - Specifies upper limit on WRITE rate to the device. IO rate is | ||
277 | specified in io per second. Rules are per deivce. Following is | ||
278 | the format. | ||
279 | |||
280 | echo "<major>:<minor> <rate_io_per_second>" > /cgrp/blkio.write_iops_device | ||
281 | |||
282 | Note: If both BW and IOPS rules are specified for a device, then IO is | ||
283 | subjectd to both the constraints. | ||
284 | |||
285 | - blkio.throttle.io_serviced | ||
286 | - Number of IOs (bio) completed to/from the disk by the group (as | ||
287 | seen by throttling policy). These are further divided by the type | ||
288 | of operation - read or write, sync or async. First two fields specify | ||
289 | the major and minor number of the device, third field specifies the | ||
290 | operation type and the fourth field specifies the number of IOs. | ||
291 | |||
292 | blkio.io_serviced does accounting as seen by CFQ and counts are in | ||
293 | number of requests (struct request). On the other hand, | ||
294 | blkio.throttle.io_serviced counts number of IO in terms of number | ||
295 | of bios as seen by throttling policy. These bios can later be | ||
296 | merged by elevator and total number of requests completed can be | ||
297 | lesser. | ||
298 | |||
299 | - blkio.throttle.io_service_bytes | ||
300 | - Number of bytes transferred to/from the disk by the group. These | ||
301 | are further divided by the type of operation - read or write, sync | ||
302 | or async. First two fields specify the major and minor number of the | ||
303 | device, third field specifies the operation type and the fourth field | ||
304 | specifies the number of bytes. | ||
305 | |||
306 | These numbers should roughly be same as blkio.io_service_bytes as | ||
307 | updated by CFQ. The difference between two is that | ||
308 | blkio.io_service_bytes will not be updated if CFQ is not operating | ||
309 | on request queue. | ||
310 | |||
311 | Common files among various policies | ||
312 | ----------------------------------- | ||
213 | - blkio.reset_stats | 313 | - blkio.reset_stats |
214 | - Writing an int to this file will result in resetting all the stats | 314 | - Writing an int to this file will result in resetting all the stats |
215 | for that cgroup. | 315 | for that cgroup. |
@@ -217,6 +317,7 @@ Details of cgroup files | |||
217 | CFQ sysfs tunable | 317 | CFQ sysfs tunable |
218 | ================= | 318 | ================= |
219 | /sys/block/<disk>/queue/iosched/group_isolation | 319 | /sys/block/<disk>/queue/iosched/group_isolation |
320 | ----------------------------------------------- | ||
220 | 321 | ||
221 | If group_isolation=1, it provides stronger isolation between groups at the | 322 | If group_isolation=1, it provides stronger isolation between groups at the |
222 | expense of throughput. By default group_isolation is 0. In general that | 323 | expense of throughput. By default group_isolation is 0. In general that |
@@ -243,6 +344,33 @@ By default one should run with group_isolation=0. If that is not sufficient | |||
243 | and one wants stronger isolation between groups, then set group_isolation=1 | 344 | and one wants stronger isolation between groups, then set group_isolation=1 |
244 | but this will come at cost of reduced throughput. | 345 | but this will come at cost of reduced throughput. |
245 | 346 | ||
347 | /sys/block/<disk>/queue/iosched/slice_idle | ||
348 | ------------------------------------------ | ||
349 | On a faster hardware CFQ can be slow, especially with sequential workload. | ||
350 | This happens because CFQ idles on a single queue and single queue might not | ||
351 | drive deeper request queue depths to keep the storage busy. In such scenarios | ||
352 | one can try setting slice_idle=0 and that would switch CFQ to IOPS | ||
353 | (IO operations per second) mode on NCQ supporting hardware. | ||
354 | |||
355 | That means CFQ will not idle between cfq queues of a cfq group and hence be | ||
356 | able to driver higher queue depth and achieve better throughput. That also | ||
357 | means that cfq provides fairness among groups in terms of IOPS and not in | ||
358 | terms of disk time. | ||
359 | |||
360 | /sys/block/<disk>/queue/iosched/group_idle | ||
361 | ------------------------------------------ | ||
362 | If one disables idling on individual cfq queues and cfq service trees by | ||
363 | setting slice_idle=0, group_idle kicks in. That means CFQ will still idle | ||
364 | on the group in an attempt to provide fairness among groups. | ||
365 | |||
366 | By default group_idle is same as slice_idle and does not do anything if | ||
367 | slice_idle is enabled. | ||
368 | |||
369 | One can experience an overall throughput drop if you have created multiple | ||
370 | groups and put applications in that group which are not driving enough | ||
371 | IO to keep disk busy. In that case set group_idle=0, and CFQ will not idle | ||
372 | on individual groups and throughput should improve. | ||
373 | |||
246 | What works | 374 | What works |
247 | ========== | 375 | ========== |
248 | - Currently only sync IO queues are support. All the buffered writes are | 376 | - Currently only sync IO queues are support. All the buffered writes are |
diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt index f1c5c4bccd3..902d3151f52 100644 --- a/Documentation/cputopology.txt +++ b/Documentation/cputopology.txt | |||
@@ -14,25 +14,39 @@ to /proc/cpuinfo. | |||
14 | identifier (rather than the kernel's). The actual value is | 14 | identifier (rather than the kernel's). The actual value is |
15 | architecture and platform dependent. | 15 | architecture and platform dependent. |
16 | 16 | ||
17 | 3) /sys/devices/system/cpu/cpuX/topology/thread_siblings: | 17 | 3) /sys/devices/system/cpu/cpuX/topology/book_id: |
18 | |||
19 | the book ID of cpuX. Typically it is the hardware platform's | ||
20 | identifier (rather than the kernel's). The actual value is | ||
21 | architecture and platform dependent. | ||
22 | |||
23 | 4) /sys/devices/system/cpu/cpuX/topology/thread_siblings: | ||
18 | 24 | ||
19 | internel kernel map of cpuX's hardware threads within the same | 25 | internel kernel map of cpuX's hardware threads within the same |
20 | core as cpuX | 26 | core as cpuX |
21 | 27 | ||
22 | 4) /sys/devices/system/cpu/cpuX/topology/core_siblings: | 28 | 5) /sys/devices/system/cpu/cpuX/topology/core_siblings: |
23 | 29 | ||
24 | internal kernel map of cpuX's hardware threads within the same | 30 | internal kernel map of cpuX's hardware threads within the same |
25 | physical_package_id. | 31 | physical_package_id. |
26 | 32 | ||
33 | 6) /sys/devices/system/cpu/cpuX/topology/book_siblings: | ||
34 | |||
35 | internal kernel map of cpuX's hardware threads within the same | ||
36 | book_id. | ||
37 | |||
27 | To implement it in an architecture-neutral way, a new source file, | 38 | To implement it in an architecture-neutral way, a new source file, |
28 | drivers/base/topology.c, is to export the 4 attributes. | 39 | drivers/base/topology.c, is to export the 4 or 6 attributes. The two book |
40 | related sysfs files will only be created if CONFIG_SCHED_BOOK is selected. | ||
29 | 41 | ||
30 | For an architecture to support this feature, it must define some of | 42 | For an architecture to support this feature, it must define some of |
31 | these macros in include/asm-XXX/topology.h: | 43 | these macros in include/asm-XXX/topology.h: |
32 | #define topology_physical_package_id(cpu) | 44 | #define topology_physical_package_id(cpu) |
33 | #define topology_core_id(cpu) | 45 | #define topology_core_id(cpu) |
46 | #define topology_book_id(cpu) | ||
34 | #define topology_thread_cpumask(cpu) | 47 | #define topology_thread_cpumask(cpu) |
35 | #define topology_core_cpumask(cpu) | 48 | #define topology_core_cpumask(cpu) |
49 | #define topology_book_cpumask(cpu) | ||
36 | 50 | ||
37 | The type of **_id is int. | 51 | The type of **_id is int. |
38 | The type of siblings is (const) struct cpumask *. | 52 | The type of siblings is (const) struct cpumask *. |
@@ -45,6 +59,9 @@ not defined by include/asm-XXX/topology.h: | |||
45 | 3) thread_siblings: just the given CPU | 59 | 3) thread_siblings: just the given CPU |
46 | 4) core_siblings: just the given CPU | 60 | 4) core_siblings: just the given CPU |
47 | 61 | ||
62 | For architectures that don't support books (CONFIG_SCHED_BOOK) there are no | ||
63 | default definitions for topology_book_id() and topology_book_cpumask(). | ||
64 | |||
48 | Additionally, CPU topology information is provided under | 65 | Additionally, CPU topology information is provided under |
49 | /sys/devices/system/cpu and includes these files. The internal | 66 | /sys/devices/system/cpu and includes these files. The internal |
50 | source for the output is in brackets ("[]"). | 67 | source for the output is in brackets ("[]"). |
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 842aa9de84a..5e2bc4ab897 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt | |||
@@ -386,34 +386,6 @@ Who: Tejun Heo <tj@kernel.org> | |||
386 | 386 | ||
387 | ---------------------------- | 387 | ---------------------------- |
388 | 388 | ||
389 | What: Support for VMware's guest paravirtuliazation technique [VMI] will be | ||
390 | dropped. | ||
391 | When: 2.6.37 or earlier. | ||
392 | Why: With the recent innovations in CPU hardware acceleration technologies | ||
393 | from Intel and AMD, VMware ran a few experiments to compare these | ||
394 | techniques to guest paravirtualization technique on VMware's platform. | ||
395 | These hardware assisted virtualization techniques have outperformed the | ||
396 | performance benefits provided by VMI in most of the workloads. VMware | ||
397 | expects that these hardware features will be ubiquitous in a couple of | ||
398 | years, as a result, VMware has started a phased retirement of this | ||
399 | feature from the hypervisor. We will be removing this feature from the | ||
400 | Kernel too. Right now we are targeting 2.6.37 but can retire earlier if | ||
401 | technical reasons (read opportunity to remove major chunk of pvops) | ||
402 | arise. | ||
403 | |||
404 | Please note that VMI has always been an optimization and non-VMI kernels | ||
405 | still work fine on VMware's platform. | ||
406 | Latest versions of VMware's product which support VMI are, | ||
407 | Workstation 7.0 and VSphere 4.0 on ESX side, future maintainence | ||
408 | releases for these products will continue supporting VMI. | ||
409 | |||
410 | For more details about VMI retirement take a look at this, | ||
411 | http://blogs.vmware.com/guestosguide/2009/09/vmi-retirement.html | ||
412 | |||
413 | Who: Alok N Kataria <akataria@vmware.com> | ||
414 | |||
415 | ---------------------------- | ||
416 | |||
417 | What: Support for lcd_switch and display_get in asus-laptop driver | 389 | What: Support for lcd_switch and display_get in asus-laptop driver |
418 | When: March 2010 | 390 | When: March 2010 |
419 | Why: These two features use non-standard interfaces. There are the | 391 | Why: These two features use non-standard interfaces. There are the |
diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt index 1f7ae144f6d..5393e661169 100644 --- a/Documentation/filesystems/ocfs2.txt +++ b/Documentation/filesystems/ocfs2.txt | |||
@@ -87,3 +87,10 @@ dir_resv_level= (*) By default, directory reservations will scale with file | |||
87 | reservations - users should rarely need to change this | 87 | reservations - users should rarely need to change this |
88 | value. If allocation reservations are turned off, this | 88 | value. If allocation reservations are turned off, this |
89 | option will have no effect. | 89 | option will have no effect. |
90 | coherency=full (*) Disallow concurrent O_DIRECT writes, cluster inode | ||
91 | lock will be taken to force other nodes drop cache, | ||
92 | therefore full cluster coherency is guaranteed even | ||
93 | for O_DIRECT writes. | ||
94 | coherency=buffered Allow concurrent O_DIRECT writes without EX lock among | ||
95 | nodes, which gains high performance at risk of getting | ||
96 | stale data on other nodes. | ||
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt index d96a6dba574..9633da01ff4 100644 --- a/Documentation/gpio.txt +++ b/Documentation/gpio.txt | |||
@@ -109,17 +109,19 @@ use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders. | |||
109 | 109 | ||
110 | If you want to initialize a structure with an invalid GPIO number, use | 110 | If you want to initialize a structure with an invalid GPIO number, use |
111 | some negative number (perhaps "-EINVAL"); that will never be valid. To | 111 | some negative number (perhaps "-EINVAL"); that will never be valid. To |
112 | test if a number could reference a GPIO, you may use this predicate: | 112 | test if such number from such a structure could reference a GPIO, you |
113 | may use this predicate: | ||
113 | 114 | ||
114 | int gpio_is_valid(int number); | 115 | int gpio_is_valid(int number); |
115 | 116 | ||
116 | A number that's not valid will be rejected by calls which may request | 117 | A number that's not valid will be rejected by calls which may request |
117 | or free GPIOs (see below). Other numbers may also be rejected; for | 118 | or free GPIOs (see below). Other numbers may also be rejected; for |
118 | example, a number might be valid but unused on a given board. | 119 | example, a number might be valid but temporarily unused on a given board. |
119 | |||
120 | Whether a platform supports multiple GPIO controllers is currently a | ||
121 | platform-specific implementation issue. | ||
122 | 120 | ||
121 | Whether a platform supports multiple GPIO controllers is a platform-specific | ||
122 | implementation issue, as are whether that support can leave "holes" in the space | ||
123 | of GPIO numbers, and whether new controllers can be added at runtime. Such issues | ||
124 | can affect things including whether adjacent GPIO numbers are both valid. | ||
123 | 125 | ||
124 | Using GPIOs | 126 | Using GPIOs |
125 | ----------- | 127 | ----------- |
@@ -480,12 +482,16 @@ To support this framework, a platform's Kconfig will "select" either | |||
480 | ARCH_REQUIRE_GPIOLIB or ARCH_WANT_OPTIONAL_GPIOLIB | 482 | ARCH_REQUIRE_GPIOLIB or ARCH_WANT_OPTIONAL_GPIOLIB |
481 | and arrange that its <asm/gpio.h> includes <asm-generic/gpio.h> and defines | 483 | and arrange that its <asm/gpio.h> includes <asm-generic/gpio.h> and defines |
482 | three functions: gpio_get_value(), gpio_set_value(), and gpio_cansleep(). | 484 | three functions: gpio_get_value(), gpio_set_value(), and gpio_cansleep(). |
483 | They may also want to provide a custom value for ARCH_NR_GPIOS. | ||
484 | 485 | ||
485 | ARCH_REQUIRE_GPIOLIB means that the gpio-lib code will always get compiled | 486 | It may also provide a custom value for ARCH_NR_GPIOS, so that it better |
487 | reflects the number of GPIOs in actual use on that platform, without | ||
488 | wasting static table space. (It should count both built-in/SoC GPIOs and | ||
489 | also ones on GPIO expanders. | ||
490 | |||
491 | ARCH_REQUIRE_GPIOLIB means that the gpiolib code will always get compiled | ||
486 | into the kernel on that architecture. | 492 | into the kernel on that architecture. |
487 | 493 | ||
488 | ARCH_WANT_OPTIONAL_GPIOLIB means the gpio-lib code defaults to off and the user | 494 | ARCH_WANT_OPTIONAL_GPIOLIB means the gpiolib code defaults to off and the user |
489 | can enable it and build it into the kernel optionally. | 495 | can enable it and build it into the kernel optionally. |
490 | 496 | ||
491 | If neither of these options are selected, the platform does not support | 497 | If neither of these options are selected, the platform does not support |
diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface index ff45d1f837c..48ceabedf55 100644 --- a/Documentation/hwmon/sysfs-interface +++ b/Documentation/hwmon/sysfs-interface | |||
@@ -91,12 +91,11 @@ name The chip name. | |||
91 | I2C devices get this attribute created automatically. | 91 | I2C devices get this attribute created automatically. |
92 | RO | 92 | RO |
93 | 93 | ||
94 | update_rate The rate at which the chip will update readings. | 94 | update_interval The interval at which the chip will update readings. |
95 | Unit: millisecond | 95 | Unit: millisecond |
96 | RW | 96 | RW |
97 | Some devices have a variable update rate. This attribute | 97 | Some devices have a variable update rate or interval. |
98 | can be used to change the update rate to the desired | 98 | This attribute can be used to change it to the desired value. |
99 | frequency. | ||
100 | 99 | ||
101 | 100 | ||
102 | ************ | 101 | ************ |
diff --git a/Documentation/kernel-doc-nano-HOWTO.txt b/Documentation/kernel-doc-nano-HOWTO.txt index 27a52b35d55..3d8a97747f7 100644 --- a/Documentation/kernel-doc-nano-HOWTO.txt +++ b/Documentation/kernel-doc-nano-HOWTO.txt | |||
@@ -345,5 +345,10 @@ documentation, in <filename>, for the functions listed. | |||
345 | section titled <section title> from <filename>. | 345 | section titled <section title> from <filename>. |
346 | Spaces are allowed in <section title>; do not quote the <section title>. | 346 | Spaces are allowed in <section title>; do not quote the <section title>. |
347 | 347 | ||
348 | !C<filename> is replaced by nothing, but makes the tools check that | ||
349 | all DOC: sections and documented functions, symbols, etc. are used. | ||
350 | This makes sense to use when you use !F/!P only and want to verify | ||
351 | that all documentation is included. | ||
352 | |||
348 | Tim. | 353 | Tim. |
349 | */ <twaugh@redhat.com> | 354 | */ <twaugh@redhat.com> |
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index f084af0cb8e..02f21d9220c 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt | |||
@@ -455,7 +455,7 @@ and is between 256 and 4096 characters. It is defined in the file | |||
455 | [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2, | 455 | [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2, |
456 | pxa_timer,timer3,32k_counter,timer0_1 | 456 | pxa_timer,timer3,32k_counter,timer0_1 |
457 | [AVR32] avr32 | 457 | [AVR32] avr32 |
458 | [X86-32] pit,hpet,tsc,vmi-timer; | 458 | [X86-32] pit,hpet,tsc; |
459 | scx200_hrt on Geode; cyclone on IBM x440 | 459 | scx200_hrt on Geode; cyclone on IBM x440 |
460 | [MIPS] MIPS | 460 | [MIPS] MIPS |
461 | [PARISC] cr16 | 461 | [PARISC] cr16 |
@@ -1974,15 +1974,18 @@ and is between 256 and 4096 characters. It is defined in the file | |||
