aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-firmware-sfi15
-rw-r--r--Documentation/DMA-API-HOWTO.txt85
-rw-r--r--Documentation/SubmittingDrivers5
-rw-r--r--Documentation/acpi/apei/einj.txt59
-rw-r--r--Documentation/arm/Samsung-S3C24XX/GPIO.txt81
-rw-r--r--Documentation/arm/Samsung-S3C24XX/Overview.txt15
-rw-r--r--Documentation/arm/Samsung/GPIO.txt42
-rw-r--r--Documentation/arm/Samsung/Overview.txt33
-rw-r--r--Documentation/cgroups/cgroups.txt2
-rw-r--r--Documentation/cgroups/memory.txt326
-rw-r--r--Documentation/feature-removal-schedule.txt10
-rw-r--r--Documentation/filesystems/Locking7
-rw-r--r--Documentation/filesystems/squashfs.txt32
-rw-r--r--Documentation/filesystems/vfs.txt9
-rw-r--r--Documentation/hwmon/dme173751
-rw-r--r--Documentation/hwmon/lm637
-rw-r--r--Documentation/hwmon/ltc42454
-rw-r--r--Documentation/hwmon/sysfs-interface13
-rw-r--r--Documentation/hwmon/tmp10226
-rw-r--r--Documentation/kernel-parameters.txt14
-rw-r--r--Documentation/vm/numa186
21 files changed, 818 insertions, 204 deletions
diff --git a/Documentation/ABI/testing/sysfs-firmware-sfi b/Documentation/ABI/testing/sysfs-firmware-sfi
new file mode 100644
index 000000000000..4be7d44aeacf
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-firmware-sfi
@@ -0,0 +1,15 @@
1What: /sys/firmware/sfi/tables/
2Date: May 2010
3Contact: Len Brown <lenb@kernel.org>
4Description:
5 SFI defines a number of small static memory tables
6 so the kernel can get platform information from firmware.
7
8 The tables are defined in the latest SFI specification:
9 http://simplefirmware.org/documentation
10
11 While the tables are used by the kernel, user-space
12 can observe them this way:
13
14 # cd /sys/firmware/sfi/tables
15 # cat $TABLENAME > $TABLENAME.bin
diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt
index 2e435adfbd6b..98ce51796f71 100644
--- a/Documentation/DMA-API-HOWTO.txt
+++ b/Documentation/DMA-API-HOWTO.txt
@@ -639,6 +639,36 @@ is planned to completely remove virt_to_bus() and bus_to_virt() as
639they are entirely deprecated. Some ports already do not provide these 639they are entirely deprecated. Some ports already do not provide these
640as it is impossible to correctly support them. 640as it is impossible to correctly support them.
641 641
642 Handling Errors
643
644DMA address space is limited on some architectures and an allocation
645failure can be determined by:
646
647- checking if dma_alloc_coherent returns NULL or dma_map_sg returns 0
648
649- checking the returned dma_addr_t of dma_map_single and dma_map_page
650 by using dma_mapping_error():
651
652 dma_addr_t dma_handle;
653
654 dma_handle = dma_map_single(dev, addr, size, direction);
655 if (dma_mapping_error(dev, dma_handle)) {
656 /*
657 * reduce current DMA mapping usage,
658 * delay and try again later or
659 * reset driver.
660 */
661 }
662
663Networking drivers must call dev_kfree_skb to free the socket buffer
664and return NETDEV_TX_OK if the DMA mapping fails on the transmit hook
665(ndo_start_xmit). This means that the socket buffer is just dropped in
666the failure case.
667
668SCSI drivers must return SCSI_MLQUEUE_HOST_BUSY if the DMA mapping
669fails in the queuecommand hook. This means that the SCSI subsystem
670passes the command to the driver again later.
671
642 Optimizing Unmap State Space Consumption 672 Optimizing Unmap State Space Consumption
643 673
644On many platforms, dma_unmap_{single,page}() is simply a nop. 674On many platforms, dma_unmap_{single,page}() is simply a nop.
@@ -703,42 +733,25 @@ to "Closing".
703 733
7041) Struct scatterlist requirements. 7341) Struct scatterlist requirements.
705 735
706 Struct scatterlist must contain, at a minimum, the following 736 Don't invent the architecture specific struct scatterlist; just use
707 members: 737 <asm-generic/scatterlist.h>. You need to enable
708 738 CONFIG_NEED_SG_DMA_LENGTH if the architecture supports IOMMUs
709 struct page *page; 739 (including software IOMMU).
710 unsigned int offset; 740
711 unsigned int length; 7412) ARCH_KMALLOC_MINALIGN
712 742
713 The base address is specified by a "page+offset" pair. 743 Architectures must ensure that kmalloc'ed buffer is
714 744 DMA-safe. Drivers and subsystems depend on it. If an architecture
715 Previous versions of struct scatterlist contained a "void *address" 745 isn't fully DMA-coherent (i.e. hardware doesn't ensure that data in
716 field that was sometimes used instead of page+offset. As of Linux 746 the CPU cache is identical to data in main memory),
717 2.5., page+offset is always used, and the "address" field has been 747 ARCH_KMALLOC_MINALIGN must be set so that the memory allocator
718 deleted. 748 makes sure that kmalloc'ed buffer doesn't share a cache line with
719 749 the others. See arch/arm/include/asm/cache.h as an example.
7202) More to come... 750
721 751 Note that ARCH_KMALLOC_MINALIGN is about DMA memory alignment
722 Handling Errors 752 constraints. You don't need to worry about the architecture data
723 753 alignment constraints (e.g. the alignment constraints about 64-bit
724DMA address space is limited on some architectures and an allocation 754 objects).
725failure can be determined by:
726
727- checking if dma_alloc_coherent returns NULL or dma_map_sg returns 0
728
729- checking the returned dma_addr_t of dma_map_single and dma_map_page
730 by using dma_mapping_error():
731
732 dma_addr_t dma_handle;
733
734 dma_handle = dma_map_single(dev, addr, size, direction);
735 if (dma_mapping_error(dev, dma_handle)) {
736 /*
737 * reduce current DMA mapping usage,
738 * delay and try again later or
739 * reset driver.
740 */
741 }
742 755
743 Closing 756 Closing
744 757
diff --git a/Documentation/SubmittingDrivers b/Documentation/SubmittingDrivers
index 99e72a81fa2f..4947fd8fb182 100644
--- a/Documentation/SubmittingDrivers
+++ b/Documentation/SubmittingDrivers
@@ -130,6 +130,8 @@ Linux kernel master tree:
130 ftp.??.kernel.org:/pub/linux/kernel/... 130 ftp.??.kernel.org:/pub/linux/kernel/...
131 ?? == your country code, such as "us", "uk", "fr", etc. 131 ?? == your country code, such as "us", "uk", "fr", etc.
132 132
133 http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git
134
133Linux kernel mailing list: 135Linux kernel mailing list:
134 linux-kernel@vger.kernel.org 136 linux-kernel@vger.kernel.org
135 [mail majordomo@vger.kernel.org to subscribe] 137 [mail majordomo@vger.kernel.org to subscribe]
@@ -160,3 +162,6 @@ How to NOT write kernel driver by Arjan van de Ven:
160 162
161Kernel Janitor: 163Kernel Janitor:
162 http://janitor.kernelnewbies.org/ 164 http://janitor.kernelnewbies.org/
165
166GIT, Fast Version Control System:
167 http://git-scm.com/
diff --git a/Documentation/acpi/apei/einj.txt b/Documentation/acpi/apei/einj.txt
new file mode 100644
index 000000000000..dfab71848dc8
--- /dev/null
+++ b/Documentation/acpi/apei/einj.txt
@@ -0,0 +1,59 @@
1 APEI Error INJection
2 ~~~~~~~~~~~~~~~~~~~~
3
4EINJ provides a hardware error injection mechanism
5It is very useful for debugging and testing of other APEI and RAS features.
6
7To use EINJ, make sure the following are enabled in your kernel
8configuration:
9
10CONFIG_DEBUG_FS
11CONFIG_ACPI_APEI
12CONFIG_ACPI_APEI_EINJ
13
14The user interface of EINJ is debug file system, under the
15directory apei/einj. The following files are provided.
16
17- available_error_type
18 Reading this file returns the error injection capability of the
19 platform, that is, which error types are supported. The error type
20 definition is as follow, the left field is the error type value, the
21 right field is error description.
22
23 0x00000001 Processor Correctable
24 0x00000002 Processor Uncorrectable non-fatal
25 0x00000004 Processor Uncorrectable fatal
26 0x00000008 Memory Correctable
27 0x00000010 Memory Uncorrectable non-fatal
28 0x00000020 Memory Uncorrectable fatal
29 0x00000040 PCI Express Correctable
30 0x00000080 PCI Express Uncorrectable fatal
31 0x00000100 PCI Express Uncorrectable non-fatal
32 0x00000200 Platform Correctable
33 0x00000400 Platform Uncorrectable non-fatal
34 0x00000800 Platform Uncorrectable fatal
35
36 The format of file contents are as above, except there are only the
37 available error type lines.
38
39- error_type
40 This file is used to set the error type value. The error type value
41 is defined in "available_error_type" description.
42
43- error_inject
44 Write any integer to this file to trigger the error
45 injection. Before this, please specify all necessary error
46 parameters.
47
48- param1
49 This file is used to set the first error parameter value. Effect of
50 parameter depends on error_type specified. For memory error, this is
51 physical memory address.
52
53- param2
54 This file is used to set the second error parameter value. Effect of
55 parameter depends on error_type specified. For memory error, this is
56 physical memory address mask.