1974 | force Enable ASPM even on devices that claim not to support it. | 1974 | force Enable ASPM even on devices that claim not to support it. |
1975 | WARNING: Forcing ASPM on may cause system lockups. | 1975 | WARNING: Forcing ASPM on may cause system lockups. |
1976 | 1976 | ||
1977 | pcie_ports= [PCIE] PCIe ports handling: | ||
1978 | auto Ask the BIOS whether or not to use native PCIe services | ||
1979 | associated with PCIe ports (PME, hot-plug, AER). Use | ||
1980 | them only if that is allowed by the BIOS. | ||
1981 | native Use native PCIe services associated with PCIe ports | ||
1982 | unconditionally. | ||
1983 | compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe | ||
1984 | ports driver. | ||
1985 | |||
1977 | pcie_pme= [PCIE,PM] Native PCIe PME signaling options: | 1986 | pcie_pme= [PCIE,PM] Native PCIe PME signaling options: |
1978 | Format: {auto|force}[,nomsi] | ||
1979 | auto Use native PCIe PME signaling if the BIOS allows the | ||
1980 | kernel to control PCIe config registers of root ports. | ||
1981 | force Use native PCIe PME signaling even if the BIOS refuses | ||
1982 | to allow the kernel to control the relevant PCIe config | ||
1983 | registers. | ||
1984 | nomsi Do not use MSI for native PCIe PME signaling (this makes | 1987 | nomsi Do not use MSI for native PCIe PME signaling (this makes |
1985 | all PCIe root ports use INTx for everything). | 1988 | all PCIe root ports use INTx for all services). |
1986 | 1989 | ||
1987 | pcmv= [HW,PCMCIA] BadgePAD 4 | 1990 | pcmv= [HW,PCMCIA] BadgePAD 4 |
1988 | 1991 | ||
@@ -2150,6 +2153,11 @@ and is between 256 and 4096 characters. It is defined in the file | |||
2150 | Reserves a hole at the top of the kernel virtual | 2153 | Reserves a hole at the top of the kernel virtual |
2151 | address space. | 2154 | address space. |
2152 | 2155 | ||
2156 | reservelow= [X86] | ||
2157 | Format: nn[K] | ||
2158 | Set the amount of memory to reserve for BIOS at | ||
2159 | the bottom of the address space. | ||
2160 | |||
2153 | reset_devices [KNL] Force drivers to reset the underlying device | 2161 | reset_devices [KNL] Force drivers to reset the underlying device |
2154 | during initialization. | 2162 | during initialization. |
2155 | 2163 | ||
@@ -2162,6 +2170,11 @@ and is between 256 and 4096 characters. It is defined in the file | |||
2162 | in <PAGE_SIZE> units (needed only for swap files). | 2170 | in <PAGE_SIZE> units (needed only for swap files). |
2163 | See Documentation/power/swsusp-and-swap-files.txt | 2171 | See Documentation/power/swsusp-and-swap-files.txt |
2164 | 2172 | ||
2173 | hibernate= [HIBERNATION] | ||
2174 | noresume Don't check if there's a hibernation image | ||
2175 | present during boot. | ||
2176 | nocompress Don't compress/decompress hibernation images. | ||
2177 | |||
2165 | retain_initrd [RAM] Keep initrd memory after extraction | 2178 | retain_initrd [RAM] Keep initrd memory after extraction |
2166 | 2179 | ||
2167 | rhash_entries= [KNL,NET] | 2180 | rhash_entries= [KNL,NET] |
@@ -2432,6 +2445,10 @@ and is between 256 and 4096 characters. It is defined in the file | |||
2432 | disables clocksource verification at runtime. | 2445 | disables clocksource verification at runtime. |
2433 | Used to enable high-resolution timer mode on older | 2446 | Used to enable high-resolution timer mode on older |
2434 | hardware, and in virtualized environment. | 2447 | hardware, and in virtualized environment. |
2448 | [x86] noirqtime: Do not use TSC to do irq accounting. | ||
2449 | Used to run time disable IRQ_TIME_ACCOUNTING on any | ||
2450 | platforms where RDTSC is slow and this accounting | ||
2451 | can add overhead. | ||
2435 | 2452 | ||
2436 | turbografx.map[2|3]= [HW,JOY] | 2453 | turbografx.map[2|3]= [HW,JOY] |
2437 | TurboGraFX parallel port interface | 2454 | TurboGraFX parallel port interface |
diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt index 1762b81fcdf..741fe66d6ec 100644 --- a/Documentation/kprobes.txt +++ b/Documentation/kprobes.txt | |||
@@ -542,9 +542,11 @@ Kprobes does not use mutexes or allocate memory except during | |||
542 | registration and unregistration. | 542 | registration and unregistration. |
543 | 543 | ||
544 | Probe handlers are run with preemption disabled. Depending on the | 544 | Probe handlers are run with preemption disabled. Depending on the |
545 | architecture, handlers may also run with interrupts disabled. In any | 545 | architecture and optimization state, handlers may also run with |
546 | case, your handler should not yield the CPU (e.g., by attempting to | 546 | interrupts disabled (e.g., kretprobe handlers and optimized kprobe |
547 | acquire a semaphore). | 547 | handlers run without interrupt disabled on x86/x86-64). In any case, |
548 | your handler should not yield the CPU (e.g., by attempting to acquire | ||
549 | a semaphore). | ||
548 | 550 | ||
549 | Since a return probe is implemented by replacing the return | 551 | Since a return probe is implemented by replacing the return |
550 | address with the trampoline's address, stack backtraces and calls | 552 | address with the trampoline's address, stack backtraces and calls |
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 8a6a8c6d498..dc73bc54cc4 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c | |||
@@ -1640,15 +1640,6 @@ static void blk_request(struct virtqueue *vq) | |||
1640 | off = out->sector * 512; | 1640 | off = out->sector * 512; |
1641 | 1641 | ||
1642 | /* | 1642 | /* |
1643 | * The block device implements "barriers", where the Guest indicates | ||
1644 | * that it wants all previous writes to occur before this write. We | ||
1645 | * don't have a way of asking our kernel to do a barrier, so we just | ||
1646 | * synchronize all the data in the file. Pretty poor, no? | ||
1647 | */ | ||
1648 | if (out->type & VIRTIO_BLK_T_BARRIER) | ||
1649 | fdatasync(vblk->fd); | ||
1650 | |||
1651 | /* | ||
1652 | * In general the virtio block driver is allowed to try SCSI commands. | 1643 | * In general the virtio block driver is allowed to try SCSI commands. |
1653 | * It'd be nice if we supported eject, for example, but we don't. | 1644 | * It'd be nice if we supported eject, for example, but we don't. |
1654 | */ | 1645 | */ |
@@ -1680,6 +1671,13 @@ static void blk_request(struct virtqueue *vq) | |||
1680 | /* Die, bad Guest, die. */ | 1671 | /* Die, bad Guest, die. */ |
1681 | errx(1, "Write past end %llu+%u", off, ret); | 1672 | errx(1, "Write past end %llu+%u", off, ret); |
1682 | } | 1673 | } |
1674 | |||
1675 | wlen = sizeof(*in); | ||
1676 | *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); | ||
1677 | } else if (out->type & VIRTIO_BLK_T_FLUSH) { | ||
1678 | /* Flush */ | ||
1679 | ret = fdatasync(vblk->fd); | ||
1680 | verbose("FLUSH fdatasync: %i\n", ret); | ||
1683 | wlen = sizeof(*in); | 1681 | wlen = sizeof(*in); |
1684 | *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); | 1682 | *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); |
1685 | } else { | 1683 | } else { |
@@ -1703,15 +1701,6 @@ static void blk_request(struct virtqueue *vq) | |||
1703 | } | 1701 | } |
1704 | } | 1702 | } |
1705 | 1703 | ||
1706 | /* | ||
1707 | * OK, so we noted that it was pretty poor to use an fdatasync as a | ||
1708 | * barrier. But Christoph Hellwig points out that we need a sync | ||
1709 | * *afterwards* as well: "Barriers specify no reordering to the front | ||
1710 | * or the back." And Jens Axboe confirmed it, so here we are: | ||
1711 | */ | ||
1712 | if (out->type & VIRTIO_BLK_T_BARRIER) | ||
1713 | fdatasync(vblk->fd); | ||
1714 | |||
1715 | /* Finished that request. */ | 1704 | /* Finished that request. */ |
1716 | add_used(vq, head, wlen); | 1705 | add_used(vq, head, wlen); |
1717 | } | 1706 | } |
@@ -1736,8 +1725,8 @@ static void setup_block_file(const char *filename) | |||
1736 | vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE); | 1725 | vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE); |
1737 | vblk->len = lseek64(vblk->fd, 0, SEEK_END); | 1726 | vblk->len = lseek64(vblk->fd, 0, SEEK_END); |
1738 | 1727 | ||
1739 | /* We support barriers. */ | 1728 | /* We support FLUSH. */ |
1740 | add_feature(dev, VIRTIO_BLK_F_BARRIER); | 1729 | add_feature(dev, VIRTIO_BLK_F_FLUSH); |
1741 | 1730 | ||
1742 | /* Tell Guest how many sectors this device has. */ | 1731 | /* Tell Guest how many sectors this device has. */ |
1743 | conf.capacity = cpu_to_le64(vblk->len / 512); | 1732 | conf.capacity = cpu_to_le64(vblk->len / 512); |
diff --git a/Documentation/mutex-design.txt b/Documentation/mutex-design.txt index c91ccc0720f..38c10fd7f41 100644 --- a/Documentation/mutex-design.txt +++ b/Documentation/mutex-design.txt | |||
@@ -9,7 +9,7 @@ firstly, there's nothing wrong with semaphores. But if the simpler | |||
9 | mutex semantics are sufficient for your code, then there are a couple | 9 | mutex semantics are sufficient for your code, then there are a couple |
10 | of advantages of mutexes: | 10 | of advantages of mutexes: |
11 | 11 | ||
12 | - 'struct mutex' is smaller on most architectures: .e.g on x86, | 12 | - 'struct mutex' is smaller on most architectures: E.g. on x86, |
13 | 'struct semaphore' is 20 bytes, 'struct mutex' is 16 bytes. | 13 | 'struct semaphore' is 20 bytes, 'struct mutex' is 16 bytes. |
14 | A smaller structure size means less RAM footprint, and better | 14 | A smaller structure size means less RAM footprint, and better |
15 | CPU-cache utilization. | 15 | CPU-cache utilization. |
@@ -136,3 +136,4 @@ the APIs of 'struct mutex' have been streamlined: | |||
136 | void mutex_lock_nested(struct mutex *lock, unsigned int subclass); | 136 | void mutex_lock_nested(struct mutex *lock, unsigned int subclass); |
137 | int mutex_lock_interruptible_nested(struct mutex *lock, | 137 | int mutex_lock_interruptible_nested(struct mutex *lock, |
138 | unsigned int subclass); | 138 | unsigned int subclass); |
139 | int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock); | ||
diff --git a/Documentation/networking/e1000.txt b/Documentation/networking/e1000.txt index 2df71861e57..d9271e74e48 100644 --- a/Documentation/networking/e1000.txt +++ b/Documentation/networking/e1000.txt | |||
@@ -1,82 +1,35 @@ | |||
1 | Linux* Base Driver for the Intel(R) PRO/1000 Family of Adapters | 1 | Linux* Base Driver for the Intel(R) PRO/1000 Family of Adapters |
2 | =============================================================== | 2 | =============================================================== |
3 | 3 | ||
4 | September 26, 2006 | 4 | Intel Gigabit Linux driver. |
5 | 5 | Copyright(c) 1999 - 2010 Intel Corporation. | |
6 | 6 | ||
7 | Contents | 7 | Contents |
8 | ======== | 8 | ======== |
9 | 9 | ||
10 | - In This Release | ||
11 | - Identifying Your Adapter | 10 | - Identifying Your Adapter |
12 | - Building and Installation | ||
13 | - Command Line Parameters | 11 | - Command Line Parameters |
14 | - Speed and Duplex Configuration | 12 | - Speed and Duplex Configuration |
15 | - Additional Configurations | 13 | - Additional Configurations |
16 | - Known Issues | ||
17 | - Support | 14 | - Support |
18 | 15 | ||
19 | |||
20 | In This Release | ||
21 | =============== | ||
22 | |||
23 | This file describes the Linux* Base Driver for the Intel(R) PRO/1000 Family | ||
24 | of Adapters. This driver includes support for Itanium(R)2-based systems. | ||
25 | |||
26 | For questions related to hardware requirements, refer to the documentation | ||
27 | supplied with your Intel PRO/1000 adapter. All hardware requirements listed | ||
28 | apply to use with Linux. | ||
29 | |||
30 | The following features are now available in supported kernels: | ||
31 | - Native VLANs | ||
32 | - Channel Bonding (teaming) | ||
33 | - SNMP | ||
34 | |||
35 | Channel Bonding documentation can be found in the Linux kernel source: | ||
36 | /Documentation/networking/bonding.txt | ||
37 | |||
38 | The driver information previously displayed in the /proc filesystem is not | ||
39 | supported in this release. Alternatively, you can use ethtool (version 1.6 | ||
40 | or later), lspci, and ifconfig to obtain the same information. | ||
41 | |||
42 | Instructions on updating ethtool can be found in the section "Additional | ||
43 | Configurations" later in this document. | ||
44 | |||
45 | NOTE: The Intel(R) 82562v 10/100 Network Connection only provides 10/100 | ||
46 | support. | ||
47 | |||
48 | |||
49 | Identifying Your Adapter | 16 | Identifying Your Adapter |
50 | ======================== | 17 | ======================== |
51 | 18 | ||
52 | For more information on how to identify your adapter, go to the Adapter & | 19 | For more information on how to identify your adapter, go to the Adapter & |
53 | Driver ID Guide at: | 20 | Driver ID Guide at: |
54 | 21 | ||
55 | http://support.intel.com/support/network/adapter/pro100/21397.htm | 22 | http://support.intel.com/support/go/network/adapter/idguide.htm |
56 | 23 | ||
57 | For the latest Intel network drivers for Linux, refer to the following | 24 | For the latest Intel network drivers for Linux, refer to the following |
58 | website. In the search field, enter your adapter name or type, or use the | 25 | website. In the search field, enter your adapter name or type, or use the |
59 | networking link on the left to search for your adapter: | 26 | networking link on the left to search for your adapter: |
60 | 27 | ||
61 | http://downloadfinder.intel.com/scripts-df/support_intel.asp | 28 | http://support.intel.com/support/go/network/adapter/home.htm |
62 | |||
63 | 29 | ||
64 | Command Line Parameters | 30 | Command Line Parameters |
65 | ======================= | 31 | ======================= |
66 | 32 | ||
67 | If the driver is built as a module, the following optional parameters | ||
68 | are used by entering them on the command line with the modprobe command | ||
69 | using this syntax: | ||
70 | |||
71 | modprobe e1000 [<option>=<VAL1>,<VAL2>,...] | ||
72 | |||
73 | For example, with two PRO/1000 PCI adapters, entering: | ||
74 | |||
75 | modprobe e1000 TxDescriptors=80,128 | ||
76 | |||
77 | loads the e1000 driver with 80 TX descriptors for the first adapter and | ||
78 | 128 TX descriptors for the second adapter. | ||
79 | |||
80 | The default value for each parameter is generally the recommended setting, | 33 | The default value for each parameter is generally the recommended setting, |
81 | unless otherwise noted. | 34 | unless otherwise noted. |
82 | 35 | ||
@@ -89,10 +42,6 @@ NOTES: For more information about the AutoNeg, Duplex, and Speed | |||
89 | parameters, see the application note at: | 42 | parameters, see the application note at: |
90 | http://www.intel.com/design/network/applnots/ap450.htm | 43 | http://www.intel.com/design/network/applnots/ap450.htm |
91 | 44 | ||
92 | A descriptor describes a data buffer and attributes related to | ||
93 | the data buffer. This information is accessed by the hardware. | ||
94 | |||
95 | |||
96 | AutoNeg | 45 | AutoNeg |
97 | ------- | 46 | ------- |
98 | (Supported only on adapters with copper connections) | 47 | (Supported only on adapters with copper connections) |
@@ -106,7 +55,6 @@ Duplex parameters must not be specified. | |||
106 | NOTE: Refer to the Speed and Duplex section of this readme for more | 55 | NOTE: Refer to the Speed and Duplex section of this readme for more |
107 | information on the AutoNeg parameter. | 56 | information on the AutoNeg parameter. |
108 | 57 | ||
109 | |||
110 | Duplex | 58 | Duplex |
111 | ------ | 59 | ------ |
112 | (Supported only on adapters with copper connections) | 60 | (Supported only on adapters with copper connections) |
@@ -119,7 +67,6 @@ set to auto-negotiate, the board auto-detects the correct duplex. If the | |||
119 | link partner is forced (either full or half), Duplex defaults to half- | 67 | link partner is forced (either full or half), Duplex defaults to half- |
120 | duplex. | 68 | duplex. |
121 | 69 | ||
122 | |||
123 | FlowControl | 70 | FlowControl |
124 | ----------- | 71 | ----------- |
125 | Valid Range: 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx) | 72 | Valid Range: 0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx) |
@@ -128,16 +75,16 @@ Default Value: Reads flow control settings from the EEPROM | |||
128 | This parameter controls the automatic generation(Tx) and response(Rx) | 75 | This parameter controls the automatic generation(Tx) and response(Rx) |
129 | to Ethernet PAUSE frames. | 76 | to Ethernet PAUSE frames. |
130 | 77 | ||
131 | |||
132 | InterruptThrottleRate | 78 | InterruptThrottleRate |
133 | --------------------- | 79 | --------------------- |
134 | (not supported on Intel(R) 82542, 82543 or 82544-based adapters) | 80 | (not supported on Intel(R) 82542, 82543 or 82544-based adapters) |
135 | Valid Range: 0,1,3,100-100000 (0=off, 1=dynamic, 3=dynamic conservative) | 81 | Valid Range: 0,1,3,4,100-100000 (0=off, 1=dynamic, 3=dynamic conservative, |
82 | 4=simplified balancing) | ||
136 | Default Value: 3 | 83 | Default Value: 3 |
137 | 84 | ||
138 | The driver can limit the amount of interrupts per second that the adapter | 85 | The driver can limit the amount of interrupts per second that the adapter |
139 | will generate for incoming packets. It does this by writing a value to the | 86 | will generate for incoming packets. It does this by writing a value to the |
140 | adapter that is based on the maximum amount of interrupts that the adapter | 87 | adapter that is based on the maximum amount of interrupts that the adapter |
141 | will generate per second. | 88 | will generate per second. |
142 | 89 | ||
143 | Setting InterruptThrottleRate to a value greater or equal to 100 | 90 | Setting InterruptThrottleRate to a value greater or equal to 100 |
@@ -146,37 +93,43 @@ per second, even if more packets have come in. This reduces interrupt | |||
146 | load on the system and can lower CPU utilization under heavy load, | 93 | load on the system and can lower CPU utilization under heavy load, |
147 | but will increase latency as packets are not processed as quickly. | 94 | but will increase latency as packets are not processed as quickly. |
148 | 95 | ||
149 | The default behaviour of the driver previously assumed a static | 96 | The default behaviour of the driver previously assumed a static |
150 | InterruptThrottleRate value of 8000, providing a good fallback value for | 97 | InterruptThrottleRate value of 8000, providing a good fallback value for |
151 | all traffic types,but lacking in small packet performance and latency. | 98 | all traffic types,but lacking in small packet performance and latency. |