57
58For more information about EINJ, please refer to ACPI specification
59version 4.0, section 17.5.
diff --git a/Documentation/arm/Samsung-S3C24XX/GPIO.txt b/Documentation/arm/Samsung-S3C24XX/GPIO.txt
index 2af2cf39915f..816d6071669e 100644
--- a/Documentation/arm/Samsung-S3C24XX/GPIO.txt
+++ b/Documentation/arm/Samsung-S3C24XX/GPIO.txt
@@ -12,6 +12,8 @@ Introduction
12 of the s3c2410 GPIO system, please read the Samsung provided 12 of the s3c2410 GPIO system, please read the Samsung provided
13 data-sheet/users manual to find out the complete list. 13 data-sheet/users manual to find out the complete list.
14 14
15 See Documentation/arm/Samsung/GPIO.txt for the core implemetation.
16
15 17
16GPIOLIB 18GPIOLIB
17------- 19-------
@@ -24,8 +26,60 @@ GPIOLIB
24 listed below will be removed (they may be marked as __deprecated 26 listed below will be removed (they may be marked as __deprecated
25 in the near future). 27 in the near future).
26 28
27 - s3c2410_gpio_getpin 29 The following functions now either have a s3c_ specific variant
28 - s3c2410_gpio_setpin 30 or are merged into gpiolib. See the definitions in
31 arch/arm/plat-samsung/include/plat/gpio-cfg.h:
32
33 s3c2410_gpio_setpin() gpio_set_value() or gpio_direction_output()
34 s3c2410_gpio_getpin() gpio_get_value() or gpio_direction_input()
35 s3c2410_gpio_getirq() gpio_to_irq()
36 s3c2410_gpio_cfgpin() s3c_gpio_cfgpin()
37 s3c2410_gpio_getcfg() s3c_gpio_getcfg()
38 s3c2410_gpio_pullup() s3c_gpio_setpull()
39
40
41GPIOLIB conversion
42------------------
43
44If you need to convert your board or driver to use gpiolib from the exiting
45s3c2410 api, then here are some notes on the process.
46
471) If your board is exclusively using an GPIO, say to control peripheral
48 power, then it will require to claim the gpio with gpio_request() before
49 it can use it.
50
51 It is recommended to check the return value, with at least WARN_ON()
52 during initialisation.
53
542) The s3c2410_gpio_cfgpin() can be directly replaced with s3c_gpio_cfgpin()
55 as they have the same arguments, and can either take the pin specific
56 values, or the more generic special-function-number arguments.
57
583) s3c2410_gpio_pullup() changs have the problem that whilst the
59 s3c2410_gpio_pullup(x, 1) can be easily translated to the
60 s3c_gpio_setpull(x, S3C_GPIO_PULL_NONE), the s3c2410_gpio_pullup(x, 0)
61 are not so easy.
62
63 The s3c2410_gpio_pullup(x, 0) case enables the pull-up (or in the case
64 of some of the devices, a pull-down) and as such the new API distinguishes
65 between the UP and DOWN case. There is currently no 'just turn on' setting
66 which may be required if this becomes a problem.
67
684) s3c2410_gpio_setpin() can be replaced by gpio_set_value(), the old call
69 does not implicitly configure the relevant gpio to output. The gpio
70 direction should be changed before using gpio_set_value().
71
725) s3c2410_gpio_getpin() is replaceable by gpio_get_value() if the pin
73 has been set to input. It is currently unknown what the behaviour is
74 when using gpio_get_value() on an output pin (s3c2410_gpio_getpin
75 would return the value the pin is supposed to be outputting).
76
776) s3c2410_gpio_getirq() should be directly replacable with the
78 gpio_to_irq() call.
79
80The s3c2410_gpio and gpio_ calls have always operated on the same gpio
81numberspace, so there is no problem with converting the gpio numbering
82between the calls.
29 83
30 84
31Headers 85Headers
@@ -54,6 +108,11 @@ PIN Numbers
54 eg S3C2410_GPA(0) or S3C2410_GPF(1). These defines are used to tell 108 eg S3C2410_GPA(0) or S3C2410_GPF(1). These defines are used to tell
55 the GPIO functions which pin is to be used. 109 the GPIO functions which pin is to be used.
56 110
111 With the conversion to gpiolib, there is no longer a direct conversion
112 from gpio pin number to register base address as in earlier kernels. This
113 is due to the number space required for newer SoCs where the later
114 GPIOs are not contiguous.
115
57 116
58Configuring a pin 117Configuring a pin
59----------------- 118-----------------
@@ -71,6 +130,8 @@ Configuring a pin
71 which would turn GPA(0) into the lowest Address line A0, and set 130 which would turn GPA(0) into the lowest Address line A0, and set
72 GPE(8) to be connected to the SDIO/MMC controller's SDDAT1 line. 131 GPE(8) to be connected to the SDIO/MMC controller's SDDAT1 line.
73 132
133 The s3c_gpio_cfgpin() call is a functional replacement for this call.
134
74 135
75Reading the current configuration 136Reading the current configuration
76--------------------------------- 137---------------------------------
@@ -82,6 +143,9 @@ Reading the current configuration
82 The return value will be from the same set of values which can be 143 The return value will be from the same set of values which can be
83 passed to s3c2410_gpio_cfgpin(). 144 passed to s3c2410_gpio_cfgpin().
84 145
146 The s3c_gpio_getcfg() call should be a functional replacement for
147 this call.
148
85 149
86Configuring a pull-up resistor 150Configuring a pull-up resistor
87------------------------------ 151------------------------------
@@ -95,6 +159,10 @@ Configuring a pull-up resistor
95 Where the to value is zero to set the pull-up off, and 1 to enable 159 Where the to value is zero to set the pull-up off, and 1 to enable
96 the specified pull-up. Any other values are currently undefined. 160 the specified pull-up. Any other values are currently undefined.
97 161
162 The s3c_gpio_setpull() offers similar functionality, but with the
163 ability to encode whether the pull is up or down. Currently there
164 is no 'just on' state, so up or down must be selected.
165
98 166
99Getting the state of a PIN 167Getting the state of a PIN
100-------------------------- 168--------------------------
@@ -106,6 +174,9 @@ Getting the state of a PIN
106 This will return either zero or non-zero. Do not count on this 174 This will return either zero or non-zero. Do not count on this
107 function returning 1 if the pin is set. 175 function returning 1 if the pin is set.
108 176
177 This call is now implemented by the relevant gpiolib calls, convert
178 your board or driver to use gpiolib.
179
109 180
110Setting the state of a PIN 181Setting the state of a PIN
111-------------------------- 182--------------------------
@@ -117,6 +188,9 @@ Setting the state of a PIN
117 Which sets the given pin to the value. Use 0 to write 0, and 1 to 188 Which sets the given pin to the value. Use 0 to write 0, and 1 to
118 set the output to 1. 189 set the output to 1.
119 190
191 This call is now implemented by the relevant gpiolib calls, convert
192 your board or driver to use gpiolib.
193
120 194
121Getting the IRQ number associated with a PIN 195Getting the IRQ number associated with a PIN
122-------------------------------------------- 196--------------------------------------------
@@ -128,6 +202,9 @@ Getting the IRQ number associated with a PIN
128 202
129 Note, not all pins have an IRQ. 203 Note, not all pins have an IRQ.
130 204
205 This call is now implemented by the relevant gpiolib calls, convert
206 your board or driver to use gpiolib.
207
131 208
132Authour 209Authour
133------- 210-------
diff --git a/Documentation/arm/Samsung-S3C24XX/Overview.txt b/Documentation/arm/Samsung-S3C24XX/Overview.txt
index 081892df4fda..c12bfc1a00c9 100644
--- a/Documentation/arm/Samsung-S3C24XX/Overview.txt
+++ b/Documentation/arm/Samsung-S3C24XX/Overview.txt
@@ -8,10 +8,16 @@ Introduction
8 8
9 The Samsung S3C24XX range of ARM9 System-on-Chip CPUs are supported 9 The Samsung S3C24XX range of ARM9 System-on-Chip CPUs are supported
10 by the 's3c2410' architecture of ARM Linux. Currently the S3C2410, 10 by the 's3c2410' architecture of ARM Linux. Currently the S3C2410,
11 S3C2412, S3C2413, S3C2440, S3C2442 and S3C2443 devices are supported. 11 S3C2412, S3C2413, S3C2416 S3C2440, S3C2442, S3C2443 and S3C2450 devices
12 are supported.
12 13
13 Support for the S3C2400 and S3C24A0 series are in progress. 14 Support for the S3C2400 and S3C24A0 series are in progress.
14 15
16 The S3C2416 and S3C2450 devices are very similar and S3C2450 support is
17 included under the arch/arm/mach-s3c2416 directory. Note, whilst core
18 support for these SoCs is in, work on some of the extra peripherals
19 and extra interrupts is still ongoing.
20
15 21
16Configuration 22Configuration
17------------- 23-------------
@@ -209,6 +215,13 @@ GPIO
209 Newer kernels carry GPIOLIB, and support is being moved towards 215 Newer kernels carry GPIOLIB, and support is being moved towards
210 this with some of the older support in line to be removed. 216 this with some of the older support in line to be removed.
211 217
218 As of v2.6.34, the move towards using gpiolib support is almost
219 complete, and very little of the old calls are left.
220
221 See Documentation/arm/Samsung-S3C24XX/GPIO.txt for the S3C24XX specific
222 support and Documentation/arm/Samsung/GPIO.txt for the core Samsung
223 implementation.
224
212 225
213Clock Management 226Clock Management
214---------------- 227----------------
diff --git a/Documentation/arm/Samsung/GPIO.txt b/Documentation/arm/Samsung/GPIO.txt
new file mode 100644
index 000000000000..05850c62abeb
--- /dev/null
+++ b/Documentation/arm/Samsung/GPIO.txt
@@ -0,0 +1,42 @@
1 Samsung GPIO implementation
2 ===========================
3
4Introduction
5------------
6
7This outlines the Samsung GPIO implementation and the architecture
8specfic calls provided alongisde the drivers/gpio core.
9
10
11S3C24XX (Legacy)
12----------------
13
14See Documentation/arm/Samsung-S3C24XX/GPIO.txt for more information
15about these devices. Their implementation is being brought into line
16with the core samsung implementation described in this document.
17
18
19GPIOLIB integration
20-------------------
21
22The gpio implementation uses gpiolib as much as possible, only providing
23specific calls for the items that require Samsung specific handling, such
24as pin special-function or pull resistor control.
25
26GPIO numbering is synchronised between the Samsung and gpiolib system.
27
28
29PIN configuration
30-----------------
31
32Pin configuration is specific to the Samsung architecutre, with each SoC
33registering the necessary information for the core gpio configuration
34implementation to configure pins as necessary.
35
36The s3c_gpio_cfgpin() and s3c_gpio_setpull() provide the means for a
37driver or machine to change gpio configuration.
38
39See arch/arm/plat-samsung/include/plat/gpio-cfg.h for more information
40on these functions.
41
42
diff --git a/Documentation/arm/Samsung/Overview.txt b/Documentation/arm/Samsung/Overview.txt
index 7cced1fea9c3..c3094ea51aa7 100644
--- a/Documentation/arm/Samsung/Overview.txt
+++ b/Documentation/arm/Samsung/Overview.txt
@@ -13,9 +13,10 @@ Introduction
13 13
14 - S3C24XX: See Documentation/arm/Samsung-S3C24XX/Overview.txt for full list 14 - S3C24XX: See Documentation/arm/Samsung-S3C24XX/Overview.txt for full list
15 - S3C64XX: S3C6400 and S3C6410 15 - S3C64XX: S3C6400 and S3C6410
16 - S5PC6440 16 - S5P6440
17 17 - S5P6442
18 S5PC100 and S5PC110 support is currently being merged 18 - S5PC100
19 - S5PC110 / S5PV210
19 20
20 21
21S3C24XX Systems 22S3C24XX Systems
@@ -35,7 +36,10 @@ Configuration
35 unifying all the SoCs into one kernel. 36 unifying all the SoCs into one kernel.
36 37
37 s5p6440_defconfig - S5P6440 specific default configuration 38 s5p6440_defconfig - S5P6440 specific default configuration
39 s5p6442_defconfig - S5P6442 specific default configuration
38 s5pc100_defconfig - S5PC100 specific default configuration 40 s5pc100_defconfig - S5PC100 specific default configuration
41 s5pc110_defconfig - S5PC110 specific default configuration
42 s5pv210_defconfig - S5PV210 specific default configuration
39 43
40 44
41Layout 45Layout
@@ -50,18 +54,27 @@ Layout
50 specific information. It contains the base clock, GPIO and device definitions 54 specific information. It contains the base clock, GPIO and device definitions
51 to get the system running. 55 to get the system running.
52 56
53 plat-s3c is the s3c24xx/s3c64xx platform directory, although it is currently
54 involved in other builds this will be phased out once the relevant code is
55 moved elsewhere.
56
57 plat-s3c24xx is for s3c24xx specific builds, see the S3C24XX docs. 57 plat-s3c24xx is for s3c24xx specific builds, see the S3C24XX docs.
58 58
59 plat-s3c64xx is for the s3c64xx specific bits, see the S3C24XX docs. 59 plat-s5p is for s5p specific builds, and contains common support for the
60 S5P specific systems. Not all S5Ps use all the features in this directory
61 due to differences in the hardware.
62
63
64Layout changes
65--------------
66
67 The old plat-s3c and plat-s5pc1xx directories have been removed, with
68 support moved to either plat-samsung or plat-s5p as necessary. These moves
69 where to simplify the include and dependency issues involved with having
70 so many different platform directories.
60 71
61 plat-s5p is for s5p specific builds, more to be added. 72 It was decided to remove plat-s5pc1xx as some of the support was already
73 in plat-s5p or plat-samsung, with the S5PC110 support added with S5PV210
74 the only user was the S5PC100. The S5PC100 specific items where moved to
75 arch/arm/mach-s5pc100.
62 76
63 77
64 [ to finish ]
65 78
66 79
67Port Contributors 80Port Contributors
diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
index 57444c2609fc..b34823ff1646 100644
--- a/Documentation/cgroups/cgroups.txt
+++ b/Documentation/cgroups/cgroups.txt
@@ -339,7 +339,7 @@ To mount a cgroup hierarchy with all available subsystems, type:
339The "xxx" is not interpreted by the cgroup code, but will appear in 339The "xxx" is not interpreted by the cgroup code, but will appear in
340/proc/mounts so may be any useful identifying string that you like. 340/proc/mounts so may be any useful identifying string that you like.
341 341
342To mount a cgroup hierarchy with just the cpuset and numtasks 342To mount a cgroup hierarchy with just the cpuset and memory
343subsystems, type: 343subsystems, type:
344# mount -t cgroup -o cpuset,memory hier1 /dev/cgroup 344# mount -t cgroup -o cpuset,memory hier1 /dev/cgroup
345 345
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 6cab1f29da4c..7781857dc940 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -1,18 +1,15 @@
1Memory Resource Controller 1Memory Resource Controller
2 2
3NOTE: The Memory Resource Controller has been generically been referred 3NOTE: The Memory Resource Controller has been generically been referred
4to as the memory controller in this document. Do not confuse memory controller 4 to as the memory controller in this document. Do not confuse memory
5used here with the memory controller that is used in hardware. 5 controller used here with the memory controller that is used in hardware.
6 6
7Salient features 7(For editors)
8 8In this document:
9a. Enable control of Anonymous, Page Cache (mapped and unmapped) and 9 When we mention a cgroup (cgroupfs's directory) with memory controller,
10 Swap Cache memory pages. 10 we call it "memory cgroup". When you see git-log and source code, you'll
11b. The infrastructure allows easy addition of other types of memory to control 11 see patch's title and function names tend to use "memcg".
12c. Provides *zero overhead* for non memory controller users 12 In this document, we avoid using it.
13d. Provides a double LRU: global memory pressure causes reclaim from the
14 global LRU; a cgroup on hitting a limit, reclaims from the per
15 cgroup LRU
16 13
17Benefits and Purpose of the memory controller 14Benefits and Purpose of the memory controller
18 15
@@ -33,6 +30,45 @@ d. A CD/DVD burner could control the amount of memory used by the
33e. There are several other use cases, find one or use the controller just 30e. There are several other use cases, find one or use the controller just
34 for fun (to learn and hack on the VM subsystem). 31 for fun (to learn and hack on the VM subsystem).
35 32
33Current Status: linux-2.6.34-mmotm(development version of 2010/April)
34
35Features:
36 - accounting anonymous pages, file caches, swap caches usage and limiting them.
37 - private LRU and reclaim routine. (system's global LRU and private LRU
38 work independently from each other)
39 - optionally, memory+swap usage can be accounted and limited.
40 - hierarchical accounting
41 - soft limit
42 - moving(recharging) account at moving a task is selectable.
43 - usage threshold notifier
44 - oom-killer disable knob and oom-notifier
45 - Root cgroup has no limit controls.
46
47 Kernel memory and Hugepages are not under control yet. We just manage
48 pages on LRU. To add more controls, we have to take care of performance.
49
50Brief summary of control files.
51
52 tasks # attach a task(thread) and show list of threads
53 cgroup.procs # show list of processes
54 cgroup.event_control # an interface for event_fd()
55 memory.usage_in_bytes # show current memory(RSS+Cache) usage.
56 memory.memsw.usage_in_bytes # show current memory+Swap usage
57 memory.limit_in_bytes # set/show limit of memory usage
58 memory.memsw.limit_in_bytes # set/show limit of memory+Swap usage
59 memory.failcnt # show the number of memory usage hits limits
60 memory.memsw.failcnt # show the number of memory+Swap hits limits
61 memory.max_usage_in_bytes # show max memory usage recorded
62 memory.memsw.usage_in_bytes # show max memory+Swap usage recorded
63 memory.soft_limit_in_bytes # set/show soft limit of memory usage
64 memory.stat # show various statistics
65 memory.use_hierarchy # set/show hierarchical account enabled
66 memory.force_empty # trigger forced move charge to parent
67 memory.swappiness # set/show swappiness parameter of vmscan
68 (See sysctl's vm.swappiness)
69 memory.move_charge_at_immigrate # set/show controls of moving charges
70 memory.oom_control # set/show oom controls.
71
361. History 721. History
37 73
38The memory controller has a long history. A request for comments for the memory 74The memory controller has a long history. A request for comments for the memory
@@ -106,14 +142,14 @@ the necessary data structures and check if the cgroup that is being charged
106is over its limit. If it is then reclaim is invoked on the cgroup. 142is over its limit. If it is then reclaim is invoked on the cgroup.
107More details can be found in the reclaim section of this document. 143More details can be found in the reclaim section of this document.
108If everything goes well, a page meta-data-structure called page_cgroup is 144If everything goes well, a page meta-data-structure called page_cgroup is
109allocated and associated with the page. This routine also adds the page to 145updated. page_cgroup has its own LRU on cgroup.
110the per cgroup LRU. 146(*) page_cgroup structure is allocated at boot/memory-hotplug time.
111 147
1122.2.1 Accounting details 1482.2.1 Accounting details
113 149
114All mapped anon pages (RSS) and cache pages (Page Cache) are accounted. 150All mapped anon pages (RSS) and cache pages (Page Cache) are accounted.
115(some pages which never be reclaimable and will not be on global LRU 151Some pages which are never reclaimable and will not be on the global LRU
116 are not accounted. we just accounts pages under usual vm management.) 152are not accounted. We just account pages under usual VM management.