152 | The hardware can handle many more small packets per second however, and | 99 | The hardware can handle many more small packets per second however, and |
153 | for this reason an adaptive interrupt moderation algorithm was implemented. | 100 | for this reason an adaptive interrupt moderation algorithm was implemented. |
154 | 101 | ||
155 | Since 7.3.x, the driver has two adaptive modes (setting 1 or 3) in which | 102 | Since 7.3.x, the driver has two adaptive modes (setting 1 or 3) in which |
156 | it dynamically adjusts the InterruptThrottleRate value based on the traffic | 103 | it dynamically adjusts the InterruptThrottleRate value based on the traffic |
157 | that it receives. After determining the type of incoming traffic in the last | 104 | that it receives. After determining the type of incoming traffic in the last |
158 | timeframe, it will adjust the InterruptThrottleRate to an appropriate value | 105 | timeframe, it will adjust the InterruptThrottleRate to an appropriate value |
159 | for that traffic. | 106 | for that traffic. |
160 | 107 | ||
161 | The algorithm classifies the incoming traffic every interval into | 108 | The algorithm classifies the incoming traffic every interval into |
162 | classes. Once the class is determined, the InterruptThrottleRate value is | 109 | classes. Once the class is determined, the InterruptThrottleRate value is |
163 | adjusted to suit that traffic type the best. There are three classes defined: | 110 | adjusted to suit that traffic type the best. There are three classes defined: |
164 | "Bulk traffic", for large amounts of packets of normal size; "Low latency", | 111 | "Bulk traffic", for large amounts of packets of normal size; "Low latency", |
165 | for small amounts of traffic and/or a significant percentage of small | 112 | for small amounts of traffic and/or a significant percentage of small |
166 | packets; and "Lowest latency", for almost completely small packets or | 113 | packets; and "Lowest latency", for almost completely small packets or |
167 | minimal traffic. | 114 | minimal traffic. |
168 | 115 | ||
169 | In dynamic conservative mode, the InterruptThrottleRate value is set to 4000 | 116 | In dynamic conservative mode, the InterruptThrottleRate value is set to 4000 |
170 | for traffic that falls in class "Bulk traffic". If traffic falls in the "Low | 117 | for traffic that falls in class "Bulk traffic". If traffic falls in the "Low |
171 | latency" or "Lowest latency" class, the InterruptThrottleRate is increased | 118 | latency" or "Lowest latency" class, the InterruptThrottleRate is increased |
172 | stepwise to 20000. This default mode is suitable for most applications. | 119 | stepwise to 20000. This default mode is suitable for most applications. |
173 | 120 | ||
174 | For situations where low latency is vital such as cluster or | 121 | For situations where low latency is vital such as cluster or |
175 | grid computing, the algorithm can reduce latency even more when | 122 | grid computing, the algorithm can reduce latency even more when |
176 | InterruptThrottleRate is set to mode 1. In this mode, which operates | 123 | InterruptThrottleRate is set to mode 1. In this mode, which operates |
177 | the same as mode 3, the InterruptThrottleRate will be increased stepwise to | 124 | the same as mode 3, the InterruptThrottleRate will be increased stepwise to |
178 | 70000 for traffic in class "Lowest latency". | 125 | 70000 for traffic in class "Lowest latency". |
179 | 126 | ||
127 | In simplified mode the interrupt rate is based on the ratio of Tx and | ||
128 | Rx traffic. If the bytes per second rate is approximately equal, the | ||
129 | interrupt rate will drop as low as 2000 interrupts per second. If the | ||
130 | traffic is mostly transmit or mostly receive, the interrupt rate could | ||
131 | be as high as 8000. | ||
132 | |||
180 | Setting InterruptThrottleRate to 0 turns off any interrupt moderation | 133 | Setting InterruptThrottleRate to 0 turns off any interrupt moderation |
181 | and may improve small packet latency, but is generally not suitable | 134 | and may improve small packet latency, but is generally not suitable |
182 | for bulk throughput traffic. | 135 | for bulk throughput traffic. |
@@ -212,8 +165,6 @@ NOTE: When e1000 is loaded with default settings and multiple adapters | |||
212 | be platform-specific. If CPU utilization is not a concern, use | 165 | be platform-specific. If CPU utilization is not a concern, use |
213 | RX_POLLING (NAPI) and default driver settings. | 166 | RX_POLLING (NAPI) and default driver settings. |
214 | 167 | ||
215 | |||
216 | |||
217 | RxDescriptors | 168 | RxDescriptors |
218 | ------------- | 169 | ------------- |
219 | Valid Range: 80-256 for 82542 and 82543-based adapters | 170 | Valid Range: 80-256 for 82542 and 82543-based adapters |
@@ -225,15 +176,14 @@ by the driver. Increasing this value allows the driver to buffer more | |||
225 | incoming packets, at the expense of increased system memory utilization. | 176 | incoming packets, at the expense of increased system memory utilization. |
226 | 177 | ||
227 | Each descriptor is 16 bytes. A receive buffer is also allocated for each | 178 | Each descriptor is 16 bytes. A receive buffer is also allocated for each |
228 | descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending | 179 | descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending |
229 | on the MTU setting. The maximum MTU size is 16110. | 180 | on the MTU setting. The maximum MTU size is 16110. |
230 | 181 | ||
231 | NOTE: MTU designates the frame size. It only needs to be set for Jumbo | 182 | NOTE: MTU designates the frame size. It only needs to be set for Jumbo |
232 | Frames. Depending on the available system resources, the request | 183 | Frames. Depending on the available system resources, the request |
233 | for a higher number of receive descriptors may be denied. In this | 184 | for a higher number of receive descriptors may be denied. In this |
234 | case, use a lower number. | 185 | case, use a lower number. |
235 | 186 | ||
236 | |||
237 | RxIntDelay | 187 | RxIntDelay |
238 | ---------- | 188 | ---------- |
239 | Valid Range: 0-65535 (0=off) | 189 | Valid Range: 0-65535 (0=off) |
@@ -254,7 +204,6 @@ CAUTION: When setting RxIntDelay to a value other than 0, adapters may | |||
254 | restoring the network connection. To eliminate the potential | 204 | restoring the network connection. To eliminate the potential |
255 | for the hang ensure that RxIntDelay is set to 0. | 205 | for the hang ensure that RxIntDelay is set to 0. |
256 | 206 | ||
257 | |||
258 | RxAbsIntDelay | 207 | RxAbsIntDelay |
259 | ------------- | 208 | ------------- |
260 | (This parameter is supported only on 82540, 82545 and later adapters.) | 209 | (This parameter is supported only on 82540, 82545 and later adapters.) |
@@ -268,7 +217,6 @@ packet is received within the set amount of time. Proper tuning, | |||
268 | along with RxIntDelay, may improve traffic throughput in specific network | 217 | along with RxIntDelay, may improve traffic throughput in specific network |
269 | conditions. | 218 | conditions. |
270 | 219 | ||
271 | |||
272 | Speed | 220 | Speed |
273 | ----- | 221 | ----- |
274 | (This parameter is supported only on adapters with copper connections.) | 222 | (This parameter is supported only on adapters with copper connections.) |
@@ -280,7 +228,6 @@ Speed forces the line speed to the specified value in megabits per second | |||
280 | partner is set to auto-negotiate, the board will auto-detect the correct | 228 | partner is set to auto-negotiate, the board will auto-detect the correct |
281 | speed. Duplex should also be set when Speed is set to either 10 or 100. | 229 | speed. Duplex should also be set when Speed is set to either 10 or 100. |
282 | 230 | ||
283 | |||
284 | TxDescriptors | 231 | TxDescriptors |
285 | ------------- | 232 | ------------- |
286 | Valid Range: 80-256 for 82542 and 82543-based adapters | 233 | Valid Range: 80-256 for 82542 and 82543-based adapters |
@@ -295,6 +242,36 @@ NOTE: Depending on the available system resources, the request for a | |||
295 | higher number of transmit descriptors may be denied. In this case, | 242 | higher number of transmit descriptors may be denied. In this case, |
296 | use a lower number. | 243 | use a lower number. |
297 | 244 | ||
245 | TxDescriptorStep | ||
246 | ---------------- | ||
247 | Valid Range: 1 (use every Tx Descriptor) | ||
248 | 4 (use every 4th Tx Descriptor) | ||
249 | |||
250 | Default Value: 1 (use every Tx Descriptor) | ||
251 | |||
252 | On certain non-Intel architectures, it has been observed that intense TX | ||
253 | traffic bursts of short packets may result in an improper descriptor | ||
254 | writeback. If this occurs, the driver will report a "TX Timeout" and reset | ||
255 | the adapter, after which the transmit flow will restart, though data may | ||
256 | have stalled for as much as 10 seconds before it resumes. | ||
257 | |||
258 | The improper writeback does not occur on the first descriptor in a system | ||
259 | memory cache-line, which is typically 32 bytes, or 4 descriptors long. | ||
260 | |||
261 | Setting TxDescriptorStep to a value of 4 will ensure that all TX descriptors | ||
262 | are aligned to the start of a system memory cache line, and so this problem | ||
263 | will not occur. | ||
264 | |||
265 | NOTES: Setting TxDescriptorStep to 4 effectively reduces the number of | ||
266 | TxDescriptors available for transmits to 1/4 of the normal allocation. | ||
267 | This has a possible negative performance impact, which may be | ||
268 | compensated for by allocating more descriptors using the TxDescriptors | ||
269 | module parameter. | ||
270 | |||
271 | There are other conditions which may result in "TX Timeout", which will | ||
272 | not be resolved by the use of the TxDescriptorStep parameter. As the | ||
273 | issue addressed by this parameter has never been observed on Intel | ||
274 | Architecture platforms, it should not be used on Intel platforms. | ||
298 | 275 | ||
299 | TxIntDelay | 276 | TxIntDelay |
300 | ---------- | 277 | ---------- |
@@ -307,7 +284,6 @@ efficiency if properly tuned for specific network traffic. If the | |||
307 | system is reporting dropped transmits, this value may be set too high | 284 | system is reporting dropped transmits, this value may be set too high |
308 | causing the driver to run out of available transmit descriptors. | 285 | causing the driver to run out of available transmit descriptors. |
309 | 286 | ||
310 | |||
311 | TxAbsIntDelay | 287 | TxAbsIntDelay |
312 | ------------- | 288 | ------------- |
313 | (This parameter is supported only on 82540, 82545 and later adapters.) | 289 | (This parameter is supported only on 82540, 82545 and later adapters.) |
@@ -330,6 +306,35 @@ Default Value: 1 | |||
330 | A value of '1' indicates that the driver should enable IP checksum | 306 | A value of '1' indicates that the driver should enable IP checksum |
331 | offload for received packets (both UDP and TCP) to the adapter hardware. | 307 | offload for received packets (both UDP and TCP) to the adapter hardware. |
332 | 308 | ||
309 | Copybreak | ||
310 | --------- | ||
311 | Valid Range: 0-xxxxxxx (0=off) | ||
312 | Default Value: 256 | ||
313 | Usage: insmod e1000.ko copybreak=128 | ||
314 | |||
315 | Driver copies all packets below or equaling this size to a fresh Rx | ||
316 | buffer before handing it up the stack. | ||
317 | |||
318 | This parameter is different than other parameters, in that it is a | ||
319 | single (not 1,1,1 etc.) parameter applied to all driver instances and | ||
320 | it is also available during runtime at | ||
321 | /sys/module/e1000/parameters/copybreak | ||
322 | |||
323 | SmartPowerDownEnable | ||
324 | -------------------- | ||
325 | Valid Range: 0-1 | ||
326 | Default Value: 0 (disabled) | ||
327 | |||
328 | Allows PHY to turn off in lower power states. The user can turn off | ||
329 | this parameter in supported chipsets. | ||
330 | |||
331 | KumeranLockLoss | ||
332 | --------------- | ||
333 | Valid Range: 0-1 | ||
334 | Default Value: 1 (enabled) | ||
335 | |||
336 | This workaround skips resetting the PHY at shutdown for the initial | ||
337 | silicon releases of ICH8 systems. | ||
333 | 338 | ||
334 | Speed and Duplex Configuration | 339 | Speed and Duplex Configuration |
335 | ============================== | 340 | ============================== |
@@ -385,40 +390,9 @@ If the link partner is forced to a specific speed and duplex, then this | |||
385 | parameter should not be used. Instead, use the Speed and Duplex parameters | 390 | parameter should not be used. Instead, use the Speed and Duplex parameters |
386 | previously mentioned to force the adapter to the same speed and duplex. | 391 | previously mentioned to force the adapter to the same speed and duplex. |
387 | 392 | ||
388 | |||
389 | Additional Configurations | 393 | Additional Configurations |
390 | ========================= | 394 | ========================= |
391 | 395 | ||
392 | Configuring the Driver on Different Distributions | ||
393 | ------------------------------------------------- | ||
394 | Configuring a network driver to load properly when the system is started | ||
395 | is distribution dependent. Typically, the configuration process involves | ||
396 | adding an alias line to /etc/modules.conf or /etc/modprobe.conf as well | ||
397 | as editing other system startup scripts and/or configuration files. Many | ||
398 | popular Linux distributions ship with tools to make these changes for you. | ||
399 | To learn the proper way to configure a network device for your system, | ||
400 | refer to your distribution documentation. If during this process you are | ||
401 | asked for the driver or module name, the name for the Linux Base Driver | ||
402 | for the Intel(R) PRO/1000 Family of Adapters is e1000. | ||
403 | |||
404 | As an example, if you install the e1000 driver for two PRO/1000 adapters | ||
405 | (eth0 and eth1) and set the speed and duplex to 10full and 100half, add | ||
406 | the following to modules.conf or or modprobe.conf: | ||
407 | |||
408 | alias eth0 e1000 | ||
409 | alias eth1 e1000 | ||
410 | options e1000 Speed=10,100 Duplex=2,1 | ||
411 | |||
412 | Viewing Link Messages | ||
413 | --------------------- | ||
414 | Link messages will not be displayed to the console if the distribution is | ||
415 | restricting system messages. In order to see network driver link messages | ||
416 | on your console, set dmesg to eight by entering the following: | ||
417 | |||
418 | dmesg -n 8 | ||
419 | |||
420 | NOTE: This setting is not saved across reboots. | ||
421 | |||
422 | Jumbo Frames | 396 | Jumbo Frames |
423 | ------------ | 397 | ------------ |
424 | Jumbo Frames support is enabled by changing the MTU to a value larger than | 398 | Jumbo Frames support is enabled by changing the MTU to a value larger than |
@@ -437,9 +411,11 @@ Additional Configurations | |||
437 | setting in a different location. | 411 | setting in a different location. |
438 | 412 | ||
439 | Notes: | 413 | Notes: |
440 | 414 | Degradation in throughput performance may be observed in some Jumbo frames | |
441 | - To enable Jumbo Frames, increase the MTU size on the interface beyond | 415 | environments. If this is observed, increasing the application's socket buffer |
442 | 1500. | 416 | size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help. |
417 | See the specific application manual and /usr/src/linux*/Documentation/ | ||
418 | networking/ip-sysctl.txt for more details. | ||
443 | 419 | ||
444 | - The maximum MTU setting for Jumbo Frames is 16110. This value coincides | 420 | - The maximum MTU setting for Jumbo Frames is 16110. This value coincides |
445 | with the maximum Jumbo Frames size of 16128. | 421 | with the maximum Jumbo Frames size of 16128. |
@@ -447,40 +423,11 @@ Additional Configurations | |||
447 | - Using Jumbo Frames at 10 or 100 Mbps may result in poor performance or | 423 | - Using Jumbo Frames at 10 or 100 Mbps may result in poor performance or |
448 | loss of link. | 424 | loss of link. |
449 | 425 | ||
450 | - Some Intel gigabit adapters that support Jumbo Frames have a frame size | ||
451 | limit of 9238 bytes, with a corresponding MTU size limit of 9216 bytes. | ||
452 | The adapters with this limitation are based on the Intel(R) 82571EB, | ||
453 | 82572EI, 82573L and 80003ES2LAN controller. These correspond to the | ||
454 | following product names: | ||
455 | Intel(R) PRO/1000 PT Server Adapter | ||
456 | Intel(R) PRO/1000 PT Desktop Adapter | ||
457 | Intel(R) PRO/1000 PT Network Connection | ||
458 | Intel(R) PRO/1000 PT Dual Port Server Adapter | ||
459 | Intel(R) PRO/1000 PT Dual Port Network Connection | ||
460 | Intel(R) PRO/1000 PF Server Adapter | ||
461 | Intel(R) PRO/1000 PF Network Connection | ||
462 | Intel(R) PRO/1000 PF Dual Port Server Adapter | ||
463 | Intel(R) PRO/1000 PB Server Connection | ||
464 | Intel(R) PRO/1000 PL Network Connection | ||
465 | Intel(R) PRO/1000 EB Network Connection with I/O Acceleration | ||
466 | Intel(R) PRO/1000 EB Backplane Connection with I/O Acceleration | ||
467 | Intel(R) PRO/1000 PT Quad Port Server Adapter | ||
468 | |||
469 | - Adapters based on the Intel(R) 82542 and 82573V/E controller do not | 426 | - Adapters based on the Intel(R) 82542 and 82573V/E controller do not |
470 | support Jumbo Frames. These correspond to the following product names: | 427 | support Jumbo Frames. These correspond to the following product names: |
471 | Intel(R) PRO/1000 Gigabit Server Adapter | 428 | Intel(R) PRO/1000 Gigabit Server Adapter |
472 | Intel(R) PRO/1000 PM Network Connection | 429 | Intel(R) PRO/1000 PM Network Connection |
473 | 430 | ||
474 | - The following adapters do not support Jumbo Frames: | ||
475 | Intel(R) 82562V 10/100 Network Connection | ||
476 | Intel(R) 82566DM Gigabit Network Connection | ||
477 | Intel(R) 82566DC Gigabit Network Connection | ||
478 | Intel(R) 82566MM Gigabit Network Connection | ||
479 | Intel(R) 82566MC Gigabit Network Connection | ||
480 | Intel(R) 82562GT 10/100 Network Connection | ||
481 | Intel(R) 82562G 10/100 Network Connection | ||
482 | |||
483 | |||
484 | Ethtool | 431 | Ethtool |
485 | ------- | 432 | ------- |
486 | The driver utilizes the ethtool interface for driver configuration and | 433 | The driver utilizes the ethtool interface for driver configuration and |