117 153
118RSS pages are accounted at page_fault unless they've already been accounted 154RSS pages are accounted at page_fault unless they've already been accounted
119for earlier. A file page will be accounted for as Page Cache when it's 155for earlier. A file page will be accounted for as Page Cache when it's
@@ -121,12 +157,19 @@ inserted into inode (radix-tree). While it's mapped into the page tables of
121processes, duplicate accounting is carefully avoided. 157processes, duplicate accounting is carefully avoided.
122 158
123A RSS page is unaccounted when it's fully unmapped. A PageCache page is 159A RSS page is unaccounted when it's fully unmapped. A PageCache page is
124unaccounted when it's removed from radix-tree. 160unaccounted when it's removed from radix-tree. Even if RSS pages are fully
161unmapped (by kswapd), they may exist as SwapCache in the system until they
162are really freed. Such SwapCaches also also accounted.
163A swapped-in page is not accounted until it's mapped.
164
165Note: The kernel does swapin-readahead and read multiple swaps at once.
166This means swapped-in pages may contain pages for other tasks than a task
167causing page fault. So, we avoid accounting at swap-in I/O.
125 168
126At page migration, accounting information is kept. 169At page migration, accounting information is kept.
127 170
128Note: we just account pages-on-lru because our purpose is to control amount 171Note: we just account pages-on-LRU because our purpose is to control amount
129of used pages. not-on-lru pages are tend to be out-of-control from vm view. 172of used pages; not-on-LRU pages tend to be out-of-control from VM view.
130 173
1312.3 Shared Page Accounting 1742.3 Shared Page Accounting
132 175
@@ -143,6 +186,7 @@ caller of swapoff rather than the users of shmem.
143 186
144 187
1452.4 Swap Extension (CONFIG_CGROUP_MEM_RES_CTLR_SWAP) 1882.4 Swap Extension (CONFIG_CGROUP_MEM_RES_CTLR_SWAP)
189
146Swap Extension allows you to record charge for swap. A swapped-in page is 190Swap Extension allows you to record charge for swap. A swapped-in page is
147charged back to original page allocator if possible. 191charged back to original page allocator if possible.
148 192
@@ -150,13 +194,20 @@ When swap is accounted, following files are added.
150 - memory.memsw.usage_in_bytes. 194 - memory.memsw.usage_in_bytes.
151 - memory.memsw.limit_in_bytes. 195 - memory.memsw.limit_in_bytes.
152 196
153usage of mem+swap is limited by memsw.limit_in_bytes. 197memsw means memory+swap. Usage of memory+swap is limited by
198memsw.limit_in_bytes.
154 199
155* why 'mem+swap' rather than swap. 200Example: Assume a system with 4G of swap. A task which allocates 6G of memory
201(by mistake) under 2G memory limitation will use all swap.
202In this case, setting memsw.limit_in_bytes=3G will prevent bad use of swap.
203By using memsw limit, you can avoid system OOM which can be caused by swap
204shortage.
205
206* why 'memory+swap' rather than swap.
156The global LRU(kswapd) can swap out arbitrary pages. Swap-out means 207The global LRU(kswapd) can swap out arbitrary pages. Swap-out means
157to move account from memory to swap...there is no change in usage of 208to move account from memory to swap...there is no change in usage of
158mem+swap. In other words, when we want to limit the usage of swap without 209memory+swap. In other words, when we want to limit the usage of swap without
159affecting global LRU, mem+swap limit is better than just limiting swap from 210affecting global LRU, memory+swap limit is better than just limiting swap from
160OS point of view. 211OS point of view.
161 212
162* What happens when a cgroup hits memory.memsw.limit_in_bytes 213* What happens when a cgroup hits memory.memsw.limit_in_bytes
@@ -168,12 +219,12 @@ it by cgroup.
168 219
1692.5 Reclaim 2202.5 Reclaim
170 221
171Each cgroup maintains a per cgroup LRU that consists of an active 222Each cgroup maintains a per cgroup LRU which has the same structure as
172and inactive list. When a cgroup goes over its limit, we first try 223global VM. When a cgroup goes over its limit, we first try
173to reclaim memory from the cgroup so as to make space for the new 224to reclaim memory from the cgroup so as to make space for the new
174pages that the cgroup has touched. If the reclaim is unsuccessful, 225pages that the cgroup has touched. If the reclaim is unsuccessful,
175an OOM routine is invoked to select and kill the bulkiest task in the 226an OOM routine is invoked to select and kill the bulkiest task in the
176cgroup. 227cgroup. (See 10. OOM Control below.)
177 228
178The reclaim algorithm has not been modified for cgroups, except that 229The reclaim algorithm has not been modified for cgroups, except that
179pages that are selected for reclaiming come from the per cgroup LRU 230pages that are selected for reclaiming come from the per cgroup LRU
@@ -184,13 +235,22 @@ limits on the root cgroup.
184 235
185Note2: When panic_on_oom is set to "2", the whole system will panic. 236Note2: When panic_on_oom is set to "2", the whole system will panic.
186 237
1872. Locking 238When oom event notifier is registered, event will be delivered.
239(See oom_control section)
240
2412.6 Locking
188 242
189The memory controller uses the following hierarchy 243 lock_page_cgroup()/unlock_page_cgroup() should not be called under
244 mapping->tree_lock.
190 245
1911. zone->lru_lock is used for selecting pages to be isolated 246 Other lock order is following:
1922. mem->per_zone->lru_lock protects the per cgroup LRU (per zone) 247 PG_locked.
1933. lock_page_cgroup() is used to protect page->page_cgroup 248 mm->page_table_lock
249 zone->lru_lock
250 lock_page_cgroup.
251 In many cases, just lock_page_cgroup() is called.
252 per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by
253 zone->lru_lock, it has no lock of its own.
194 254
1953. User Interface 2553. User Interface
196 256
@@ -199,6 +259,7 @@ The memory controller uses the following hierarchy
199a. Enable CONFIG_CGROUPS 259a. Enable CONFIG_CGROUPS
200b. Enable CONFIG_RESOURCE_COUNTERS 260b. Enable CONFIG_RESOURCE_COUNTERS
201c. Enable CONFIG_CGROUP_MEM_RES_CTLR 261c. Enable CONFIG_CGROUP_MEM_RES_CTLR
262d. Enable CONFIG_CGROUP_MEM_RES_CTLR_SWAP (to use swap extension)
202 263
2031. Prepare the cgroups 2641. Prepare the cgroups
204# mkdir -p /cgroups 265# mkdir -p /cgroups
@@ -206,31 +267,28 @@ c. Enable CONFIG_CGROUP_MEM_RES_CTLR
206 267
2072. Make the new group and move bash into it 2682. Make the new group and move bash into it
208# mkdir /cgroups/0 269# mkdir /cgroups/0
209# echo $$ > /cgroups/0/tasks 270# echo $$ > /cgroups/0/tasks
210 271
211Since now we're in the 0 cgroup, 272Since now we're in the 0 cgroup, we can alter the memory limit:
212We can alter the memory limit:
213# echo 4M > /cgroups/0/memory.limit_in_bytes 273# echo 4M > /cgroups/0/memory.limit_in_bytes
214 274
215NOTE: We can use a suffix (k, K, m, M, g or G) to indicate values in kilo, 275NOTE: We can use a suffix (k, K, m, M, g or G) to indicate values in kilo,
216mega or gigabytes. 276mega or gigabytes. (Here, Kilo, Mega, Giga are Kibibytes, Mebibytes, Gibibytes.)
277
217NOTE: We can write "-1" to reset the *.limit_in_bytes(unlimited). 278NOTE: We can write "-1" to reset the *.limit_in_bytes(unlimited).
218NOTE: We cannot set limits on the root cgroup any more. 279NOTE: We cannot set limits on the root cgroup any more.
219 280
220# cat /cgroups/0/memory.limit_in_bytes 281# cat /cgroups/0/memory.limit_in_bytes
2214194304 2824194304
222 283
223NOTE: The interface has now changed to display the usage in bytes
224instead of pages
225
226We can check the usage: 284We can check the usage:
227# cat /cgroups/0/memory.usage_in_bytes 285# cat /cgroups/0/memory.usage_in_bytes
2281216512 2861216512
229 287
230A successful write to this file does not guarantee a successful set of 288A successful write to this file does not guarantee a successful set of
231this limit to the value written into the file. This can be due to a 289this limit to the value written into the file. This can be due to a
232number of factors, such as rounding up to page boundaries or the total 290number of factors, such as rounding up to page boundaries or the total
233availability of memory on the system. The user is required to re-read 291availability of memory on the system. The user is required to re-read
234this file after a write to guarantee the value committed by the kernel. 292this file after a write to guarantee the value committed by the kernel.
235 293
236# echo 1 > memory.limit_in_bytes 294# echo 1 > memory.limit_in_bytes
@@ -245,15 +303,23 @@ caches, RSS and Active pages/Inactive pages are shown.
245 303
2464. Testing 3044. Testing
247 305
248Balbir posted lmbench, AIM9, LTP and vmmstress results [10] and [11]. 306For testing features and implementation, see memcg_test.txt.
249Apart from that v6 has been tested with several applications and regular 307
250daily use. The controller has also been tested on the PPC64, x86_64 and 308Performance test is also important. To see pure memory controller's overhead,
251UML platforms. 309testing on tmpfs will give you good numbers of small overheads.
310Example: do kernel make on tmpfs.
311
312Page-fault scalability is also important. At measuring parallel
313page fault test, multi-process test may be better than multi-thread
314test because it has noise of shared objects/status.
315
316But the above two are testing extreme situations.
317Trying usual test under memory controller is always helpful.