@@ -490,142 +437,14 @@ Additional Configurations | |||
490 | The latest release of ethtool can be found from | 437 | The latest release of ethtool can be found from |
491 | http://sourceforge.net/projects/gkernel. | 438 | http://sourceforge.net/projects/gkernel. |
492 | 439 | ||
493 | NOTE: Ethtool 1.6 only supports a limited set of ethtool options. Support | ||
494 | for a more complete ethtool feature set can be enabled by upgrading | ||
495 | ethtool to ethtool-1.8.1. | ||
496 | |||
497 | Enabling Wake on LAN* (WoL) | 440 | Enabling Wake on LAN* (WoL) |
498 | --------------------------- | 441 | --------------------------- |
499 | WoL is configured through the Ethtool* utility. Ethtool is included with | 442 | WoL is configured through the Ethtool* utility. |
500 | all versions of Red Hat after Red Hat 7.2. For other Linux distributions, | ||
501 | download and install Ethtool from the following website: | ||
502 | http://sourceforge.net/projects/gkernel. | ||
503 | |||
504 | For instructions on enabling WoL with Ethtool, refer to the website listed | ||
505 | above. | ||
506 | 443 | ||
507 | WoL will be enabled on the system during the next shut down or reboot. | 444 | WoL will be enabled on the system during the next shut down or reboot. |
508 | For this driver version, in order to enable WoL, the e1000 driver must be | 445 | For this driver version, in order to enable WoL, the e1000 driver must be |
509 | loaded when shutting down or rebooting the system. | 446 | loaded when shutting down or rebooting the system. |
510 | 447 | ||
511 | Wake On LAN is only supported on port A for the following devices: | ||
512 | Intel(R) PRO/1000 PT Dual Port Network Connection | ||
513 | Intel(R) PRO/1000 PT Dual Port Server Connection | ||
514 | Intel(R) PRO/1000 PT Dual Port Server Adapter | ||
515 | Intel(R) PRO/1000 PF Dual Port Server Adapter | ||
516 | Intel(R) PRO/1000 PT Quad Port Server Adapter | ||
517 | |||
518 | NAPI | ||
519 | ---- | ||
520 | NAPI (Rx polling mode) is enabled in the e1000 driver. | ||
521 | |||
522 | See www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI. | ||
523 | |||
524 | |||
525 | Known Issues | ||
526 | ============ | ||
527 | |||
528 | Dropped Receive Packets on Half-duplex 10/100 Networks | ||
529 | ------------------------------------------------------ | ||
530 | If you have an Intel PCI Express adapter running at 10mbps or 100mbps, half- | ||
531 | duplex, you may observe occasional dropped receive packets. There are no | ||
532 | workarounds for this problem in this network configuration. The network must | ||
533 | be updated to operate in full-duplex, and/or 1000mbps only. | ||
534 | |||
535 | Jumbo Frames System Requirement | ||
536 | ------------------------------- | ||
537 | Memory allocation failures have been observed on Linux systems with 64 MB | ||
538 | of RAM or less that are running Jumbo Frames. If you are using Jumbo | ||
539 | Frames, your system may require more than the advertised minimum | ||
540 | requirement of 64 MB of system memory. | ||
541 | |||
542 | Performance Degradation with Jumbo Frames | ||
543 | ----------------------------------------- | ||
544 | Degradation in throughput performance may be observed in some Jumbo frames | ||
545 | environments. If this is observed, increasing the application's socket | ||
546 | buffer size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values | ||
547 | may help. See the specific application manual and | ||
548 | /usr/src/linux*/Documentation/ | ||
549 | networking/ip-sysctl.txt for more details. | ||
550 | |||
551 | Jumbo Frames on Foundry BigIron 8000 switch | ||
552 | ------------------------------------------- | ||
553 | There is a known issue using Jumbo frames when connected to a Foundry | ||
554 | BigIron 8000 switch. This is a 3rd party limitation. If you experience | ||
555 | loss of packets, lower the MTU size. | ||
556 | |||
557 | Allocating Rx Buffers when Using Jumbo Frames | ||
558 | --------------------------------------------- | ||
559 | Allocating Rx buffers when using Jumbo Frames on 2.6.x kernels may fail if | ||
560 | the available memory is heavily fragmented. This issue may be seen with PCI-X | ||
561 | adapters or with packet split disabled. This can be reduced or eliminated | ||
562 | by changing the amount of available memory for receive buffer allocation, by | ||
563 | increasing /proc/sys/vm/min_free_kbytes. | ||
564 | |||
565 | Multiple Interfaces on Same Ethernet Broadcast Network | ||
566 | ------------------------------------------------------ | ||
567 | Due to the default ARP behavior on Linux, it is not possible to have | ||
568 | one system on two IP networks in the same Ethernet broadcast domain | ||
569 | (non-partitioned switch) behave as expected. All Ethernet interfaces | ||
570 | will respond to IP traffic for any IP address assigned to the system. | ||
571 | This results in unbalanced receive traffic. | ||
572 | |||
573 | If you have multiple interfaces in a server, either turn on ARP | ||
574 | filtering by entering: | ||
575 | |||
576 | echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter | ||
577 | (this only works if your kernel's version is higher than 2.4.5), | ||
578 | |||
579 | NOTE: This setting is not saved across reboots. The configuration | ||
580 | change can be made permanent by adding the line: | ||
581 | net.ipv4.conf.all.arp_filter = 1 | ||
582 | to the file /etc/sysctl.conf | ||
583 | |||
584 | or, | ||
585 | |||
586 | install the interfaces in separate broadcast domains (either in | ||
587 | different switches or in a switch partitioned to VLANs). | ||
588 | |||
589 | 82541/82547 can't link or are slow to link with some link partners | ||
590 | ----------------------------------------------------------------- | ||
591 | There is a known compatibility issue with 82541/82547 and some | ||
592 | low-end switches where the link will not be established, or will | ||
593 | be slow to establish. In particular, these switches are known to | ||
594 | be incompatible with 82541/82547: | ||
595 | |||
596 | Planex FXG-08TE | ||
597 | I-O Data ETG-SH8 | ||
598 | |||
599 | To workaround this issue, the driver can be compiled with an override | ||
600 | of the PHY's master/slave setting. Forcing master or forcing slave | ||
601 | mode will improve time-to-link. | ||
602 | |||
603 | # make CFLAGS_EXTRA=-DE1000_MASTER_SLAVE=<n> | ||
604 | |||
605 | Where <n> is: | ||
606 | |||
607 | 0 = Hardware default | ||
608 | 1 = Master mode | ||
609 | 2 = Slave mode | ||
610 | 3 = Auto master/slave | ||
611 | |||
612 | Disable rx flow control with ethtool | ||
613 | ------------------------------------ | ||
614 | In order to disable receive flow control using ethtool, you must turn | ||
615 | off auto-negotiation on the same command line. | ||
616 | |||
617 | For example: | ||
618 | |||
619 | ethtool -A eth? autoneg off rx off | ||
620 | |||
621 | Unplugging network cable while ethtool -p is running | ||
622 | ---------------------------------------------------- | ||
623 | In kernel versions 2.5.50 and later (including 2.6 kernel), unplugging | ||
624 | the network cable while ethtool -p is running will cause the system to | ||
625 | become unresponsive to keyboard commands, except for control-alt-delete. | ||
626 | Restarting the system appears to be the only remedy. | ||
627 | |||
628 | |||
629 | Support | 448 | Support |
630 | ======= | 449 | ======= |
631 | 450 | ||
diff --git a/Documentation/networking/e1000e.txt b/Documentation/networking/e1000e.txt new file mode 100644 index 00000000000..6aa048badf3 --- /dev/null +++ b/Documentation/networking/e1000e.txt | |||
@@ -0,0 +1,302 @@ | |||
1 | Linux* Driver for Intel(R) Network Connection | ||
2 | =============================================================== | ||
3 | |||
4 | Intel Gigabit Linux driver. | ||
5 | Copyright(c) 1999 - 2010 Intel Corporation. | ||
6 | |||
7 | Contents | ||
8 | ======== | ||
9 | |||
10 | - Identifying Your Adapter | ||
11 | - Command Line Parameters | ||
12 | - Additional Configurations | ||
13 | - Support | ||
14 | |||
15 | Identifying Your Adapter | ||
16 | ======================== | ||
17 | |||
18 | The e1000e driver supports all PCI Express Intel(R) Gigabit Network | ||
19 | Connections, except those that are 82575, 82576 and 82580-based*. | ||
20 | |||
21 | * NOTE: The Intel(R) PRO/1000 P Dual Port Server Adapter is supported by | ||
22 | the e1000 driver, not the e1000e driver due to the 82546 part being used | ||
23 | behind a PCI Express bridge. | ||
24 | |||
25 | For more information on how to identify your adapter, go to the Adapter & | ||
26 | Driver ID Guide at: | ||
27 | |||
28 | http://support.intel.com/support/go/network/adapter/idguide.htm | ||
29 | |||
30 | For the latest Intel network drivers for Linux, refer to the following | ||
31 | website. In the search field, enter your adapter name or type, or use the | ||
32 | networking link on the left to search for your adapter: | ||
33 | |||
34 | http://support.intel.com/support/go/network/adapter/home.htm | ||
35 | |||
36 | Command Line Parameters | ||
37 | ======================= | ||
38 | |||
39 | The default value for each parameter is generally the recommended setting, | ||
40 | unless otherwise noted. | ||
41 | |||
42 | NOTES: For more information about the InterruptThrottleRate, | ||
43 | RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay | ||
44 | parameters, see the application note at: | ||
45 | http://www.intel.com/design/network/applnots/ap450.htm | ||
46 | |||
47 | InterruptThrottleRate | ||
48 | --------------------- | ||
49 | Valid Range: 0,1,3,4,100-100000 (0=off, 1=dynamic, 3=dynamic conservative, | ||
50 | 4=simplified balancing) | ||
51 | Default Value: 3 | ||
52 | |||
53 | The driver can limit the amount of interrupts per second that the adapter | ||
54 | will generate for incoming packets. It does this by writing a value to the | ||
55 | adapter that is based on the maximum amount of interrupts that the adapter | ||
56 | will generate per second. | ||
57 | |||
58 | Setting InterruptThrottleRate to a value greater or equal to 100 | ||
59 | will program the adapter to send out a maximum of that many interrupts | ||
60 | per second, even if more packets have come in. This reduces interrupt | ||
61 | load on the system and can lower CPU utilization under heavy load, | ||
62 | but will increase latency as packets are not processed as quickly. | ||
63 | |||
64 | The driver has two adaptive modes (setting 1 or 3) in which | ||
65 | it dynamically adjusts the InterruptThrottleRate value based on the traffic | ||
66 | that it receives. After determining the type of incoming traffic in the last | ||
67 | timeframe, it will adjust the InterruptThrottleRate to an appropriate value | ||
68 | for that traffic. | ||
69 | |||
70 | The algorithm classifies the incoming traffic every interval into | ||
71 | classes. Once the class is determined, the InterruptThrottleRate value is | ||
72 | adjusted to suit that traffic type the best. There are three classes defined: | ||
73 | "Bulk traffic", for large amounts of packets of normal size; "Low latency", | ||
74 | for small amounts of traffic and/or a significant percentage of small | ||
75 | packets; and "Lowest latency", for almost completely small packets or | ||
76 | minimal traffic. | ||
77 | |||
78 | In dynamic conservative mode, the InterruptThrottleRate value is set to 4000 | ||
79 | for traffic that falls in class "Bulk traffic". If traffic falls in the "Low | ||
80 | latency" or "Lowest latency" class, the InterruptThrottleRate is increased | ||
81 | stepwise to 20000. This default mode is suitable for most applications. | ||
82 | |||
83 | For situations where low latency is vital such as cluster or | ||
84 | grid computing, the algorithm can reduce latency even more when | ||
85 | InterruptThrottleRate is set to mode 1. In this mode, which operates | ||
86 | the same as mode 3, the InterruptThrottleRate will be increased stepwise to | ||
87 | 70000 for traffic in class "Lowest latency". | ||
88 | |||
89 | In simplified mode the interrupt rate is based on the ratio of Tx and | ||
90 | Rx traffic. If the bytes per second rate is approximately equal the | ||
91 | interrupt rate will drop as low as 2000 interrupts per second. If the | ||
92 | traffic is mostly transmit or mostly receive, the interrupt rate could | ||
93 | be as high as 8000. | ||
94 | |||
95 | Setting InterruptThrottleRate to 0 turns off any interrupt moderation | ||
96 | and may improve small packet latency, but is generally not suitable | ||
97 | for bulk throughput traffic. | ||
98 | |||
99 | NOTE: InterruptThrottleRate takes precedence over the TxAbsIntDelay and | ||
100 | RxAbsIntDelay parameters. In other words, minimizing the receive | ||
101 | and/or transmit absolute delays does not force the controller to | ||
102 | generate more interrupts than what the Interrupt Throttle Rate | ||
103 | allows. | ||
104 | |||
105 | NOTE: When e1000e is loaded with default settings and multiple adapters | ||
106 | are in use simultaneously, the CPU utilization may increase non- | ||
107 | linearly. In order to limit the CPU utilization without impacting | ||
108 | the overall throughput, we recommend that you load the driver as | ||
109 | follows: | ||
110 | |||
111 | modprobe e1000e InterruptThrottleRate=3000,3000,3000 | ||
112 | |||
113 | This sets the InterruptThrottleRate to 3000 interrupts/sec for | ||
114 | the first, second, and third instances of the driver. The range | ||
115 | of 2000 to 3000 interrupts per second works on a majority of | ||
116 | systems and is a good starting point, but the optimal value will | ||
117 | be platform-specific. If CPU utilization is not a concern, use | ||
118 | RX_POLLING (NAPI) and default driver settings. | ||
119 | |||
120 | RxIntDelay | ||
121 | ---------- | ||
122 | Valid Range: 0-65535 (0=off) | ||
123 | Default Value: 0 | ||
124 | |||
125 | This value delays the generation of receive interrupts in units of 1.024 | ||
126 | microseconds. Receive interrupt reduction can improve CPU efficiency if | ||
127 | properly tuned for specific network traffic. Increasing this value adds | ||
128 | extra latency to frame reception and can end up decreasing the throughput | ||
129 | of TCP traffic. If the system is reporting dropped receives, this value | ||
130 | may be set too high, causing the driver to run out of available receive | ||
131 | descriptors. | ||
132 | |||
133 | CAUTION: When setting RxIntDelay to a value other than 0, adapters may | ||
134 | hang (stop transmitting) under certain network conditions. If | ||
135 | this occurs a NETDEV WATCHDOG message is logged in the system | ||
136 | event log. In addition, the controller is automatically reset, | ||
137 | restoring the network connection. To eliminate the potential | ||
138 | for the hang ensure that RxIntDelay is set to 0. | ||
139 | |||
140 | RxAbsIntDelay | ||
141 | ------------- | ||
142 | Valid Range: 0-65535 (0=off) | ||
143 | Default Value: 8 | ||
144 | |||
145 | This value, in units of 1.024 microseconds, limits the delay in which a | ||
146 | receive interrupt is generated. Useful only if RxIntDelay is non-zero, | ||
147 | this value ensures that an interrupt is generated after the initial | ||
148 | packet is received within the set amount of time. Proper tuning, | ||
149 | along with RxIntDelay, may improve traffic throughput in specific network | ||
150 | conditions. | ||
151 | |||
152 | TxIntDelay | ||
153 | ---------- | ||
154 | Valid Range: 0-65535 (0=off) | ||
155 | Default Value: 8 | ||
156 | |||
157 | This value delays the generation of transmit interrupts in units of | ||
158 | 1.024 microseconds. Transmit interrupt reduction can improve CPU | ||
159 | efficiency if properly tuned for specific network traffic. If the | ||
160 | system is reporting dropped transmits, this value may be set too high | ||
161 | causing the driver to run out of available transmit descriptors. | ||
162 | |||
163 | TxAbsIntDelay | ||
164 | ------------- | ||
165 | Valid Range: 0-65535 (0=off) | ||
166 | Default Value: 32 | ||
167 | |||
168 | This value, in units of 1.024 microseconds, limits the delay in which a | ||
169 | transmit interrupt is generated. Useful only if TxIntDelay is non-zero, | ||
170 | this value ensures that an interrupt is generated after the initial | ||
171 | packet is sent on the wire within the set amount of time. Proper tuning, | ||
172 | along with TxIntDelay, may improve traffic throughput in specific | ||
173 | network conditions. | ||
174 | |||
175 | Copybreak | ||
176 | --------- | ||
177 | Valid Range: 0-xxxxxxx (0=off) | ||
178 | Default Value: 256 | ||
179 | |||
180 | Driver copies all packets below or equaling this size to a fresh Rx | ||
181 | buffer before handing it up the stack. | ||
182 | |||
183 | This parameter is different than other parameters, in that it is a | ||
184 | single (not 1,1,1 etc.) parameter applied to all driver instances and | ||
185 | it is also available during runtime at | ||
186 | /sys/module/e1000e/parameters/copybreak | ||
187 | |||
188 | SmartPowerDownEnable | ||
189 | -------------------- | ||
190 | Valid Range: 0-1 | ||
191 | Default Value: 0 (disabled) | ||
192 | |||
193 | Allows PHY to turn off in lower power states. The user can set this parameter | ||
194 | in supported chipsets. | ||
195 | |||
196 | KumeranLockLoss | ||
197 | --------------- | ||
198 | Valid Range: 0-1 | ||
199 | Default Value: 1 (enabled) | ||
200 | |||
201 | This workaround skips resetting the PHY at shutdown for the initial | ||
202 | silicon releases of ICH8 systems. | ||
203 | |||
204 | IntMode | ||
205 | ------- | ||
206 | Valid Range: 0-2 (0=legacy, 1=MSI, 2=MSI-X) | ||
207 | Default Value: 2 | ||
208 | |||
209 | Allows changing the interrupt mode at module load time, without requiring a | ||
210 | recompile. If the driver load fails to enable a specific interrupt mode, the | ||
211 | driver will try other interrupt modes, from least to most compatible. The | ||
212 | interrupt order is MSI-X, MSI, Legacy. If specifying MSI (IntMode=1) | ||
213 | interrupts, only MSI and Legacy will be attempted. | ||
214 | |||
215 | CrcStripping | ||
216 | ------------ | ||
217 | Valid Range: 0-1 | ||
218 | Default Value: 1 (enabled) | ||
219 | |||
220 | Strip the CRC from received packets before sending up the network stack. If | ||
221 | you have a machine with a BMC enabled but cannot receive IPMI traffic after | ||
222 | loading or enabling the driver, try disabling this feature. | ||
223 | |||
224 | WriteProtectNVM | ||
225 | --------------- | ||
226 | Valid Range: 0-1 | ||
227 | Default Value: 1 (enabled) | ||
228 | |||
229 | Set the hardware to ignore all write/erase cycles to the GbE region in the | ||
230 | ICHx NVM (non-volatile memory). This feature can be disabled by the | ||
231 | WriteProtectNVM module parameter (enabled by default) only after a hardware | ||
232 | reset, but the machine must be power cycled before trying to enable writes. | ||
233 | |||
234 | Note: the kernel boot option iomem=relaxed may need to be set if the kernel | ||
235 | config option CONFIG_STRICT_DEVMEM=y, if the root user wants to write the | ||
236 | NVM from user space via ethtool. | ||
237 | |||
238 | Additional Configurations | ||
239 | ========================= | ||
240 | |||
241 | Jumbo Frames | ||
242 | ------------ | ||
243 | Jumbo Frames support is enabled by changing the MTU to a value larger than | ||
244 | the default of 1500. Use the ifconfig command to increase the MTU size. | ||
245 | For example: | ||
246 | |||
247 | ifconfig eth<x> mtu 9000 up | ||
248 | |||
249 | This setting is not saved across reboots. | ||
250 | |||
251 | Notes: | ||
252 | |||
253 | - The maximum MTU setting for Jumbo Frames is 9216. This value coincides | ||
254 | with the maximum Jumbo Frames size of 9234 bytes. | ||
255 | |||
256 | - Using Jumbo Frames at 10 or 100 Mbps is not supported and may result in | ||
257 | poor performance or loss of link. | ||
258 | |||
259 | - Some adapters limit Jumbo Frames sized packets to a maximum of | ||
260 | 4096 bytes and some adapters do not support Jumbo Frames. | ||
261 | |||
262 | |||
263 | Ethtool | ||
264 | ------- | ||
265 | The driver utilizes the ethtool interface for driver configuration and | ||
266 | diagnostics, as well as displaying statistical information. We | ||
267 | strongly recommend downloading the latest version of Ethtool at: | ||
268 | |||
269 | http://sourceforge.net/projects/gkernel. | ||
270 | |||
271 | Speed and Duplex | ||
272 | ---------------- | ||
273 | Speed and Duplex are configured through the Ethtool* utility. For | ||
274 | instructions, refer to the Ethtool man page. | ||
275 | |||
276 | Enabling Wake on LAN* (WoL) | ||
277 | --------------------------- | ||
278 | WoL is configured through the Ethtool* utility. For instructions on | ||
279 | enabling WoL with Ethtool, refer to the Ethtool man page. | ||
280 | |||
281 | WoL will be enabled on the system during the next shut down or reboot. | ||
282 | For this driver version, in order to enable WoL, the e1000e driver must be | ||
283 | loaded when shutting down or rebooting the system. | ||
284 | |||
285 | In most cases Wake On LAN is only supported on port A for multiple port | ||
286 | adapters. To verify if a port supports Wake on LAN run ethtool eth<X>. | ||
287 | |||
288 | |||
289 | Support | ||
290 | ======= | ||
291 | |||
292 | For general information, go to the Intel support website at: | ||
293 | |||
294 | www.intel.com/support/ | ||
295 | |||
296 | or the Intel Wired Networking project hosted by Sourceforge at: | ||
297 | |||
298 | http://sourceforge.net/projects/e1000 | ||
299 | |||
300 | If an issue is identified with the released source code on the supported | ||
301 | kernel with a supported adapter, email the specific information related | ||
302 | to the issue to e1000-devel@lists.sf.net | ||
diff --git a/Documentation/networking/ixgbevf.txt b/Documentation/networking/ixgbevf.txt index 19015de6725..21dd5d15b6b 100755..100644 --- a/Documentation/networking/ixgbevf.txt +++ b/Documentation/networking/ixgbevf.txt | |||
@@ -1,19 +1,16 @@ | |||
1 | Linux* Base Driver for Intel(R) Network Connection | 1 | Linux* Base Driver for Intel(R) Network Connection |
2 | ================================================== | 2 | ================================================== |
3 | 3 | ||
4 | November 24, 2009 | 4 | Intel Gigabit Linux driver. |
5 | Copyright(c) 1999 - 2010 Intel Corporation. | ||
5 | 6 | ||
6 | Contents | 7 | Contents |
7 | ======== | 8 | ======== |
8 | 9 | ||
9 | - In This Release | ||
10 | - Identifying Your Adapter | 10 | - Identifying Your Adapter |
11 | - Known Issues/Troubleshooting | 11 | - Known Issues/Troubleshooting |
12 | - Support | 12 | - Support |
13 | 13 | ||
14 | In This Release | ||
15 | =============== | ||
16 | |||
17 | This file describes the ixgbevf Linux* Base Driver for Intel Network | 14 | This file describes the ixgbevf Linux* Base Driver for Intel Network |
18 | Connection. | 15 | Connection. |
19 | 16 | ||
@@ -33,7 +30,7 @@ Identifying Your Adapter | |||
33 | For more information on how to identify your adapter, go to the Adapter & | 30 | For more information on how to identify your adapter, go to the Adapter & |
34 | Driver ID Guide at: | 31 | Driver ID Guide at: |
35 | 32 | ||
36 | http://support.intel.com/support/network/sb/CS-008441.htm | 33 | http://support.intel.com/support/go/network/adapter/idguide.htm |
37 | 34 | ||
38 | Known Issues/Troubleshooting | 35 | Known Issues/Troubleshooting |
39 | ============================ | 36 | ============================ |
@@ -57,34 +54,3 @@ or the Intel Wired Networking project hosted by Sourceforge at: | |||
57 | If an issue is identified with the released source code on the supported | 54 | If an issue is identified with the released source code on the supported |
58 | kernel with a supported adapter, email the specific information related | 55 | kernel with a supported adapter, email the specific information related |
59 | to the issue to e1000-devel@lists.sf.net | 56 | to the issue to e1000-devel@lists.sf.net |
60 | |||
61 | License | ||
62 | ======= | ||
63 | |||
64 | Intel 10 Gigabit Linux driver. | ||
65 | Copyright(c) 1999 - 2009 Intel Corporation. | ||
66 | |||
67 | This program is free software; you can redistribute it and/or modify it | ||
68 | under the terms and conditions of the GNU General Public License, | ||
69 | version 2, as published by the Free Software Foundation. | ||
70 | |||
71 | This program is distributed in the hope it will be useful, but WITHOUT | ||
72 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
73 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | ||
74 | more details. | ||
75 | |||
76 | You should have received a copy of the GNU General Public License along with | ||
77 | this program; if not, write to the Free Software Foundation, Inc., | ||
78 | 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | ||
79 | |||
80 | The full GNU General Public License is included in this distribution in | ||
81 | the file called "COPYING". | ||
82 | |||
83 | Trademarks | ||
84 | ========== | ||
85 | |||
86 | Intel, Itanium, and Pentium are trademarks or registered trademarks of | ||
87 | Intel Corporation or its subsidiaries in the United States and other | ||
88 | countries. | ||
89 | |||
90 | * Other names and brands may be claimed as the property of others. | ||
diff --git a/Documentation/pcmcia/driver-changes.txt b/Documentation/pcmcia/driver-changes.txt index 26c0f9c0054..dd04361dd36 100644 --- a/Documentation/pcmcia/driver-changes.txt +++ b/Documentation/pcmcia/driver-changes.txt | |||
@@ -1,4 +1,29 @@ | |||
1 | This file details changes in 2.6 which affect PCMCIA card driver authors: | 1 | This file details changes in 2.6 which affect PCMCIA card driver authors: |
2 | * pcmcia_loop_config() and autoconfiguration (as of 2.6.36) | ||
3 | If struct pcmcia_device *p_dev->config_flags is set accordingly, | ||
4 | pcmcia_loop_config() now sets up certain configuration values | ||
5 | automatically, though the driver may still override the settings | ||
6 | in the callback function. The following autoconfiguration options | ||
7 | are provided at the moment: | ||
8 | CONF_AUTO_CHECK_VCC : check for matching Vcc | ||
9 | CONF_AUTO_SET_VPP : set Vpp | ||
10 | CONF_AUTO_AUDIO : auto-enable audio line, if required | ||
11 | CONF_AUTO_SET_IO : set ioport resources (->resource[0,1]) | ||
12 | CONF_AUTO_SET_IOMEM : set first iomem resource (->resource[2]) | ||
13 | |||
14 | * pcmcia_request_configuration -> pcmcia_enable_device (as of 2.6.36) | ||
15 | pcmcia_request_configuration() got renamed to pcmcia_enable_device(), | ||
16 | as it mirrors pcmcia_disable_device(). Configuration settings are now | ||
17 | stored in struct pcmcia_device, e.g. in the fields config_flags, | ||
18 | config_index, config_base, vpp. | ||
19 | |||
20 | * pcmcia_request_window changes (as of 2.6.36) | ||
21 | Instead of win_req_t, drivers are now requested to fill out | ||
22 | struct pcmcia_device *p_dev->resource[2,3,4,5] for up to four ioport | ||
23 | ranges. After a call to pcmcia_request_window(), the regions found there | ||
24 | are reserved and may be used immediately -- until pcmcia_release_window() | ||
25 | is called. | ||
26 | |||
2 | * pcmcia_request_io changes (as of 2.6.36) | 27 | * pcmcia_request_io changes (as of 2.6.36) |
3 | Instead of io_req_t, drivers are now requested to fill out | 28 | Instead of io_req_t, drivers are now requested to fill out |
4 | struct pcmcia_device *p_dev->resource[0,1] for up to two ioport | 29 | struct pcmcia_device *p_dev->resource[0,1] for up to two ioport |
diff --git a/Documentation/power/00-INDEX b/Documentation/power/00-INDEX index fb742c213c9..45e9d4a9128 100644 --- a/Documentation/power/00-INDEX +++ b/Documentation/power/00-INDEX | |||
@@ -14,6 +14,8 @@ interface.txt | |||
14 | - Power management user interface in /sys/power | 14 | - Power management user interface in /sys/power |
15 | notifiers.txt | 15 | notifiers.txt |
16 | - Registering suspend notifiers in device drivers | 16 | - Registering suspend notifiers in device drivers |
17 | opp.txt | ||
18 | - Operating Performance Point library | ||
17 | pci.txt | 19 | pci.txt |
18 | - How the PCI Subsystem Does Power Management | 20 | - How the PCI Subsystem Does Power Management |
19 | pm_qos_interface.txt | 21 | pm_qos_interface.txt |
diff --git a/Documentation/power/interface.txt b/Documentation/power/interface.txt index e67211fe0ee..c537834af00 100644 --- a/Documentation/power/interface.txt +++ b/Documentation/power/interface.txt | |||
@@ -57,7 +57,7 @@ smallest image possible. In particular, if "0" is written to this file, the | |||
57 | suspend image will be as small as possible. | 57 | suspend image will be as small as possible. |
58 | 58 | ||
59 | Reading from this file will display the current image size limit, which | 59 | Reading from this file will display the current image size limit, which |
60 | is set to 500 MB by default. | 60 | is set to 2/5 of available RAM by default. |
61 | 61 | ||
62 | /sys/power/pm_trace controls the code which saves the last PM event point in | 62 | /sys/power/pm_trace controls the code which saves the last PM event point in |
63 | the RTC across reboots, so that you can debug a machine that just hangs | 63 | the RTC across reboots, so that you can debug a machine that just hangs |
diff --git a/Documentation/power/opp.txt b/Documentation/power/opp.txt new file mode 100644 index 00000000000..44d87ad3cea --- /dev/null +++ b/Documentation/power/opp.txt | |||
@@ -0,0 +1,375 @@ | |||
1 | *=============* | ||
2 | * OPP Library * | ||
3 | *=============* | ||
4 | |||
5 | (C) 2009-2010 Nishanth Menon <nm@ti.com>, Texas Instruments Incorporated | ||
6 | |||
7 | Contents | ||
8 | -------- | ||
9 | 1. Introduction | ||
10 | 2. Initial OPP List Registration | ||
11 | 3. OPP Search Functions | ||
12 | 4. OPP Availability Control Functions | ||
13 | 5. OPP Data Retrieval Functions | ||
14 | 6. Cpufreq Table Generation | ||
15 | 7. Data Structures | ||
16 | |||
17 | 1. Introduction | ||
18 | =============== | ||
19 | Complex SoCs of today consists of a multiple sub-modules working in conjunction. | ||
20 | In an operational system executing varied use cases, not all modules in the SoC | ||
21 | need to function at their highest performing frequency all the time. To | ||
22 | facilitate this, sub-modules in a SoC are grouped into domains, allowing some | ||
23 | domains to run at lower voltage and frequency while other domains are loaded | ||
24 | more. The set of discrete tuples consisting of frequency and voltage pairs that | ||
25 | the device will support per domain are called Operating Performance Points or | ||
26 | OPPs. | ||
27 | |||
28 | OPP library provides a set of helper functions to organize and query the OPP | ||
29 | information. The library is located in drivers/base/power/opp.c and the header | ||
30 | is located in include/linux/opp.h. OPP library can be enabled by enabling | ||
31 | CONFIG_PM_OPP from power management menuconfig menu. OPP library depends on | ||
32 | CONFIG_PM as certain SoCs such as Texas Instrument's OMAP framework allows to | ||
33 | optionally boot at a certain OPP without needing cpufreq. | ||
34 | |||
35 | Typical usage of the OPP library is as follows: | ||
36 | (users) -> registers a set of default OPPs -> (library) | ||
37 | SoC framework -> modifies on required cases certain OPPs -> OPP layer | ||
38 | -> queries to search/retrieve information -> | ||
39 | |||
40 | OPP layer expects each domain to be represented by a unique device pointer. SoC | ||
41 | framework registers a set of initial OPPs per device with the OPP layer. This | ||
42 | list is expected to be an optimally small number typically around 5 per device. | ||
43 | This initial list contains a set of OPPs that the framework expects to be safely | ||
44 | enabled by default in the system. | ||
45 | |||
46 | Note on OPP Availability: | ||
47 | ------------------------ | ||
48 | As the system proceeds to operate, SoC framework may choose to make certain | ||
49 | OPPs available or not available on each device based on various external | ||
50 | factors. Example usage: Thermal management or other exceptional situations where | ||
51 | SoC framework might choose to disable a higher frequency OPP to safely continue | ||
52 | operations until that OPP could be re-enabled if possible. | ||
53 | |||
54 | OPP library facilitates this concept in it's implementation. The following | ||
55 | operational functions operate only on available opps: | ||
56 | opp_find_freq_{ceil, floor}, opp_get_voltage, opp_get_freq, opp_get_opp_count | ||
57 | and opp_init_cpufreq_table | ||
58 | |||
59 | opp_find_freq_exact is meant to be used to find the opp pointer which can then | ||
60 | be used for opp_enable/disable functions to make an opp available as required. | ||
61 | |||
62 | WARNING: Users of OPP library should refresh their availability count using | ||
63 | get_opp_count if opp_enable/disable functions are invoked for a device, the | ||
64 | exact mechanism to trigger these or the notification mechanism to other | ||
65 | dependent subsystems such as cpufreq are left to the discretion of the SoC | ||
66 | specific framework which uses the OPP library. Similar care needs to be taken | ||
67 | care to refresh the cpufreq table in cases of these operations. | ||
68 | |||
69 | WARNING on OPP List locking mechanism: | ||
70 | ------------------------------------------------- | ||
71 | OPP library uses RCU for exclusivity. RCU allows the query functions to operate | ||
72 | in multiple contexts and this synchronization mechanism is optimal for a read | ||
73 | intensive operations on data structure as the OPP library caters to. | ||
74 | |||
75 | To ensure that the data retrieved are sane, the users such as SoC framework | ||
76 | should ensure that the section of code operating on OPP queries are locked | ||
77 | using RCU read locks. The opp_find_freq_{exact,ceil,floor}, | ||
78 | opp_get_{voltage, freq, opp_count} fall into this category. | ||
79 | |||
80 | opp_{add,enable,disable} are updaters which use mutex and implement it's own | ||
81 | RCU locking mechanisms. opp_init_cpufreq_table acts as an updater and uses | ||
82 | mutex to implment RCU updater strategy. These functions should *NOT* be called | ||
83 | under RCU locks and other contexts that prevent blocking functions in RCU or | ||
84 | mutex operations from working. | ||
85 | |||
86 | 2. Initial OPP List Registration | ||
87 | ================================ | ||
88 | The SoC implementation calls opp_add function iteratively to add OPPs per | ||
89 | device. It is expected that the SoC framework will register the OPP entries | ||
90 | optimally- typical numbers range to be less than 5. The list generated by | ||
91 | registering the OPPs is maintained by OPP library throughout the device | ||
92 | operation. The SoC framework can subsequently control the availability of the | ||
93 | OPPs dynamically using the opp_enable / disable functions. | ||
94 | |||
95 | opp_add - Add a new OPP for a specific domain represented by the device pointer. | ||
96 | The OPP is defined using the frequency and voltage. Once added, the OPP | ||
97 | is assumed to be available and control of it's availability can be done | ||
98 | with the opp_enable/disable functions. OPP library internally stores | ||
99 | and manages this information in the opp struct. This function may be | ||
100 | used by SoC framework to define a optimal list as per the demands of | ||
101 | SoC usage environment. | ||
102 | |||
103 | WARNING: Do not use this function in interrupt context. | ||
104 | |||
105 | Example: | ||
106 | soc_pm_init() | ||
107 | { | ||
108 | /* Do things */ | ||
109 | r = opp_add(mpu_dev, 1000000, 900000); | ||
110 | if (!r) { | ||
111 | pr_err("%s: unable to register mpu opp(%d)\n", r); | ||
112 | goto no_cpufreq; | ||
113 | } | ||
114 | /* Do cpufreq things */ | ||
115 | no_cpufreq: | ||
116 | /* Do remaining things */ | ||
117 | } | ||
118 | |||
119 | 3. OPP Search Functions | ||
120 | ======================= | ||
121 | High level framework such as cpufreq operates on frequencies. To map the | ||
122 | frequency back to the corresponding OPP, OPP library provides handy functions | ||
123 | to search the OPP list that OPP library internally manages. These search | ||
124 | functions return the matching pointer representing the opp if a match is | ||
125 | found, else returns error. These errors are expected to be handled by standard | ||
126 | error checks such as IS_ERR() and appropriate actions taken by the caller. | ||
127 | |||
128 | opp_find_freq_exact - Search for an OPP based on an *exact* frequency and | ||
129 | availability. This function is especially useful to enable an OPP which | ||
130 | is not available by default. | ||
131 | Example: In a case when SoC framework detects a situation where a | ||