252 318
2534.1 Troubleshooting 3194.1 Troubleshooting
254 320
255Sometimes a user might find that the application under a cgroup is 321Sometimes a user might find that the application under a cgroup is
256terminated. There are several causes for this: 322terminated by OOM killer. There are several causes for this:
257 323
2581. The cgroup limit is too low (just too low to do anything useful) 3241. The cgroup limit is too low (just too low to do anything useful)
2592. The user is using anonymous memory and swap is turned off or too low 3252. The user is using anonymous memory and swap is turned off or too low
@@ -261,6 +327,9 @@ terminated. There are several causes for this:
261A sync followed by echo 1 > /proc/sys/vm/drop_caches will help get rid of 327A sync followed by echo 1 > /proc/sys/vm/drop_caches will help get rid of
262some of the pages cached in the cgroup (page cache pages). 328some of the pages cached in the cgroup (page cache pages).
263 329
330To know what happens, disable OOM_Kill by 10. OOM Control(see below) and
331seeing what happens will be helpful.
332
2644.2 Task migration 3334.2 Task migration
265 334
266When a task migrates from one cgroup to another, its charge is not 335When a task migrates from one cgroup to another, its charge is not
@@ -268,16 +337,19 @@ carried forward by default. The pages allocated from the original cgroup still
268remain charged to it, the charge is dropped when the page is freed or 337remain charged to it, the charge is dropped when the page is freed or
269reclaimed. 338reclaimed.
270 339
271Note: You can move charges of a task along with task migration. See 8. 340You can move charges of a task along with task migration.
341See 8. "Move charges at task migration"
272 342
2734.3 Removing a cgroup 3434.3 Removing a cgroup
274 344
275A cgroup can be removed by rmdir, but as discussed in sections 4.1 and 4.2, a 345A cgroup can be removed by rmdir, but as discussed in sections 4.1 and 4.2, a
276cgroup might have some charge associated with it, even though all 346cgroup might have some charge associated with it, even though all
277tasks have migrated away from it. 347tasks have migrated away from it. (because we charge against pages, not
278Such charges are freed(at default) or moved to its parent. When moved, 348against tasks.)
279both of RSS and CACHES are moved to parent. 349
280If both of them are busy, rmdir() returns -EBUSY. See 5.1 Also. 350Such charges are freed or moved to their parent. At moving, both of RSS
351and CACHES are moved to parent.
352rmdir() may return -EBUSY if freeing/moving fails. See 5.1 also.
281 353
282Charges recorded in swap information is not updated at removal of cgroup. 354Charges recorded in swap information is not updated at removal of cgroup.
283Recorded information is discarded and a cgroup which uses swap (swapcache) 355Recorded information is discarded and a cgroup which uses swap (swapcache)
@@ -293,10 +365,10 @@ will be charged as a new owner of it.
293 365
294 # echo 0 > memory.force_empty 366 # echo 0 > memory.force_empty
295 367
296 Almost all pages tracked by this memcg will be unmapped and freed. Some of 368 Almost all pages tracked by this memory cgroup will be unmapped and freed.
297 pages cannot be freed because it's locked or in-use. Such pages are moved 369 Some pages cannot be freed because they are locked or in-use. Such pages are
298 to parent and this cgroup will be empty. But this may return -EBUSY in 370 moved to parent and this cgroup will be empty. This may return -EBUSY if
299 some too busy case. 371 VM is too busy to free/move all pages immediately.
300 372
301 Typical use case of this interface is that calling this before rmdir(). 373 Typical use case of this interface is that calling this before rmdir().
302 Because rmdir() moves all pages to parent, some out-of-use page caches can be 374 Because rmdir() moves all pages to parent, some out-of-use page caches can be
@@ -306,19 +378,41 @@ will be charged as a new owner of it.
306 378
307memory.stat file includes following statistics 379memory.stat file includes following statistics
308 380
381# per-memory cgroup local status
309cache - # of bytes of page cache memory. 382cache - # of bytes of page cache memory.
310rss - # of bytes of anonymous and swap cache memory. 383rss - # of bytes of anonymous and swap cache memory.
384mapped_file - # of bytes of mapped file (includes tmpfs/shmem)
311pgpgin - # of pages paged in (equivalent to # of charging events). 385pgpgin - # of pages paged in (equivalent to # of charging events).
312pgpgout - # of pages paged out (equivalent to # of uncharging events). 386pgpgout - # of pages paged out (equivalent to # of uncharging events).
313active_anon - # of bytes of anonymous and swap cache memory on active 387swap - # of bytes of swap usage
314 lru list.
315inactive_anon - # of bytes of anonymous memory and swap cache memory on 388inactive_anon - # of bytes of anonymous memory and swap cache memory on
316 inactive lru list. 389 LRU list.
317active_file - # of bytes of file-backed memory on active lru list. 390active_anon - # of bytes of anonymous and swap cache memory on active
318inactive_file - # of bytes of file-backed memory on inactive lru list. 391 inactive LRU list.
392inactive_file - # of bytes of file-backed memory on inactive LRU list.
393active_file - # of bytes of file-backed memory on active LRU list.
319unevictable - # of bytes of memory that cannot be reclaimed (mlocked etc). 394unevictable - # of bytes of memory that cannot be reclaimed (mlocked etc).
320 395
321The following additional stats are dependent on CONFIG_DEBUG_VM. 396# status considering hierarchy (see memory.use_hierarchy settings)
397
398hierarchical_memory_limit - # of bytes of memory limit with regard to hierarchy
399 under which the memory cgroup is
400hierarchical_memsw_limit - # of bytes of memory+swap limit with regard to
401 hierarchy under which memory cgroup is.
402
403total_cache - sum of all children's "cache"
404total_rss - sum of all children's "rss"
405total_mapped_file - sum of all children's "cache"
406total_pgpgin - sum of all children's "pgpgin"
407total_pgpgout - sum of all children's "pgpgout"
408total_swap - sum of all children's "swap"
409total_inactive_anon - sum of all children's "inactive_anon"
410total_active_anon - sum of all children's "active_anon"
411total_inactive_file - sum of all children's "inactive_file"
412total_active_file - sum of all children's "active_file"
413total_unevictable - sum of all children's "unevictable"
414
415# The following additional stats are dependent on CONFIG_DEBUG_VM.
322 416
323inactive_ratio - VM internal parameter. (see mm/page_alloc.c) 417inactive_ratio - VM internal parameter. (see mm/page_alloc.c)
324recent_rotated_anon - VM internal parameter. (see mm/vmscan.c) 418recent_rotated_anon - VM internal parameter. (see mm/vmscan.c)
@@ -327,24 +421,37 @@ recent_scanned_anon - VM internal parameter. (see mm/vmscan.c)
327recent_scanned_file - VM internal parameter. (see mm/vmscan.c) 421recent_scanned_file - VM internal parameter. (see mm/vmscan.c)
328 422
329Memo: 423Memo:
330 recent_rotated means recent frequency of lru rotation. 424 recent_rotated means recent frequency of LRU rotation.
331 recent_scanned means recent # of scans to lru. 425 recent_scanned means recent # of scans to LRU.
332 showing for better debug please see the code for meanings. 426 showing for better debug please see the code for meanings.
333 427
334Note: 428Note:
335 Only anonymous and swap cache memory is listed as part of 'rss' stat. 429 Only anonymous and swap cache memory is listed as part of 'rss' stat.
336 This should not be confused with the true 'resident set size' or the 430 This should not be confused with the true 'resident set size' or the
337 amount of physical memory used by the cgroup. Per-cgroup rss 431 amount of physical memory used by the cgroup.
338 accounting is not done yet. 432 'rss + file_mapped" will give you resident set size of cgroup.
433 (Note: file and shmem may be shared among other cgroups. In that case,
434 file_mapped is accounted only when the memory cgroup is owner of page
435 cache.)
339 436
3405.3 swappiness 4375.3 swappiness
341 Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.
342 438
343 Following cgroups' swappiness can't be changed. 439Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.
344 - root cgroup (uses /proc/sys/vm/swappiness).
345 - a cgroup which uses hierarchy and it has child cgroup.
346 - a cgroup which uses hierarchy and not the root of hierarchy.
347 440
441Following cgroups' swappiness can't be changed.
442- root cgroup (uses /proc/sys/vm/swappiness).
443- a cgroup which uses hierarchy and it has other cgroup(s) below it.
444- a cgroup which uses hierarchy and not the root of hierarchy.
445
4465.4 failcnt
447
448A memory cgroup provides memory.failcnt and memory.memsw.failcnt files.
449This failcnt(== failure count) shows the number of times that a usage counter
450hit its limit. When a memory cgroup hits a limit, failcnt increases and
451memory under it will be reclaimed.
452
453You can reset failcnt by writing 0 to failcnt file.
454# echo 0 > .../memory.failcnt
348 455
3496. Hierarchy support 4566. Hierarchy support
350 457
@@ -363,13 +470,13 @@ hierarchy
363 470
364In the diagram above, with hierarchical accounting enabled, all memory 471In the diagram above, with hierarchical accounting enabled, all memory
365usage of e, is accounted to its ancestors up until the root (i.e, c and root), 472usage of e, is accounted to its ancestors up until the root (i.e, c and root),
366that has memory.use_hierarchy enabled. If one of the ancestors goes over its 473that has memory.use_hierarchy enabled. If one of the ancestors goes over its
367limit, the reclaim algorithm reclaims from the tasks in the ancestor and the 474limit, the reclaim algorithm reclaims from the tasks in the ancestor and the
368children of the ancestor. 475children of the ancestor.
369 476
3706.1 Enabling hierarchical accounting and reclaim 4776.1 Enabling hierarchical accounting and reclaim
371 478
372The memory controller by default disables the hierarchy feature. Support 479A memory cgroup by default disables the hierarchy feature. Support
373can be enabled by writing 1 to memory.use_hierarchy file of the root cgroup 480can be enabled by writing 1 to memory.use_hierarchy file of the root cgroup
374 481
375# echo 1 > memory.use_hierarchy 482# echo 1 > memory.use_hierarchy
@@ -379,10 +486,10 @@ The feature can be disabled by
379# echo 0 > memory.use_hierarchy 486# echo 0 > memory.use_hierarchy
380 487
381NOTE1: Enabling/disabling will fail if the cgroup already has other 488NOTE1: Enabling/disabling will fail if the cgroup already has other
382cgroups created below it. 489 cgroups created below it.
383 490
384NOTE2: When panic_on_oom is set to "2", the whole system will panic in 491NOTE2: When panic_on_oom is set to "2", the whole system will panic in
385case of an oom event in any cgroup. 492 case of an OOM event in any cgroup.
386 493
3877. Soft limits 4947. Soft limits
388 495
@@ -392,7 +499,7 @@ is to allow control groups to use as much of the memory as needed, provided
392a. There is no memory contention 499a. There is no memory contention
393b. They do not exceed their hard limit 500b. They do not exceed their hard limit
394 501
395When the system detects memory contention or low memory control groups 502When the system detects memory contention or low memory, control groups
396are pushed back to their soft limits. If the soft limit of each control 503are pushed back to their soft limits. If the soft limit of each control
397group is very high, they are pushed back as much as possible to make 504group is very high, they are pushed back as much as possible to make
398sure that one control group does not starve the others of memory. 505sure that one control group does not starve the others of memory.
@@ -406,7 +513,7 @@ it gets invoked from balance_pgdat (kswapd).
4067.1 Interface 5137.1 Interface
407 514
408Soft limits can be setup by using the following commands (in this example we 515Soft limits can be setup by using the following commands (in this example we
409assume a soft limit of 256 megabytes) 516assume a soft limit of 256 MiB)
410 517
411# echo 256M > memory.soft_limit_in_bytes 518# echo 256M > memory.soft_limit_in_bytes
412 519
@@ -442,7 +549,7 @@ Note: Charges are moved only when you move mm->owner, IOW, a leader of a thread
442Note: If we cannot find enough space for the task in the destination cgroup, we 549Note: If we cannot find enough space for the task in the destination cgroup, we
443 try to make space by reclaiming memory. Task migration may fail if we 550 try to make space by reclaiming memory. Task migration may fail if we
444 cannot make enough space. 551 cannot make enough space.
445Note: It can take several seconds if you move charges in giga bytes order. 552Note: It can take several seconds if you move charges much.
446 553
447And if you want disable it again: 554And if you want disable it again:
448 555
@@ -451,21 +558,27 @@ And if you want disable it again:
4518.2 Type of charges which can be move 5588.2 Type of charges which can be move
452 559
453Each bits of move_charge_at_immigrate has its own meaning about what type of 560Each bits of move_charge_at_immigrate has its own meaning about what type of
454charges should be moved. 561charges should be moved. But in any cases, it must be noted that an account of
562a page or a swap can be moved only when it is charged to the task's current(old)
563memory cgroup.
455 564
456 bit | what type of charges would be moved ? 565 bit | what type of charges would be moved ?
457 -----+------------------------------------------------------------------------ 566 -----+------------------------------------------------------------------------
458 0 | A charge of an anonymous page(or swap of it) used by the target task. 567 0 | A charge of an anonymous page(or swap of it) used by the target task.
459 | Those pages and swaps must be used only by the target task. You must 568 | Those pages and swaps must be used only by the target task. You must
460 | enable Swap Extension(see 2.4) to enable move of swap charges. 569 | enable Swap Extension(see 2.4) to enable move of swap charges.
461 570 -----+------------------------------------------------------------------------
462Note: Those pages and swaps must be charged to the old cgroup. 571 1 | A charge of file pages(normal file, tmpfs file(e.g. ipc shared memory)
463Note: More type of pages(e.g. file cache, shmem,) will be supported by other 572 | and swaps of tmpfs file) mmapped by the target task. Unlike the case of
464 bits in future. 573 | anonymous pages, file pages(and swaps) in the range mmapped by the task
574 | will be moved even if the task hasn't done page fault, i.e. they might
575 | not be the task's "RSS", but other task's "RSS" that maps the same file.
576 | And mapcount of the page is ignored(the page can be moved even if
577 | page_mapcount(page) > 1). You must enable Swap Extension(see 2.4) to
578 | enable move of swap charges.
465 579
4668.3 TODO 5808.3 TODO
467 581
468- Add support for other types of pages(e.g. file cache, shmem, etc.).
469- Implement madvise(2) to let users decide the vma to be moved or not to be 582- Implement madvise(2) to let users decide the vma to be moved or not to be
470 moved. 583 moved.
471- All of moving charge operations are done under cgroup_mutex. It's not good 584- All of moving charge operations are done under cgroup_mutex. It's not good
@@ -473,22 +586,61 @@ Note: More type of pages(e.g. file cache, shmem,) will be supported by other
473 586
4749. Memory thresholds 5879. Memory thresholds
475 588
476Memory controler implements memory thresholds using cgroups notification 589Memory cgroup implements memory thresholds using cgroups notification
477API (see cgroups.txt). It allows to register multiple memory and memsw 590API (see cgroups.txt). It allows to register multiple memory and memsw
478thresholds and gets notifications when it crosses. 591thresholds and gets notifications when it crosses.
479 592
480To register a threshold application need: 593To register a threshold application need:
481 - create an eventfd using eventfd(2); 594- create an eventfd using eventfd(2);
482 - open memory.usage_in_bytes or memory.memsw.usage_in_bytes; 595- open memory.usage_in_bytes or memory.memsw.usage_in_bytes;
483 - write string like "<event_fd> <memory.usage_in_bytes> <threshold>" to 596- write string like "<event_fd> <fd of memory.usage_in_bytes> <threshold>" to
484 cgroup.event_control. 597 cgroup.event_control.
485 598
486Application will be notified through eventfd when memory usage crosses 599Application will be notified through eventfd when memory usage crosses
487threshold in any direction. 600threshold in any direction.
488 601
489It's applicable for root and non-root cgroup. 602It's applicable for root and non-root cgroup.
490 603
49110. TODO 60410. OOM Control
605
606memory.oom_control file is for OOM notification and other controls.
607
608Memory cgroup implements OOM notifier using cgroup notification
609API (See cgroups.txt). It allows to register multiple OOM notification
610delivery and gets notification when OOM happens.
611
612To register a notifier, application need:
613 - create an eventfd using eventfd(2)
614 - open memory.oom_control file
615 - write string like "<event_fd> <fd of memory.oom_control>" to
616 cgroup.event_control
617
618Application will be notified through eventfd when OOM happens.
619OOM notification doesn't work for root cgroup.
620
621You can disable OOM-killer by writing "1" to memory.oom_control file, as:
622
623 #echo 1 > memory.oom_control
624
625This operation is only allowed to the top cgroup of sub-hierarchy.
626If OOM-killer is disabled, tasks under cgroup will hang/sleep
627in memory cgroup's OOM-waitqueue when they request accountable memory.
628
629For running them, you have to relax the memory cgroup's OOM status by
630 * enlarge limit or reduce usage.
631To reduce usage,
632 * kill some tasks.
633 * move some tasks to other group with account migration.
634 * remove some files (on tmpfs?)
635
636Then, stopped tasks will work again.
637
638At reading, current status of OOM is shown.
639 oom_kill_disable 0 or 1 (if 1, oom-killer is disabled)
640 under_oom 0 or 1 (if 1, the memory cgroup is under OOM, tasks may
641 be stopped.)
642
64311. TODO
492 644
4931. Add support for accounting huge pages (as a separate controller) 6451. Add support for accounting huge pages (as a separate controller)
4942. Make per-cgroup scanner reclaim not-shared pages first 6462. Make per-cgroup scanner reclaim not-shared pages first
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index a86152ae2f6f..672be0109d02 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -646,3 +646,13 @@ Who: Thomas Gleixner <tglx@linutronix.de>
646 646
647---------------------------- 647----------------------------
648 648
649What: old ieee1394 subsystem (CONFIG_IEEE1394)
650When: 2.6.37
651Files: drivers/ieee1394/ except init_ohci1394_dma.c
652Why: superseded by drivers/firewire/ (CONFIG_FIREWIRE) which offers more
653 features, better performance, and better security, all with smaller
654 and more modern code base
655Who: Stefan Richter <stefanr@s5r6.in-berlin.de>
656
657----------------------------
658
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index af1608070cd5..96d4293607ec 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -380,7 +380,7 @@ prototypes:
380 int (*open) (struct inode *, struct file *); 380 int (*open) (struct inode *, struct file *);
381 int (*flush) (struct file *); 381 int (*flush) (struct file *);
382 int (*release) (struct inode *, struct file *); 382 int (*release) (struct inode *, struct file *);
383 int (*fsync) (struct file *, struct dentry *, int datasync); 383 int (*fsync) (struct file *, int datasync);
384 int (*aio_fsync) (struct kiocb *, int datasync); 384 int (*aio_fsync) (struct kiocb *, int datasync);
385 int (*fasync) (int, struct file *, int); 385 int (*fasync) (int, struct file *, int);
386 int (*lock) (struct file *, int, struct file_lock *); 386 int (*lock) (struct file *, int, struct file_lock *);
@@ -429,8 +429,9 @@ check_flags: no
429implementations. If your fs is not using generic_file_llseek, you 429implementations. If your fs is not using generic_file_llseek, you
430need to acquire and release the appropriate locks in your ->llseek(). 430need to acquire and release the appropriate locks in your ->llseek().
431For many filesystems, it is probably safe to acquire the inode 431For many filesystems, it is probably safe to acquire the inode
432mutex. Note some filesystems (i.e. remote ones) provide no 432mutex or just to use i_size_read() instead.