132 | higher frequency could be made available, it can use this function to | ||
133 | find the OPP prior to call the opp_enable to actually make it available. | ||
134 | rcu_read_lock(); | ||
135 | opp = opp_find_freq_exact(dev, 1000000000, false); | ||
136 | rcu_read_unlock(); | ||
137 | /* dont operate on the pointer.. just do a sanity check.. */ | ||
138 | if (IS_ERR(opp)) { | ||
139 | pr_err("frequency not disabled!\n"); | ||
140 | /* trigger appropriate actions.. */ | ||
141 | } else { | ||
142 | opp_enable(dev,1000000000); | ||
143 | } | ||
144 | |||
145 | NOTE: This is the only search function that operates on OPPs which are | ||
146 | not available. | ||
147 | |||
148 | opp_find_freq_floor - Search for an available OPP which is *at most* the | ||
149 | provided frequency. This function is useful while searching for a lesser | ||
150 | match OR operating on OPP information in the order of decreasing | ||
151 | frequency. | ||
152 | Example: To find the highest opp for a device: | ||
153 | freq = ULONG_MAX; | ||
154 | rcu_read_lock(); | ||
155 | opp_find_freq_floor(dev, &freq); | ||
156 | rcu_read_unlock(); | ||
157 | |||
158 | opp_find_freq_ceil - Search for an available OPP which is *at least* the | ||
159 | provided frequency. This function is useful while searching for a | ||
160 | higher match OR operating on OPP information in the order of increasing | ||
161 | frequency. | ||
162 | Example 1: To find the lowest opp for a device: | ||
163 | freq = 0; | ||
164 | rcu_read_lock(); | ||
165 | opp_find_freq_ceil(dev, &freq); | ||
166 | rcu_read_unlock(); | ||
167 | Example 2: A simplified implementation of a SoC cpufreq_driver->target: | ||
168 | soc_cpufreq_target(..) | ||
169 | { | ||
170 | /* Do stuff like policy checks etc. */ | ||
171 | /* Find the best frequency match for the req */ | ||
172 | rcu_read_lock(); | ||
173 | opp = opp_find_freq_ceil(dev, &freq); | ||
174 | rcu_read_unlock(); | ||
175 | if (!IS_ERR(opp)) | ||
176 | soc_switch_to_freq_voltage(freq); | ||
177 | else | ||
178 | /* do something when we cant satisfy the req */ | ||
179 | /* do other stuff */ | ||
180 | } | ||
181 | |||
182 | 4. OPP Availability Control Functions | ||
183 | ===================================== | ||
184 | A default OPP list registered with the OPP library may not cater to all possible | ||
185 | situation. The OPP library provides a set of functions to modify the | ||
186 | availability of a OPP within the OPP list. This allows SoC frameworks to have | ||
187 | fine grained dynamic control of which sets of OPPs are operationally available. | ||
188 | These functions are intended to *temporarily* remove an OPP in conditions such | ||
189 | as thermal considerations (e.g. don't use OPPx until the temperature drops). | ||
190 | |||
191 | WARNING: Do not use these functions in interrupt context. | ||
192 | |||
193 | opp_enable - Make a OPP available for operation. | ||
194 | Example: Lets say that 1GHz OPP is to be made available only if the | ||
195 | SoC temperature is lower than a certain threshold. The SoC framework | ||
196 | implementation might choose to do something as follows: | ||
197 | if (cur_temp < temp_low_thresh) { | ||
198 | /* Enable 1GHz if it was disabled */ | ||
199 | rcu_read_lock(); | ||
200 | opp = opp_find_freq_exact(dev, 1000000000, false); | ||
201 | rcu_read_unlock(); | ||
202 | /* just error check */ | ||
203 | if (!IS_ERR(opp)) | ||
204 | ret = opp_enable(dev, 1000000000); | ||
205 | else | ||
206 | goto try_something_else; | ||
207 | } | ||
208 | |||
209 | opp_disable - Make an OPP to be not available for operation | ||
210 | Example: Lets say that 1GHz OPP is to be disabled if the temperature | ||
211 | exceeds a threshold value. The SoC framework implementation might | ||
212 | choose to do something as follows: | ||
213 | if (cur_temp > temp_high_thresh) { | ||
214 | /* Disable 1GHz if it was enabled */ | ||
215 | rcu_read_lock(); | ||
216 | opp = opp_find_freq_exact(dev, 1000000000, true); | ||
217 | rcu_read_unlock(); | ||
218 | /* just error check */ | ||
219 | if (!IS_ERR(opp)) | ||
220 | ret = opp_disable(dev, 1000000000); | ||
221 | else | ||
222 | goto try_something_else; | ||
223 | } | ||
224 | |||
225 | 5. OPP Data Retrieval Functions | ||
226 | =============================== | ||
227 | Since OPP library abstracts away the OPP information, a set of functions to pull | ||
228 | information from the OPP structure is necessary. Once an OPP pointer is | ||
229 | retrieved using the search functions, the following functions can be used by SoC | ||
230 | framework to retrieve the information represented inside the OPP layer. | ||
231 | |||
232 | opp_get_voltage - Retrieve the voltage represented by the opp pointer. | ||
233 | Example: At a cpufreq transition to a different frequency, SoC | ||
234 | framework requires to set the voltage represented by the OPP using | ||
235 | the regulator framework to the Power Management chip providing the | ||
236 | voltage. | ||
237 | soc_switch_to_freq_voltage(freq) | ||
238 | { | ||
239 | /* do things */ | ||
240 | rcu_read_lock(); | ||
241 | opp = opp_find_freq_ceil(dev, &freq); | ||
242 | v = opp_get_voltage(opp); | ||
243 | rcu_read_unlock(); | ||
244 | if (v) | ||
245 | regulator_set_voltage(.., v); | ||
246 | /* do other things */ | ||
247 | } | ||
248 | |||
249 | opp_get_freq - Retrieve the freq represented by the opp pointer. | ||
250 | Example: Lets say the SoC framework uses a couple of helper functions | ||
251 | we could pass opp pointers instead of doing additional parameters to | ||
252 | handle quiet a bit of data parameters. | ||
253 | soc_cpufreq_target(..) | ||
254 | { | ||
255 | /* do things.. */ | ||
256 | max_freq = ULONG_MAX; | ||
257 | rcu_read_lock(); | ||
258 | max_opp = opp_find_freq_floor(dev,&max_freq); | ||
259 | requested_opp = opp_find_freq_ceil(dev,&freq); | ||
260 | if (!IS_ERR(max_opp) && !IS_ERR(requested_opp)) | ||
261 | r = soc_test_validity(max_opp, requested_opp); | ||
262 | rcu_read_unlock(); | ||
263 | /* do other things */ | ||
264 | } | ||
265 | soc_test_validity(..) | ||
266 | { | ||
267 | if(opp_get_voltage(max_opp) < opp_get_voltage(requested_opp)) | ||
268 | return -EINVAL; | ||
269 | if(opp_get_freq(max_opp) < opp_get_freq(requested_opp)) | ||
270 | return -EINVAL; | ||
271 | /* do things.. */ | ||
272 | } | ||
273 | |||
274 | opp_get_opp_count - Retrieve the number of available opps for a device | ||
275 | Example: Lets say a co-processor in the SoC needs to know the available | ||
276 | frequencies in a table, the main processor can notify as following: | ||
277 | soc_notify_coproc_available_frequencies() | ||
278 | { | ||
279 | /* Do things */ | ||
280 | rcu_read_lock(); | ||
281 | num_available = opp_get_opp_count(dev); | ||
282 | speeds = kzalloc(sizeof(u32) * num_available, GFP_KERNEL); | ||
283 | /* populate the table in increasing order */ | ||
284 | freq = 0; | ||
285 | while (!IS_ERR(opp = opp_find_freq_ceil(dev, &freq))) { | ||
286 | speeds[i] = freq; | ||
287 | freq++; | ||
288 | i++; | ||
289 | } | ||
290 | rcu_read_unlock(); | ||
291 | |||
292 | soc_notify_coproc(AVAILABLE_FREQs, speeds, num_available); | ||
293 | /* Do other things */ | ||
294 | } | ||
295 | |||
296 | 6. Cpufreq Table Generation | ||
297 | =========================== | ||
298 | opp_init_cpufreq_table - cpufreq framework typically is initialized with | ||
299 | cpufreq_frequency_table_cpuinfo which is provided with the list of | ||
300 | frequencies that are available for operation. This function provides | ||
301 | a ready to use conversion routine to translate the OPP layer's internal | ||
302 | information about the available frequencies into a format readily | ||
303 | providable to cpufreq. | ||
304 | |||
305 | WARNING: Do not use this function in interrupt context. | ||
306 | |||
307 | Example: | ||
308 | soc_pm_init() | ||
309 | { | ||
310 | /* Do things */ | ||
311 | r = opp_init_cpufreq_table(dev, &freq_table); | ||
312 | if (!r) | ||
313 | cpufreq_frequency_table_cpuinfo(policy, freq_table); | ||
314 | /* Do other things */ | ||
315 | } | ||
316 | |||
317 | NOTE: This function is available only if CONFIG_CPU_FREQ is enabled in | ||
318 | addition to CONFIG_PM as power management feature is required to | ||
319 | dynamically scale voltage and frequency in a system. | ||
320 | |||
321 | 7. Data Structures | ||
322 | ================== | ||
323 | Typically an SoC contains multiple voltage domains which are variable. Each | ||
324 | domain is represented by a device pointer. The relationship to OPP can be | ||
325 | represented as follows: | ||
326 | SoC | ||
327 | |- device 1 | ||
328 | | |- opp 1 (availability, freq, voltage) | ||
329 | | |- opp 2 .. | ||
330 | ... ... | ||
331 | | `- opp n .. | ||
332 | |- device 2 | ||
333 | ... | ||
334 | `- device m | ||
335 | |||
336 | OPP library maintains a internal list that the SoC framework populates and | ||
337 | accessed by various functions as described above. However, the structures | ||
338 | representing the actual OPPs and domains are internal to the OPP library itself | ||
339 | to allow for suitable abstraction reusable across systems. | ||
340 | |||
341 | struct opp - The internal data structure of OPP library which is used to | ||
342 | represent an OPP. In addition to the freq, voltage, availability | ||
343 | information, it also contains internal book keeping information required | ||
344 | for the OPP library to operate on. Pointer to this structure is | ||
345 | provided back to the users such as SoC framework to be used as a | ||
346 | identifier for OPP in the interactions with OPP layer. | ||
347 | |||
348 | WARNING: The struct opp pointer should not be parsed or modified by the | ||
349 | users. The defaults of for an instance is populated by opp_add, but the | ||
350 | availability of the OPP can be modified by opp_enable/disable functions. | ||
351 | |||
352 | struct device - This is used to identify a domain to the OPP layer. The | ||
353 | nature of the device and it's implementation is left to the user of | ||
354 | OPP library such as the SoC framework. | ||
355 | |||
356 | Overall, in a simplistic view, the data structure operations is represented as | ||
357 | following: | ||
358 | |||
359 | Initialization / modification: | ||
360 | +-----+ /- opp_enable | ||
361 | opp_add --> | opp | <------- | ||
362 | | +-----+ \- opp_disable | ||
363 | \-------> domain_info(device) | ||
364 | |||
365 | Search functions: | ||
366 | /-- opp_find_freq_ceil ---\ +-----+ | ||
367 | domain_info<---- opp_find_freq_exact -----> | opp | | ||
368 | \-- opp_find_freq_floor ---/ +-----+ | ||
369 | |||
370 | Retrieval functions: | ||
371 | +-----+ /- opp_get_voltage | ||
372 | | opp | <--- | ||
373 | +-----+ \- opp_get_freq | ||
374 | |||
375 | domain_info <- opp_get_opp_count | ||
diff --git a/Documentation/power/regulator/overview.txt b/Documentation/power/regulator/overview.txt index 9363e056188..8ed17587a74 100644 --- a/Documentation/power/regulator/overview.txt +++ b/Documentation/power/regulator/overview.txt | |||
@@ -13,7 +13,7 @@ regulators (where voltage output is controllable) and current sinks (where | |||
13 | current limit is controllable). | 13 | current limit is controllable). |
14 | 14 | ||
15 | (C) 2008 Wolfson Microelectronics PLC. | 15 | (C) 2008 Wolfson Microelectronics PLC. |
16 | Author: Liam Girdwood <lg@opensource.wolfsonmicro.com> | 16 | Author: Liam Girdwood <lrg@slimlogic.co.uk> |
17 | 17 | ||
18 | 18 | ||
19 | Nomenclature | 19 | Nomenclature |
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 55b859b3bc7..489e9bacd16 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt | |||
@@ -1,6 +1,7 @@ | |||
1 | Run-time Power Management Framework for I/O Devices | 1 | Run-time Power Management Framework for I/O Devices |
2 | 2 | ||
3 | (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. | 3 | (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. |
4 | (C) 2010 Alan Stern <stern@rowland.harvard.edu> | ||
4 | 5 | ||
5 | 1. Introduction | 6 | 1. Introduction |
6 | 7 | ||
@@ -157,7 +158,8 @@ rules: | |||
157 | to execute it, the other callbacks will not be executed for the same device. | 158 | to execute it, the other callbacks will not be executed for the same device. |
158 | 159 | ||
159 | * A request to execute ->runtime_resume() will cancel any pending or | 160 | * A request to execute ->runtime_resume() will cancel any pending or |
160 | scheduled requests to execute the other callbacks for the same device. | 161 | scheduled requests to execute the other callbacks for the same device, |
162 | except for scheduled autosuspends. | ||
161 | 163 | ||
162 | 3. Run-time PM Device Fields | 164 | 3. Run-time PM Device Fields |
163 | 165 | ||
@@ -165,7 +167,7 @@ The following device run-time PM fields are present in 'struct dev_pm_info', as | |||
165 | defined in include/linux/pm.h: | 167 | defined in include/linux/pm.h: |
166 | 168 | ||
167 | struct timer_list suspend_timer; | 169 | struct timer_list suspend_timer; |
168 | - timer used for scheduling (delayed) suspend request | 170 | - timer used for scheduling (delayed) suspend and autosuspend requests |
169 | 171 | ||
170 | unsigned long timer_expires; | 172 | unsigned long timer_expires; |
171 | - timer expiration time, in jiffies (if this is different from zero, the | 173 | - timer expiration time, in jiffies (if this is different from zero, the |
@@ -230,6 +232,28 @@ defined in include/linux/pm.h: | |||
230 | interface; it may only be modified with the help of the pm_runtime_allow() | 232 | interface; it may only be modified with the help of the pm_runtime_allow() |
231 | and pm_runtime_forbid() helper functions | 233 | and pm_runtime_forbid() helper functions |
232 | 234 | ||
235 | unsigned int no_callbacks; | ||
236 | - indicates that the device does not use the run-time PM callbacks (see | ||
237 | Section 8); it may be modified only by the pm_runtime_no_callbacks() | ||
238 | helper function | ||
239 | |||
240 | unsigned int use_autosuspend; | ||
241 | - indicates that the device's driver supports delayed autosuspend (see | ||
242 | Section 9); it may be modified only by the | ||
243 | pm_runtime{_dont}_use_autosuspend() helper functions | ||
244 | |||
245 | unsigned int timer_autosuspends; | ||
246 | - indicates that the PM core should attempt to carry out an autosuspend | ||
247 | when the timer expires rather than a normal suspend | ||
248 | |||
249 | int autosuspend_delay; | ||
250 | - the delay time (in milliseconds) to be used for autosuspend | ||
251 | |||
252 | unsigned long last_busy; | ||
253 | - the time (in jiffies) when the pm_runtime_mark_last_busy() helper | ||
254 | function was last called for this device; used in calculating inactivity | ||
255 | periods for autosuspend | ||
256 | |||
233 | All of the above fields are members of the 'power' member of 'struct device'. | 257 | All of the above fields are members of the 'power' member of 'struct device'. |
234 | 258 | ||
235 | 4. Run-time PM Device Helper Functions | 259 | 4. Run-time PM Device Helper Functions |
@@ -255,6 +279,12 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: | |||
255 | error code on failure, where -EAGAIN or -EBUSY means it is safe to attempt | 279 | error code on failure, where -EAGAIN or -EBUSY means it is safe to attempt |
256 | to suspend the device again in future | 280 | to suspend the device again in future |
257 | 281 | ||
282 | int pm_runtime_autosuspend(struct device *dev); | ||
283 | - same as pm_runtime_suspend() except that the autosuspend delay is taken | ||
284 | into account; if pm_runtime_autosuspend_expiration() says the delay has | ||
285 | not yet expired then an autosuspend is scheduled for the appropriate time | ||
286 | and 0 is returned | ||
287 | |||
258 | int pm_runtime_resume(struct device *dev); | 288 | int pm_runtime_resume(struct device *dev); |
259 | - execute the subsystem-level resume callback for the device; returns 0 on | 289 | - execute the subsystem-level resume callback for the device; returns 0 on |
260 | success, 1 if the device's run-time PM status was already 'active' or | 290 | success, 1 if the device's run-time PM status was already 'active' or |
@@ -267,6 +297,11 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: | |||
267 | device (the request is represented by a work item in pm_wq); returns 0 on | 297 | device (the request is represented by a work item in pm_wq); returns 0 on |
268 | success or error code if the request has not been queued up | 298 | success or error code if the request has not been queued up |
269 | 299 | ||
300 | int pm_request_autosuspend(struct device *dev); | ||
301 | - schedule the execution of the subsystem-level suspend callback for the | ||
302 | device when the autosuspend delay has expired; if the delay has already | ||
303 | expired then the work item is queued up immediately | ||
304 | |||
270 | int pm_schedule_suspend(struct device *dev, unsigned int delay); | 305 | int pm_schedule_suspend(struct device *dev, unsigned int delay); |
271 | - schedule the execution of the subsystem-level suspend callback for the | 306 | - schedule the execution of the subsystem-level suspend callback for the |
272 | device in future, where 'delay' is the time to wait before queuing up a | 307 | device in future, where 'delay' is the time to wait before queuing up a |
@@ -298,12 +333,20 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: | |||
298 | - decrement the device's usage counter | 333 | - decrement the device's usage counter |
299 | 334 | ||
300 | int pm_runtime_put(struct device *dev); | 335 | int pm_runtime_put(struct device *dev); |
301 | - decrement the device's usage counter, run pm_request_idle(dev) and return | 336 | - decrement the device's usage counter; if the result is 0 then run |
302 | its result | 337 | pm_request_idle(dev) and return its result |
338 | |||
339 | int pm_runtime_put_autosuspend(struct device *dev); | ||
340 | - decrement the device's usage counter; if the result is 0 then run | ||
341 | pm_request_autosuspend(dev) and return its result | ||
303 | 342 | ||
304 | int pm_runtime_put_sync(struct device *dev); | 343 | int pm_runtime_put_sync(struct device *dev); |
305 | - decrement the device's usage counter, run pm_runtime_idle(dev) and return | 344 | - decrement the device's usage counter; if the result is 0 then run |
306 | its result | 345 | pm_runtime_idle(dev) and return its result |
346 | |||
347 | int pm_runtime_put_sync_autosuspend(struct device *dev); | ||
348 | - decrement the device's usage counter; if the result is 0 then run | ||
349 | pm_runtime_autosuspend(dev) and return its result | ||
307 | 350 | ||
308 | void pm_runtime_enable(struct device *dev); | 351 | void pm_runtime_enable(struct device *dev); |
309 | - enable the run-time PM helper functions to run the device bus type's | 352 | - enable the run-time PM helper functions to run the device bus type's |
@@ -349,19 +392,51 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: | |||
349 | counter (used by the /sys/devices/.../power/control interface to | 392 | counter (used by the /sys/devices/.../power/control interface to |
350 | effectively prevent the device from being power managed at run time) | 393 | effectively prevent the device from being power managed at run time) |
351 | 394 | ||
395 | void pm_runtime_no_callbacks(struct device *dev); | ||
396 | - set the power.no_callbacks flag for the device and remove the run-time | ||
397 | PM attributes from /sys/devices/.../power (or prevent them from being | ||
398 | added when the device is registered) | ||
399 | |||
400 | void pm_runtime_mark_last_busy(struct device *dev); | ||
401 | - set the power.last_busy field to the current time | ||
402 | |||
403 | void pm_runtime_use_autosuspend(struct device *dev); | ||
404 | - set the power.use_autosuspend flag, enabling autosuspend delays | ||
405 | |||
406 | void pm_runtime_dont_use_autosuspend(struct device *dev); | ||
407 | - clear the power.use_autosuspend flag, disabling autosuspend delays | ||
408 | |||
409 | void pm_runtime_set_autosuspend_delay(struct device *dev, int delay); | ||
410 | - set the power.autosuspend_delay value to 'delay' (expressed in | ||
411 | milliseconds); if 'delay' is negative then run-time suspends are | ||
412 | prevented | ||
413 | |||
414 | unsigned long pm_runtime_autosuspend_expiration(struct device *dev); | ||
415 | - calculate the time when the current autosuspend delay period will expire, | ||
416 | based on power.last_busy and power.autosuspend_delay; if the delay time | ||
417 | is 1000 ms or larger then the expiration time is rounded up to the | ||
418 | nearest second; returns 0 if the delay period has already expired or | ||
419 | power.use_autosuspend isn't set, otherwise returns the expiration time | ||
420 | in jiffies | ||
421 | |||
352 | It is safe to execute the following helper functions from interrupt context: | 422 | It is safe to execute the following helper functions from interrupt context: |
353 | 423 | ||
354 | pm_request_idle() | 424 | pm_request_idle() |
425 | pm_request_autosuspend() | ||
355 | pm_schedule_suspend() | 426 | pm_schedule_suspend() |
356 | pm_request_resume() | 427 | pm_request_resume() |
357 | pm_runtime_get_noresume() | 428 | pm_runtime_get_noresume() |
358 | pm_runtime_get() | 429 | pm_runtime_get() |
359 | pm_runtime_put_noidle() | 430 | pm_runtime_put_noidle() |
360 | pm_runtime_put() | 431 | pm_runtime_put() |
432 | pm_runtime_put_autosuspend() | ||
433 | pm_runtime_enable() | ||
361 | pm_suspend_ignore_children() | 434 | pm_suspend_ignore_children() |
362 | pm_runtime_set_active() | 435 | pm_runtime_set_active() |
363 | pm_runtime_set_suspended() | 436 | pm_runtime_set_suspended() |
364 | pm_runtime_enable() | 437 | pm_runtime_suspended() |
438 | pm_runtime_mark_last_busy() | ||
439 | pm_runtime_autosuspend_expiration() | ||
365 | 440 | ||
366 | 5. Run-time PM Initialization, Device Probing and Removal | 441 | 5. Run-time PM Initialization, Device Probing and Removal |
367 | 442 | ||
@@ -524,3 +599,141 @@ poweroff and run-time suspend callback, and similarly for system resume, thaw, | |||
524 | restore, and run-time resume, can achieve this with the help of the | 599 | restore, and run-time resume, can achieve this with the help of the |
525 | UNIVERSAL_DEV_PM_OPS macro defined in include/linux/pm.h (possibly setting its | 600 | UNIVERSAL_DEV_PM_OPS macro defined in include/linux/pm.h (possibly setting its |
526 | last argument to NULL). | 601 | last argument to NULL). |
602 | |||
603 | 8. "No-Callback" Devices | ||
604 | |||
605 | Some "devices" are only logical sub-devices of their parent and cannot be | ||
606 | power-managed on their own. (The prototype example is a USB interface. Entire | ||
607 | USB devices can go into low-power mode or send wake-up requests, but neither is | ||
608 | possible for individual interfaces.) The drivers for these devices have no | ||
609 | need of run-time PM callbacks; if the callbacks did exist, ->runtime_suspend() | ||
610 | and ->runtime_resume() would always return 0 without doing anything else and | ||
611 | ->runtime_idle() would always call pm_runtime_suspend(). | ||
612 | |||
613 | Subsystems can tell the PM core about these devices by calling | ||
614 | pm_runtime_no_callbacks(). This should be done after the device structure is | ||
615 | initialized and before it is registered (although after device registration is | ||
616 | also okay). The routine will set the device's power.no_callbacks flag and | ||
617 | prevent the non-debugging run-time PM sysfs attributes from being created. | ||
618 | |||
619 | When power.no_callbacks is set, the PM core will not invoke the | ||
620 | ->runtime_idle(), ->runtime_suspend(), or ->runtime_resume() callbacks. | ||
621 | Instead it will assume that suspends and resumes always succeed and that idle | ||
622 | devices should be suspended. | ||
623 | |||
624 | As a consequence, the PM core will never directly inform the device's subsystem | ||
625 | or driver about run-time power changes. Instead, the driver for the device's | ||
626 | parent must take responsibility for telling the device's driver when the | ||
627 | parent's power state changes. | ||
628 | |||
629 | 9. Autosuspend, or automatically-delayed suspends | ||
630 | |||
631 | Changing a device's power state isn't free; it requires both time and energy. | ||
632 | A device should be put in a low-power state only when there's some reason to | ||
633 | think it will remain in that state for a substantial time. A common heuristic | ||
634 | says that a device which hasn't been used for a while is liable to remain | ||
635 | unused; following this advice, drivers should not allow devices to be suspended | ||
636 | at run-time until they have been inactive for some minimum period. Even when | ||
637 | the heuristic ends up being non-optimal, it will still prevent devices from | ||
638 | "bouncing" too rapidly between low-power and full-power states. | ||
639 | |||
640 | The term "autosuspend" is an historical remnant. It doesn't mean that the | ||
641 | device is automatically suspended (the subsystem or driver still has to call | ||
642 | the appropriate PM routines); rather it means that run-time suspends will | ||
643 | automatically be delayed until the desired period of inactivity has elapsed. | ||
644 | |||
645 | Inactivity is determined based on the power.last_busy field. Drivers should | ||
646 | call pm_runtime_mark_last_busy() to update this field after carrying out I/O, | ||
647 | typically just before calling pm_runtime_put_autosuspend(). The desired length | ||
648 | of the inactivity period is a matter of policy. Subsystems can set this length | ||
649 | initially by calling pm_runtime_set_autosuspend_delay(), but after device | ||
650 | registration the length should be controlled by user space, using the | ||
651 | /sys/devices/.../power/autosuspend_delay_ms attribute. | ||
652 | |||
653 | In order to use autosuspend, subsystems or drivers must call | ||
654 | pm_runtime_use_autosuspend() (preferably before registering the device), and | ||
655 | thereafter they should use the various *_autosuspend() helper functions instead | ||
656 | of the non-autosuspend counterparts: | ||
657 | |||
658 | Instead of: pm_runtime_suspend use: pm_runtime_autosuspend; | ||
659 | Instead of: pm_schedule_suspend use: pm_request_autosuspend; | ||
660 | Instead of: pm_runtime_put use: pm_runtime_put_autosuspend; | ||
661 | Instead of: pm_runtime_put_sync use: pm_runtime_put_sync_autosuspend. | ||
662 | |||
663 | Drivers may also continue to use the non-autosuspend helper functions; they | ||
664 | will behave normally, not taking the autosuspend delay into account. | ||
665 | Similarly, if the power.use_autosuspend field isn't set then the autosuspend | ||
666 | helper functions will behave just like the non-autosuspend counterparts. | ||
667 | |||
668 | The implementation is well suited for asynchronous use in interrupt contexts. | ||
669 | However such use inevitably involves races, because the PM core can't | ||
670 | synchronize ->runtime_suspend() callbacks with the arrival of I/O requests. | ||
671 | This synchronization must be handled by the driver, using its private lock. | ||
672 | Here is a schematic pseudo-code example: | ||
673 | |||
674 | foo_read_or_write(struct foo_priv *foo, void *data) | ||
675 | { | ||
676 | lock(&foo->private_lock); | ||
677 | add_request_to_io_queue(foo, data); | ||
678 | if (foo->num_pending_requests++ == 0) | ||
679 | pm_runtime_get(&foo->dev); | ||
680 | if (!foo->is_suspended) | ||
681 | foo_process_next_request(foo); | ||
682 | unlock(&foo->private_lock); | ||
683 | } | ||
684 | |||
685 | foo_io_completion(struct foo_priv *foo, void *req) | ||
686 | { | ||
687 | lock(&foo->private_lock); | ||
688 | if (--foo->num_pending_requests == 0) { | ||
689 | pm_runtime_mark_last_busy(&foo->dev); | ||
690 | pm_runtime_put_autosuspend(&foo->dev); | ||
691 | } else { | ||
692 | foo_process_next_request(foo); | ||
693 | } | ||
694 | unlock(&foo->private_lock); | ||
695 | /* Send req result back to the user ... */ | ||
696 | } | ||
697 | |||
698 | int foo_runtime_suspend(struct device *dev) | ||
699 | { | ||
700 | struct foo_priv foo = container_of(dev, ...); | ||
701 | int ret = 0; | ||
702 | |||
703 | lock(&foo->private_lock); | ||
704 | if (foo->num_pending_requests > 0) { | ||
705 | ret = -EBUSY; | ||
706 | } else { | ||
707 | /* ... suspend the device ... */ | ||
708 | foo->is_suspended = 1; | ||
709 | } | ||
710 | unlock(&foo->private_lock); | ||
711 | return ret; | ||
712 | } | ||
713 | |||
714 | int foo_runtime_resume(struct device *dev) | ||
715 | { | ||
716 | struct foo_priv foo = container_of(dev, ...); | ||
717 | |||
718 | lock(&foo->private_lock); | ||
719 | /* ... resume the device ... */ | ||
720 | foo->is_suspended = 0; | ||
721 | pm_runtime_mark_last_busy(&foo->dev); | ||
722 | if (foo->num_pending_requests > 0) | ||
723 | foo_process_requests(foo); | ||
724 | unlock(&foo->private_lock); | ||
725 | return 0; | ||
726 | } | ||
727 | |||
728 | The important point is that after foo_io_completion() asks for an autosuspend, | ||
729 | the foo_runtime_suspend() callback may race with foo_read_or_write(). | ||
730 | Therefore foo_runtime_suspend() has to check whether there are any pending I/O | ||
731 | requests (while holding the private lock) before allowing the suspend to | ||
732 | proceed. | ||
733 | |||
734 | In addition, the power.autosuspend_delay field can be changed by user space at | ||
735 | any time. If a driver cares about this, it can call | ||
736 | pm_runtime_autosuspend_expiration() from within the ->runtime_suspend() | ||
737 | callback while holding its private lock. If the function returns a nonzero | ||
738 | value then the delay has not yet expired and the callback should return | ||
739 | -EAGAIN. | ||
diff --git a/Documentation/power/s2ram.txt b/Documentation/power/s2ram.txt index 514b94fc931..1bdfa044377 100644 --- a/Documentation/power/s2ram.txt +++ b/Documentation/power/s2ram.txt | |||
@@ -49,6 +49,13 @@ machine that doesn't boot) is: | |||
49 | device (lspci and /sys/devices/pci* is your friend), and see if you can | 49 | device (lspci and /sys/devices/pci* is your friend), and see if you can |
50 | fix it, disable it, or trace into its resume function. | 50 | fix it, disable it, or trace into its resume function. |
51 | 51 | ||
52 | If no device matches the hash (or any matches appear to be false positives), | ||
53 | the culprit may be a device from a loadable kernel module that is not loaded | ||
54 | until after the hash is checked. You can check the hash against the current | ||
55 | devices again after more modules are loaded using sysfs: | ||
56 | |||
57 | cat /sys/power/pm_trace_dev_match | ||
58 | |||
52 | For example, the above happens to be the VGA device on my EVO, which I | 59 | For example, the above happens to be the VGA device on my EVO, which I |
53 | used to run with "radeonfb" (it's an ATI Radeon mobility). It turns out | 60 | used to run with "radeonfb" (it's an ATI Radeon mobility). It turns out |
54 | that "radeonfb" simply cannot resume that device - it tries to set the | 61 | that "radeonfb" simply cannot resume that device - it tries to set the |
diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt index 9d60ab717a7..ea718891a66 100644 --- a/Documentation/power/swsusp.txt +++ b/Documentation/power/swsusp.txt | |||
@@ -66,7 +66,8 @@ swsusp saves the state of the machine into active swaps and then reboots or | |||
66 | powerdowns. You must explicitly specify the swap partition to resume from with | 66 | powerdowns. You must explicitly specify the swap partition to resume from with |
67 | ``resume='' kernel option. If signature is found it loads and restores saved | 67 | ``resume='' kernel option. If signature is found it loads and restores saved |
68 | state. If the option ``noresume'' is specified as a boot parameter, it skips | 68 | state. If the option ``noresume'' is specified as a boot parameter, it skips |
69 | the resuming. | 69 | the resuming. If the option ``hibernate=nocompress'' is specified as a boot |
70 | parameter, it saves hibernation image without compression. | ||
70 | 71 | ||
71 | In the meantime while the system is suspended you should not add/remove any | 72 | In the meantime while the system is suspended you should not add/remove any |
72 | of the hardware, write to the filesystems, etc. | 73 | of the hardware, write to the filesystems, etc. |
diff --git a/Documentation/powerpc/dts-bindings/fsl/spi.txt b/Documentation/powerpc/dts-bindings/fsl/spi.txt index 80510c018ee..777abd7399d 100644 --- a/Documentation/powerpc/dts-bindings/fsl/spi.txt +++ b/Documentation/powerpc/dts-bindings/fsl/spi.txt | |||
@@ -1,7 +1,9 @@ | |||
1 | * SPI (Serial Peripheral Interface) | 1 | * SPI (Serial Peripheral Interface) |
2 | 2 | ||
3 | Required properties: | 3 | Required properties: |
4 | - cell-index : SPI controller index. | 4 | - cell-index : QE SPI subblock index. |
5 | 0: QE subblock SPI1 | ||
6 | 1: QE subblock SPI2 | ||
5 | - compatible : should be "fsl,spi". | 7 | - compatible : should be "fsl,spi". |
6 | - mode : the SPI operation mode, it can be "cpu" or "cpu-qe". | 8 | - mode : the SPI operation mode, it can be "cpu" or "cpu-qe". |
7 | - reg : Offset and length of the register set for the device | 9 | - reg : Offset and length of the register set for the device |
@@ -29,3 +31,23 @@ Example: | |||
29 | gpios = <&gpio 18 1 // device reg=<0> | 31 | gpios = <&gpio 18 1 // device reg=<0> |
30 | &gpio 19 1>; // device reg=<1> | 32 | &gpio 19 1>; // device reg=<1> |
31 | }; | 33 | }; |
34 | |||
35 | |||
36 | * eSPI (Enhanced Serial Peripheral Interface) | ||
37 | |||
38 | Required properties: | ||
39 | - compatible : should be "fsl,mpc8536-espi". | ||
40 | - reg : Offset and length of the register set for the device. | ||
41 | - interrupts : should contain eSPI interrupt, the device has one interrupt. | ||
42 | - fsl,espi-num-chipselects : the number of the chipselect signals. | ||
43 | |||
44 | Example: | ||
45 | spi@110000 { | ||
46 | #address-cells = <1>; | ||
47 | #size-cells = <0>; | ||
48 | compatible = "fsl,mpc8536-espi"; | ||
49 | reg = <0x110000 0x1000>; | ||
50 | interrupts = <53 0x2>; | ||
51 | interrupt-parent = <&mpic>; | ||
52 | fsl,espi-num-chipselects = <4>; | ||
53 | }; | ||
diff --git a/Documentation/sound/alsa/HD-Audio-Models.txt b/Documentation/sound/alsa/HD-Audio-Models.txt index ce46fa1e643..37c6aad5e59 100644 --- a/Documentation/sound/alsa/HD-Audio-Models.txt +++ b/Documentation/sound/alsa/HD-Audio-Models.txt | |||
@@ -296,6 +296,7 @@ Conexant 5051 | |||
296 | Conexant 5066 | 296 | Conexant 5066 |
297 | ============= | 297 | ============= |
298 | laptop Basic Laptop config (default) | 298 | laptop Basic Laptop config (default) |
299 | hp-laptop HP laptops, e g G60 | ||
299 | dell-laptop Dell laptops | 300 | dell-laptop Dell laptops |
300 | dell-vostro Dell Vostro | 301 | dell-vostro Dell Vostro |
301 | olpc-xo-1_5 OLPC XO 1.5 | 302 | olpc-xo-1_5 OLPC XO 1.5 |
diff --git a/Documentation/vm/page-types.c b/Documentation/vm/page-types.c index ccd951fa94e..cc96ee2666f 100644 --- a/Documentation/vm/page-types.c +++ b/Documentation/vm/page-types.c | |||
@@ -478,7 +478,7 @@ static void prepare_hwpoison_fd(void) | |||
478 | } | 478 | } |
479 | 479 | ||
480 | if (opt_unpoison && !hwpoison_forget_fd) { | 480 | if (opt_unpoison && !hwpoison_forget_fd) { |
481 | sprintf(buf, "%s/renew-pfn", hwpoison_debug_fs); | 481 | sprintf(buf, "%s/unpoison-pfn", hwpoison_debug_fs); |
482 | hwpoison_forget_fd = checked_open(buf, O_WRONLY); | 482 | hwpoison_forget_fd = checked_open(buf, O_WRONLY); |
483 | } | 483 | } |
484 | } | 484 | } |
diff --git a/Documentation/workqueue.txt b/Documentation/workqueue.txt new file mode 100644 index 00000000000..996a27d9b8d --- /dev/null +++ b/Documentation/workqueue.txt | |||
@@ -0,0 +1,381 @@ | |||
1 | |||
2 | Concurrency Managed Workqueue (cmwq) | ||
3 | |||
4 | September, 2010 Tejun Heo <tj@kernel.org> | ||
5 | Florian Mickler <florian@mickler.org> | ||
6 | |||
7 | CONTENTS | ||
8 | |||
9 | 1. Introduction | ||
10 | 2. Why cmwq? | ||
11 | 3. The Design | ||
12 | 4. Application Programming Interface (API) | ||
13 | 5. Example Execution Scenarios | ||
14 | 6. Guidelines | ||
15 | |||
16 | |||
17 | 1. Introduction | ||
18 | |||
19 | There are many cases where an asynchronous process execution context | ||
20 | is needed and the workqueue (wq) API is the most commonly used | ||
21 | mechanism for such cases. | ||
22 | |||
23 | When such an asynchronous execution context is needed, a work item | ||
24 | describing which function to execute is put on a queue. An | ||
25 | independent thread serves as the asynchronous execution context. The | ||
26 | queue is called workqueue and the thread is called worker. | ||
27 | |||
28 | While there are work items on the workqueue the worker executes the | ||
29 | functions associated with the work items one after the other. When | ||