433protection for i_size so you will need to use the BKL. 433Note: this does not protect the file->f_pos against concurrent modifications
434since this is something the userspace has to take care about.
434 435
435Note: ext2_release() was *the* source of contention on fs-intensive 436Note: ext2_release() was *the* source of contention on fs-intensive
436loads and dropping BKL on ->release() helps to get rid of that (we still 437loads and dropping BKL on ->release() helps to get rid of that (we still
diff --git a/Documentation/filesystems/squashfs.txt b/Documentation/filesystems/squashfs.txt
index b324c033035a..203f7202cc9e 100644
--- a/Documentation/filesystems/squashfs.txt
+++ b/Documentation/filesystems/squashfs.txt
@@ -38,7 +38,8 @@ Hard link support: yes no
38Real inode numbers: yes no 38Real inode numbers: yes no
3932-bit uids/gids: yes no 3932-bit uids/gids: yes no
40File creation time: yes no 40File creation time: yes no
41Xattr and ACL support: no no 41Xattr support: yes no
42ACL support: no no
42 43
43Squashfs compresses data, inodes and directories. In addition, inode and 44Squashfs compresses data, inodes and directories. In addition, inode and
44directory data are highly compacted, and packed on byte boundaries. Each 45directory data are highly compacted, and packed on byte boundaries. Each
@@ -58,7 +59,7 @@ obtained from this site also.
583. SQUASHFS FILESYSTEM DESIGN 593. SQUASHFS FILESYSTEM DESIGN
59----------------------------- 60-----------------------------
60 61
61A squashfs filesystem consists of seven parts, packed together on a byte 62A squashfs filesystem consists of a maximum of eight parts, packed together on a byte
62alignment: 63alignment:
63 64
64 --------------- 65 ---------------
@@ -80,6 +81,9 @@ alignment:
80 |---------------| 81 |---------------|
81 | uid/gid | 82 | uid/gid |
82 | lookup table | 83 | lookup table |
84 |---------------|
85 | xattr |
86 | table |
83 --------------- 87 ---------------
84 88
85Compressed data blocks are written to the filesystem as files are read from 89Compressed data blocks are written to the filesystem as files are read from
@@ -192,6 +196,26 @@ This table is stored compressed into metadata blocks. A second index table is
192used to locate these. This second index table for speed of access (and because 196used to locate these. This second index table for speed of access (and because
193it is small) is read at mount time and cached in memory. 197it is small) is read at mount time and cached in memory.
194 198
1993.7 Xattr table
200---------------
201
202The xattr table contains extended attributes for each inode. The xattrs
203for each inode are stored in a list, each list entry containing a type,
204name and value field. The type field encodes the xattr prefix
205("user.", "trusted." etc) and it also encodes how the name/value fields
206should be interpreted. Currently the type indicates whether the value
207is stored inline (in which case the value field contains the xattr value),
208or if it is stored out of line (in which case the value field stores a
209reference to where the actual value is stored). This allows large values
210to be stored out of line improving scanning and lookup performance and it
211also allows values to be de-duplicated, the value being stored once, and
212all other occurences holding an out of line reference to that value.
213
214The xattr lists are packed into compressed 8K metadata blocks.
215To reduce overhead in inodes, rather than storing the on-disk
216location of the xattr list inside each inode, a 32-bit xattr id
217is stored. This xattr id is mapped into the location of the xattr
218list using a second xattr id lookup table.
195 219
1964. TODOS AND OUTSTANDING ISSUES 2204. TODOS AND OUTSTANDING ISSUES
197------------------------------- 221-------------------------------
@@ -199,9 +223,7 @@ it is small) is read at mount time and cached in memory.
1994.1 Todo list 2234.1 Todo list
200------------- 224-------------
201 225
202Implement Xattr and ACL support. The Squashfs 4.0 filesystem layout has hooks 226Implement ACL support.
203for these but the code has not been written. Once the code has been written
204the existing layout should not require modification.
205 227
2064.2 Squashfs internal cache 2284.2 Squashfs internal cache
207--------------------------- 229---------------------------
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index b66858538df5..94677e7dcb13 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -401,11 +401,16 @@ otherwise noted.
401 started might not be in the page cache at the end of the 401 started might not be in the page cache at the end of the
402 walk). 402 walk).
403 403
404 truncate: called by the VFS to change the size of a file. The 404 truncate: Deprecated. This will not be called if ->setsize is defined.
405 Called by the VFS to change the size of a file. The
405 i_size field of the inode is set to the desired size by the 406 i_size field of the inode is set to the desired size by the
406 VFS before this method is called. This method is called by 407 VFS before this method is called. This method is called by
407 the truncate(2) system call and related functionality. 408 the truncate(2) system call and related functionality.
408 409
410 Note: ->truncate and vmtruncate are deprecated. Do not add new
411 instances/calls of these. Filesystems should be converted to do their
412 truncate sequence via ->setattr().
413
409 permission: called by the VFS to check for access rights on a POSIX-like 414 permission: called by the VFS to check for access rights on a POSIX-like
410 filesystem. 415 filesystem.
411 416
@@ -729,7 +734,7 @@ struct file_operations {
729 int (*open) (struct inode *, struct file *); 734 int (*open) (struct inode *, struct file *);
730 int (*flush) (struct file *); 735 int (*flush) (struct file *);
731 int (*release) (struct inode *, struct file *); 736 int (*release) (struct inode *, struct file *);
732 int (*fsync) (struct file *, struct dentry *, int datasync); 737 int (*fsync) (struct file *, int datasync);
733 int (*aio_fsync) (struct kiocb *, int datasync); 738 int (*aio_fsync) (struct kiocb *, int datasync);
734 int (*fasync) (int, struct file *, int); 739 int (*fasync) (int, struct file *, int);
735 int (*lock) (struct file *, int, struct file_lock *); 740 int (*lock) (struct file *, int, struct file_lock *);
diff --git a/Documentation/hwmon/dme1737 b/Documentation/hwmon/dme1737
index 001d2e70bc11..fc5df7654d63 100644
--- a/Documentation/hwmon/dme1737
+++ b/Documentation/hwmon/dme1737
@@ -9,11 +9,15 @@ Supported chips:
9 * SMSC SCH3112, SCH3114, SCH3116 9 * SMSC SCH3112, SCH3114, SCH3116
10 Prefix: 'sch311x' 10 Prefix: 'sch311x'
11 Addresses scanned: none, address read from Super-I/O config space 11 Addresses scanned: none, address read from Super-I/O config space
12 Datasheet: http://www.nuhorizons.com/FeaturedProducts/Volume1/SMSC/311x.pdf 12 Datasheet: Available on the Internet
13 * SMSC SCH5027 13 * SMSC SCH5027
14 Prefix: 'sch5027' 14 Prefix: 'sch5027'
15 Addresses scanned: I2C 0x2c, 0x2d, 0x2e 15 Addresses scanned: I2C 0x2c, 0x2d, 0x2e
16 Datasheet: Provided by SMSC upon request and under NDA 16 Datasheet: Provided by SMSC upon request and under NDA
17 * SMSC SCH5127
18 Prefix: 'sch5127'
19 Addresses scanned: none, address read from Super-I/O config space
20 Datasheet: Provided by SMSC upon request and under NDA
17 21
18Authors: 22Authors:
19 Juerg Haefliger <juergh@gmail.com> 23 Juerg Haefliger <juergh@gmail.com>
@@ -36,8 +40,8 @@ Description
36----------- 40-----------
37 41
38This driver implements support for the hardware monitoring capabilities of the 42This driver implements support for the hardware monitoring capabilities of the
39SMSC DME1737 and Asus A8000 (which are the same), SMSC SCH5027, and SMSC 43SMSC DME1737 and Asus A8000 (which are the same), SMSC SCH5027, SCH311x,
40SCH311x Super-I/O chips. These chips feature monitoring of 3 temp sensors 44and SCH5127 Super-I/O chips. These chips feature monitoring of 3 temp sensors
41temp[1-3] (2 remote diodes and 1 internal), 7 voltages in[0-6] (6 external and 45temp[1-3] (2 remote diodes and 1 internal), 7 voltages in[0-6] (6 external and
421 internal) and up to 6 fan speeds fan[1-6]. Additionally, the chips implement 461 internal) and up to 6 fan speeds fan[1-6]. Additionally, the chips implement
43up to 5 PWM outputs pwm[1-3,5-6] for controlling fan speeds both manually and 47up to 5 PWM outputs pwm[1-3,5-6] for controlling fan speeds both manually and
@@ -48,14 +52,14 @@ Fan[3-6] and pwm[3,5-6] are optional features and their availability depends on
48the configuration of the chip. The driver will detect which features are 52the configuration of the chip. The driver will detect which features are
49present during initialization and create the sysfs attributes accordingly. 53present during initialization and create the sysfs attributes accordingly.
50 54
51For the SCH311x, fan[1-3] and pwm[1-3] are always present and fan[4-6] and 55For the SCH311x and SCH5127, fan[1-3] and pwm[1-3] are always present and
52pwm[5-6] don't exist. 56fan[4-6] and pwm[5-6] don't exist.
53 57
54The hardware monitoring features of the DME1737, A8000, and SCH5027 are only 58The hardware monitoring features of the DME1737, A8000, and SCH5027 are only
55accessible via SMBus, while the SCH311x only provides access via the ISA bus. 59accessible via SMBus, while the SCH311x and SCH5127 only provide access via
56The driver will therefore register itself as an I2C client driver if it detects 60the ISA bus. The driver will therefore register itself as an I2C client driver
57a DME1737, A8000, or SCH5027 and as a platform driver if it detects a SCH311x 61if it detects a DME1737, A8000, or SCH5027 and as a platform driver if it
58chip. 62detects a SCH311x or SCH5127 chip.