30 | there is no work item left on the workqueue the worker becomes idle. | ||
31 | When a new work item gets queued, the worker begins executing again. | ||
32 | |||
33 | |||
34 | 2. Why cmwq? | ||
35 | |||
36 | In the original wq implementation, a multi threaded (MT) wq had one | ||
37 | worker thread per CPU and a single threaded (ST) wq had one worker | ||
38 | thread system-wide. A single MT wq needed to keep around the same | ||
39 | number of workers as the number of CPUs. The kernel grew a lot of MT | ||
40 | wq users over the years and with the number of CPU cores continuously | ||
41 | rising, some systems saturated the default 32k PID space just booting | ||
42 | up. | ||
43 | |||
44 | Although MT wq wasted a lot of resource, the level of concurrency | ||
45 | provided was unsatisfactory. The limitation was common to both ST and | ||
46 | MT wq albeit less severe on MT. Each wq maintained its own separate | ||
47 | worker pool. A MT wq could provide only one execution context per CPU | ||
48 | while a ST wq one for the whole system. Work items had to compete for | ||
49 | those very limited execution contexts leading to various problems | ||
50 | including proneness to deadlocks around the single execution context. | ||
51 | |||
52 | The tension between the provided level of concurrency and resource | ||
53 | usage also forced its users to make unnecessary tradeoffs like libata | ||
54 | choosing to use ST wq for polling PIOs and accepting an unnecessary | ||
55 | limitation that no two polling PIOs can progress at the same time. As | ||
56 | MT wq don't provide much better concurrency, users which require | ||
57 | higher level of concurrency, like async or fscache, had to implement | ||
58 | their own thread pool. | ||
59 | |||
60 | Concurrency Managed Workqueue (cmwq) is a reimplementation of wq with | ||
61 | focus on the following goals. | ||
62 | |||
63 | * Maintain compatibility with the original workqueue API. | ||
64 | |||
65 | * Use per-CPU unified worker pools shared by all wq to provide | ||
66 | flexible level of concurrency on demand without wasting a lot of | ||
67 | resource. | ||
68 | |||
69 | * Automatically regulate worker pool and level of concurrency so that | ||
70 | the API users don't need to worry about such details. | ||
71 | |||
72 | |||
73 | 3. The Design | ||
74 | |||
75 | In order to ease the asynchronous execution of functions a new | ||
76 | abstraction, the work item, is introduced. | ||
77 | |||
78 | A work item is a simple struct that holds a pointer to the function | ||
79 | that is to be executed asynchronously. Whenever a driver or subsystem | ||
80 | wants a function to be executed asynchronously it has to set up a work | ||
81 | item pointing to that function and queue that work item on a | ||
82 | workqueue. | ||
83 | |||
84 | Special purpose threads, called worker threads, execute the functions | ||
85 | off of the queue, one after the other. If no work is queued, the | ||
86 | worker threads become idle. These worker threads are managed in so | ||
87 | called thread-pools. | ||
88 | |||
89 | The cmwq design differentiates between the user-facing workqueues that | ||
90 | subsystems and drivers queue work items on and the backend mechanism | ||
91 | which manages thread-pool and processes the queued work items. | ||
92 | |||
93 | The backend is called gcwq. There is one gcwq for each possible CPU | ||
94 | and one gcwq to serve work items queued on unbound workqueues. | ||
95 | |||
96 | Subsystems and drivers can create and queue work items through special | ||
97 | workqueue API functions as they see fit. They can influence some | ||
98 | aspects of the way the work items are executed by setting flags on the | ||
99 | workqueue they are putting the work item on. These flags include | ||
100 | things like CPU locality, reentrancy, concurrency limits and more. To | ||
101 | get a detailed overview refer to the API description of | ||
102 | alloc_workqueue() below. | ||
103 | |||
104 | When a work item is queued to a workqueue, the target gcwq is | ||
105 | determined according to the queue parameters and workqueue attributes | ||
106 | and appended on the shared worklist of the gcwq. For example, unless | ||
107 | specifically overridden, a work item of a bound workqueue will be | ||
108 | queued on the worklist of exactly that gcwq that is associated to the | ||
109 | CPU the issuer is running on. | ||
110 | |||
111 | For any worker pool implementation, managing the concurrency level | ||
112 | (how many execution contexts are active) is an important issue. cmwq | ||
113 | tries to keep the concurrency at a minimal but sufficient level. | ||
114 | Minimal to save resources and sufficient in that the system is used at | ||
115 | its full capacity. | ||
116 | |||
117 | Each gcwq bound to an actual CPU implements concurrency management by | ||
118 | hooking into the scheduler. The gcwq is notified whenever an active | ||
119 | worker wakes up or sleeps and keeps track of the number of the | ||
120 | currently runnable workers. Generally, work items are not expected to | ||
121 | hog a CPU and consume many cycles. That means maintaining just enough | ||
122 | concurrency to prevent work processing from stalling should be | ||
123 | optimal. As long as there are one or more runnable workers on the | ||
124 | CPU, the gcwq doesn't start execution of a new work, but, when the | ||
125 | last running worker goes to sleep, it immediately schedules a new | ||
126 | worker so that the CPU doesn't sit idle while there are pending work | ||
127 | items. This allows using a minimal number of workers without losing | ||
128 | execution bandwidth. | ||
129 | |||
130 | Keeping idle workers around doesn't cost other than the memory space | ||
131 | for kthreads, so cmwq holds onto idle ones for a while before killing | ||
132 | them. | ||
133 | |||
134 | For an unbound wq, the above concurrency management doesn't apply and | ||
135 | the gcwq for the pseudo unbound CPU tries to start executing all work | ||
136 | items as soon as possible. The responsibility of regulating | ||
137 | concurrency level is on the users. There is also a flag to mark a | ||
138 | bound wq to ignore the concurrency management. Please refer to the | ||
139 | API section for details. | ||
140 | |||
141 | Forward progress guarantee relies on that workers can be created when | ||
142 | more execution contexts are necessary, which in turn is guaranteed | ||
143 | through the use of rescue workers. All work items which might be used | ||
144 | on code paths that handle memory reclaim are required to be queued on | ||
145 | wq's that have a rescue-worker reserved for execution under memory | ||
146 | pressure. Else it is possible that the thread-pool deadlocks waiting | ||
147 | for execution contexts to free up. | ||
148 | |||
149 | |||
150 | 4. Application Programming Interface (API) | ||
151 | |||
152 | alloc_workqueue() allocates a wq. The original create_*workqueue() | ||
153 | functions are deprecated and scheduled for removal. alloc_workqueue() | ||
154 | takes three arguments - @name, @flags and @max_active. @name is the | ||
155 | name of the wq and also used as the name of the rescuer thread if | ||
156 | there is one. | ||
157 | |||
158 | A wq no longer manages execution resources but serves as a domain for | ||
159 | forward progress guarantee, flush and work item attributes. @flags | ||
160 | and @max_active control how work items are assigned execution | ||
161 | resources, scheduled and executed. | ||
162 | |||
163 | @flags: | ||
164 | |||
165 | WQ_NON_REENTRANT | ||
166 | |||
167 | By default, a wq guarantees non-reentrance only on the same | ||
168 | CPU. A work item may not be executed concurrently on the same | ||
169 | CPU by multiple workers but is allowed to be executed | ||
170 | concurrently on multiple CPUs. This flag makes sure | ||
171 | non-reentrance is enforced across all CPUs. Work items queued | ||
172 | to a non-reentrant wq are guaranteed to be executed by at most | ||
173 | one worker system-wide at any given time. | ||
174 | |||
175 | WQ_UNBOUND | ||
176 | |||
177 | Work items queued to an unbound wq are served by a special | ||
178 | gcwq which hosts workers which are not bound to any specific | ||
179 | CPU. This makes the wq behave as a simple execution context | ||
180 | provider without concurrency management. The unbound gcwq | ||
181 | tries to start execution of work items as soon as possible. | ||
182 | Unbound wq sacrifices locality but is useful for the following | ||
183 | cases. | ||
184 | |||
185 | * Wide fluctuation in the concurrency level requirement is | ||
186 | expected and using bound wq may end up creating large number | ||
187 | of mostly unused workers across different CPUs as the issuer | ||
188 | hops through different CPUs. | ||
189 | |||
190 | * Long running CPU intensive workloads which can be better | ||
191 | managed by the system scheduler. | ||
192 | |||
193 | WQ_FREEZEABLE | ||
194 | |||
195 | A freezeable wq participates in the freeze phase of the system | ||
196 | suspend operations. Work items on the wq are drained and no | ||
197 | new work item starts execution until thawed. | ||
198 | |||
199 | WQ_MEM_RECLAIM | ||
200 | |||
201 | All wq which might be used in the memory reclaim paths _MUST_ | ||
202 | have this flag set. The wq is guaranteed to have at least one | ||
203 | execution context regardless of memory pressure. | ||
204 | |||
205 | WQ_HIGHPRI | ||
206 | |||
207 | Work items of a highpri wq are queued at the head of the | ||
208 | worklist of the target gcwq and start execution regardless of | ||
209 | the current concurrency level. In other words, highpri work | ||
210 | items will always start execution as soon as execution | ||
211 | resource is available. | ||
212 | |||
213 | Ordering among highpri work items is preserved - a highpri | ||
214 | work item queued after another highpri work item will start | ||
215 | execution after the earlier highpri work item starts. | ||
216 | |||
217 | Although highpri work items are not held back by other | ||
218 | runnable work items, they still contribute to the concurrency | ||
219 | level. Highpri work items in runnable state will prevent | ||
220 | non-highpri work items from starting execution. | ||
221 | |||
222 | This flag is meaningless for unbound wq. | ||
223 | |||
224 | WQ_CPU_INTENSIVE | ||
225 | |||
226 | Work items of a CPU intensive wq do not contribute to the | ||
227 | concurrency level. In other words, runnable CPU intensive | ||
228 | work items will not prevent other work items from starting | ||
229 | execution. This is useful for bound work items which are | ||
230 | expected to hog CPU cycles so that their execution is | ||
231 | regulated by the system scheduler. | ||
232 | |||
233 | Although CPU intensive work items don't contribute to the | ||
234 | concurrency level, start of their executions is still | ||
235 | regulated by the concurrency management and runnable | ||
236 | non-CPU-intensive work items can delay execution of CPU | ||
237 | intensive work items. | ||
238 | |||
239 | This flag is meaningless for unbound wq. | ||
240 | |||
241 | WQ_HIGHPRI | WQ_CPU_INTENSIVE | ||
242 | |||
243 | This combination makes the wq avoid interaction with | ||
244 | concurrency management completely and behave as a simple | ||
245 | per-CPU execution context provider. Work items queued on a | ||
246 | highpri CPU-intensive wq start execution as soon as resources | ||
247 | are available and don't affect execution of other work items. | ||
248 | |||
249 | @max_active: | ||
250 | |||
251 | @max_active determines the maximum number of execution contexts per | ||
252 | CPU which can be assigned to the work items of a wq. For example, | ||
253 | with @max_active of 16, at most 16 work items of the wq can be | ||
254 | executing at the same time per CPU. | ||
255 | |||
256 | Currently, for a bound wq, the maximum limit for @max_active is 512 | ||
257 | and the default value used when 0 is specified is 256. For an unbound | ||
258 | wq, the limit is higher of 512 and 4 * num_possible_cpus(). These | ||
259 | values are chosen sufficiently high such that they are not the | ||
260 | limiting factor while providing protection in runaway cases. | ||
261 | |||
262 | The number of active work items of a wq is usually regulated by the | ||
263 | users of the wq, more specifically, by how many work items the users | ||
264 | may queue at the same time. Unless there is a specific need for | ||
265 | throttling the number of active work items, specifying '0' is | ||
266 | recommended. | ||
267 | |||
268 | Some users depend on the strict execution ordering of ST wq. The | ||
269 | combination of @max_active of 1 and WQ_UNBOUND is used to achieve this | ||
270 | behavior. Work items on such wq are always queued to the unbound gcwq | ||
271 | and only one work item can be active at any given time thus achieving | ||
272 | the same ordering property as ST wq. | ||
273 | |||
274 | |||
275 | 5. Example Execution Scenarios | ||
276 | |||
277 | The following example execution scenarios try to illustrate how cmwq | ||
278 | behave under different configurations. | ||
279 | |||
280 | Work items w0, w1, w2 are queued to a bound wq q0 on the same CPU. | ||
281 | w0 burns CPU for 5ms then sleeps for 10ms then burns CPU for 5ms | ||
282 | again before finishing. w1 and w2 burn CPU for 5ms then sleep for | ||
283 | 10ms. | ||
284 | |||
285 | Ignoring all other tasks, works and processing overhead, and assuming | ||
286 | simple FIFO scheduling, the following is one highly simplified version | ||
287 | of possible sequences of events with the original wq. | ||
288 | |||
289 | TIME IN MSECS EVENT | ||
290 | 0 w0 starts and burns CPU | ||
291 | 5 w0 sleeps | ||
292 | 15 w0 wakes up and burns CPU | ||
293 | 20 w0 finishes | ||
294 | 20 w1 starts and burns CPU | ||
295 | 25 w1 sleeps | ||
296 | 35 w1 wakes up and finishes | ||
297 | 35 w2 starts and burns CPU | ||
298 | 40 w2 sleeps | ||
299 | 50 w2 wakes up and finishes | ||
300 | |||
301 | And with cmwq with @max_active >= 3, | ||
302 | |||
303 | TIME IN MSECS EVENT | ||
304 | 0 w0 starts and burns CPU | ||
305 | 5 w0 sleeps | ||
306 | 5 w1 starts and burns CPU | ||
307 | 10 w1 sleeps | ||
308 | 10 w2 starts and burns CPU | ||
309 | 15 w2 sleeps | ||
310 | 15 w0 wakes up and burns CPU | ||
311 | 20 w0 finishes | ||
312 | 20 w1 wakes up and finishes | ||
313 | 25 w2 wakes up and finishes | ||
314 | |||
315 | If @max_active == 2, | ||
316 | |||
317 | TIME IN MSECS EVENT | ||
318 | 0 w0 starts and burns CPU | ||
319 | 5 w0 sleeps | ||
320 | 5 w1 starts and burns CPU | ||
321 | 10 w1 sleeps | ||
322 | 15 w0 wakes up and burns CPU | ||
323 | 20 w0 finishes | ||
324 | 20 w1 wakes up and finishes | ||
325 | 20 w2 starts and burns CPU | ||
326 | 25 w2 sleeps | ||
327 | 35 w2 wakes up and finishes | ||
328 | |||
329 | Now, let's assume w1 and w2 are queued to a different wq q1 which has | ||
330 | WQ_HIGHPRI set, | ||
331 | |||
332 | TIME IN MSECS EVENT | ||
333 | 0 w1 and w2 start and burn CPU | ||
334 | 5 w1 sleeps | ||
335 | 10 w2 sleeps | ||
336 | 10 w0 starts and burns CPU | ||
337 | 15 w0 sleeps | ||
338 | 15 w1 wakes up and finishes | ||
339 | 20 w2 wakes up and finishes | ||
340 | 25 w0 wakes up and burns CPU | ||
341 | 30 w0 finishes | ||
342 | |||
343 | If q1 has WQ_CPU_INTENSIVE set, | ||
344 | |||
345 | TIME IN MSECS EVENT | ||
346 | 0 w0 starts and burns CPU | ||
347 | 5 w0 sleeps | ||
348 | 5 w1 and w2 start and burn CPU | ||
349 | 10 w1 sleeps | ||
350 | 15 w2 sleeps | ||
351 | 15 w0 wakes up and burns CPU | ||
352 | 20 w0 finishes | ||
353 | 20 w1 wakes up and finishes | ||
354 | 25 w2 wakes up and finishes | ||
355 | |||
356 | |||
357 | 6. Guidelines | ||
358 | |||
359 | * Do not forget to use WQ_MEM_RECLAIM if a wq may process work items | ||
360 | which are used during memory reclaim. Each wq with WQ_MEM_RECLAIM | ||
361 | set has an execution context reserved for it. If there is | ||
362 | dependency among multiple work items used during memory reclaim, | ||
363 | they should be queued to separate wq each with WQ_MEM_RECLAIM. | ||
364 | |||
365 | * Unless strict ordering is required, there is no need to use ST wq. | ||
366 | |||
367 | * Unless there is a specific need, using 0 for @max_active is | ||
368 | recommended. In most use cases, concurrency level usually stays | ||
369 | well under the default limit. | ||
370 | |||
371 | * A wq serves as a domain for forward progress guarantee | ||
372 | (WQ_MEM_RECLAIM, flush and work item attributes. Work items which | ||
373 | are not involved in memory reclaim and don't need to be flushed as a | ||
374 | part of a group of work items, and don't require any special | ||
375 | attribute, can use one of the system wq. There is no difference in | ||
376 | execution characteristics between using a dedicated wq and a system | ||
377 | wq. | ||
378 | |||
379 | * Unless work items are expected to consume a huge amount of CPU | ||
380 | cycles, using a bound wq is usually beneficial due to the increased | ||
381 | level of locality in wq operations and work item execution. | ||
diff --git a/Documentation/x86/x86_64/kernel-stacks b/Documentation/x86/x86_64/kernel-stacks index 5ad65d51fb9..a01eec5d1d0 100644 --- a/Documentation/x86/x86_64/kernel-stacks +++ b/Documentation/x86/x86_64/kernel-stacks | |||
@@ -18,9 +18,9 @@ specialized stacks contain no useful data. The main CPU stacks are: | |||
18 | Used for external hardware interrupts. If this is the first external | 18 | Used for external hardware interrupts. If this is the first external |
19 | hardware interrupt (i.e. not a nested hardware interrupt) then the | 19 | hardware interrupt (i.e. not a nested hardware interrupt) then the |
20 | kernel switches from the current task to the interrupt stack. Like | 20 | kernel switches from the current task to the interrupt stack. Like |
21 | the split thread and interrupt stacks on i386 (with CONFIG_4KSTACKS), | 21 | the split thread and interrupt stacks on i386, this gives more room |
22 | this gives more room for kernel interrupt processing without having | 22 | for kernel interrupt processing without having to increase the size |
23 | to increase the size of every per thread stack. | 23 | of every per thread stack. |
24 | 24 | ||
25 | The interrupt stack is also used when processing a softirq. | 25 | The interrupt stack is also used when processing a softirq. |
26 | 26 | ||