59 63
60 64
61Voltage Monitoring 65Voltage Monitoring
@@ -76,7 +80,7 @@ DME1737, A8000:
76 in6: Vbat (+3.0V) 0V - 4.38V 80 in6: Vbat (+3.0V) 0V - 4.38V
77 81
78SCH311x: 82SCH311x:
79 in0: +2.5V 0V - 6.64V 83 in0: +2.5V 0V - 3.32V
80 in1: Vccp (processor core) 0V - 2V 84 in1: Vccp (processor core) 0V - 2V
81 in2: VCC (internal +3.3V) 0V - 4.38V 85 in2: VCC (internal +3.3V) 0V - 4.38V
82 in3: +5V 0V - 6.64V 86 in3: +5V 0V - 6.64V
@@ -93,6 +97,15 @@ SCH5027:
93 in5: VTR (+3.3V standby) 0V - 4.38V 97 in5: VTR (+3.3V standby) 0V - 4.38V
94 in6: Vbat (+3.0V) 0V - 4.38V 98 in6: Vbat (+3.0V) 0V - 4.38V
95 99
100SCH5127:
101 in0: +2.5 0V - 3.32V
102 in1: Vccp (processor core) 0V - 3V
103 in2: VCC (internal +3.3V) 0V - 4.38V
104 in3: V2_IN 0V - 1.5V
105 in4: V1_IN 0V - 1.5V
106 in5: VTR (+3.3V standby) 0V - 4.38V
107 in6: Vbat (+3.0V) 0V - 4.38V
108
96Each voltage input has associated min and max limits which trigger an alarm 109Each voltage input has associated min and max limits which trigger an alarm
97when crossed. 110when crossed.
98 111
@@ -293,3 +306,21 @@ pwm[1-3]_auto_point1_pwm RW Auto PWM pwm point. Auto_point1 is the
293pwm[1-3]_auto_point2_pwm RO Auto PWM pwm point. Auto_point2 is the 306pwm[1-3]_auto_point2_pwm RO Auto PWM pwm point. Auto_point2 is the
294 full-speed duty-cycle which is hard- 307 full-speed duty-cycle which is hard-
295 wired to 255 (100% duty-cycle). 308 wired to 255 (100% duty-cycle).
309
310Chip Differences
311----------------
312
313Feature dme1737 sch311x sch5027 sch5127
314-------------------------------------------------------
315temp[1-3]_offset yes yes
316vid yes
317zone3 yes yes yes
318zone[1-3]_hyst yes yes
319pwm min/off yes yes
320fan3 opt yes opt yes
321pwm3 opt yes opt yes
322fan4 opt opt
323fan5 opt opt
324pwm5 opt opt
325fan6 opt opt
326pwm6 opt opt
diff --git a/Documentation/hwmon/lm63 b/Documentation/hwmon/lm63
index 31660bf97979..b9843eab1afb 100644
--- a/Documentation/hwmon/lm63
+++ b/Documentation/hwmon/lm63
@@ -7,6 +7,11 @@ Supported chips:
7 Addresses scanned: I2C 0x4c 7 Addresses scanned: I2C 0x4c
8 Datasheet: Publicly available at the National Semiconductor website 8 Datasheet: Publicly available at the National Semiconductor website
9 http://www.national.com/pf/LM/LM63.html 9 http://www.national.com/pf/LM/LM63.html
10 * National Semiconductor LM64
11 Prefix: 'lm64'
12 Addresses scanned: I2C 0x18 and 0x4e
13 Datasheet: Publicly available at the National Semiconductor website
14 http://www.national.com/pf/LM/LM64.html
10 15
11Author: Jean Delvare <khali@linux-fr.org> 16Author: Jean Delvare <khali@linux-fr.org>
12 17
@@ -55,3 +60,5 @@ The lm63 driver will not update its values more frequently than every
55second; reading them more often will do no harm, but will return 'old' 60second; reading them more often will do no harm, but will return 'old'
56values. 61values.
57 62
63The LM64 is effectively an LM63 with GPIO lines. The driver does not
64support these GPIO lines at present.
diff --git a/Documentation/hwmon/ltc4245 b/Documentation/hwmon/ltc4245
index 02838a47d862..86b5880d8502 100644
--- a/Documentation/hwmon/ltc4245
+++ b/Documentation/hwmon/ltc4245
@@ -72,9 +72,7 @@ in6_min_alarm 5v output undervoltage alarm
72in7_min_alarm 3v output undervoltage alarm 72in7_min_alarm 3v output undervoltage alarm
73in8_min_alarm Vee (-12v) output undervoltage alarm 73in8_min_alarm Vee (-12v) output undervoltage alarm
74 74
75in9_input GPIO #1 voltage data 75in9_input GPIO voltage data
76in10_input GPIO #2 voltage data
77in11_input GPIO #3 voltage data
78 76
79power1_input 12v power usage (mW) 77power1_input 12v power usage (mW)
80power2_input 5v power usage (mW) 78power2_input 5v power usage (mW)
diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface
index 3de6b0bcb147..d4e2917c6f18 100644
--- a/Documentation/hwmon/sysfs-interface
+++ b/Documentation/hwmon/sysfs-interface
@@ -80,9 +80,9 @@ All entries (except name) are optional, and should only be created in a
80given driver if the chip has the feature. 80given driver if the chip has the feature.
81 81
82 82
83******** 83*********************
84* Name * 84* Global attributes *
85******** 85*********************
86 86
87name The chip name. 87name The chip name.
88 This should be a short, lowercase string, not containing 88 This should be a short, lowercase string, not containing
@@ -91,6 +91,13 @@ 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
94update_rate The rate at which the chip will update readings.
95 Unit: millisecond
96 RW
97 Some devices have a variable update rate. This attribute
98 can be used to change the update rate to the desired
99 frequency.
100
94 101
95************ 102************
96* Voltages * 103* Voltages *
diff --git a/Documentation/hwmon/tmp102 b/Documentation/hwmon/tmp102
new file mode 100644
index 000000000000..8454a7763122
--- /dev/null
+++ b/Documentation/hwmon/tmp102
@@ -0,0 +1,26 @@
1Kernel driver tmp102
2====================
3
4Supported chips:
5 * Texas Instruments TMP102
6 Prefix: 'tmp102'
7 Addresses scanned: none
8 Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp102.html
9
10Author:
11 Steven King <sfking@fdwdc.com>
12
13Description
14-----------
15
16The Texas Instruments TMP102 implements one temperature sensor. Limits can be
17set through the Overtemperature Shutdown register and Hysteresis register. The
18sensor is accurate to 0.5 degree over the range of -25 to +85 C, and to 1.0
19degree from -40 to +125 C. Resolution of the sensor is 0.0625 degree. The
20operating temperature has a minimum of -55 C and a maximum of +150 C.
21
22The TMP102 has a programmable update rate that can select between 8, 4, 1, and
230.5 Hz. (Currently the driver only supports the default of 4 Hz).
24
25The driver provides the common sysfs-interface for temperatures (see
26Documentation/hwmon/sysfs-interface under Temperatures).
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index b56ea860da21..1808f1157f30 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -145,11 +145,10 @@ and is between 256 and 4096 characters. It is defined in the file
145 145
146 acpi= [HW,ACPI,X86] 146 acpi= [HW,ACPI,X86]
147 Advanced Configuration and Power Interface 147 Advanced Configuration and Power Interface
148 Format: { force | off | ht | strict | noirq | rsdt } 148 Format: { force | off | strict | noirq | rsdt }
149 force -- enable ACPI if default was off 149 force -- enable ACPI if default was off
150 off -- disable ACPI if default was on 150 off -- disable ACPI if default was on
151 noirq -- do not use ACPI for IRQ routing 151 noirq -- do not use ACPI for IRQ routing
152 ht -- run only enough ACPI to enable Hyper Threading
153 strict -- Be less tolerant of platforms that are not 152 strict -- Be less tolerant of platforms that are not
154 strictly ACPI specification compliant. 153 strictly ACPI specification compliant.
155 rsdt -- prefer RSDT over (default) XSDT 154 rsdt -- prefer RSDT over (default) XSDT
@@ -758,6 +757,10 @@ and is between 256 and 4096 characters. It is defined in the file
758 Default value is 0. 757 Default value is 0.
759 Value can be changed at runtime via /selinux/enforce. 758 Value can be changed at runtime via /selinux/enforce.
760 759
760 erst_disable [ACPI]
761 Disable Error Record Serialization Table (ERST)
762 support.
763
761 ether= [HW,NET] Ethernet cards parameters 764 ether= [HW,NET] Ethernet cards parameters
762 This option is obsoleted by the "netdev=" option, which 765 This option is obsoleted by the "netdev=" option, which
763 has equivalent usage. See its documentation for details. 766 has equivalent usage. See its documentation for details.
@@ -852,6 +855,11 @@ and is between 256 and 4096 characters. It is defined in the file
852 hd= [EIDE] (E)IDE hard drive subsystem geometry 855 hd= [EIDE] (E)IDE hard drive subsystem geometry
853 Format: <cyl>,<head>,<sect> 856 Format: <cyl>,<head>,<sect>
854 857
858 hest_disable [ACPI]
859 Disable Hardware Error Source Table (HEST) support;
860 corresponding firmware-first mode error processing
861 logic will be disabled.
862
855 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact 863 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
856 size of <nn>. This works even on boxes that have no 864 size of <nn>. This works even on boxes that have no
857 highmem otherwise. This also works to reduce highmem 865 highmem otherwise. This also works to reduce highmem
@@ -1252,6 +1260,8 @@ and is between 256 and 4096 characters. It is defined in the file
1252 * nohrst, nosrst, norst: suppress hard, soft 1260 * nohrst, nosrst, norst: suppress hard, soft
1253 and both resets. 1261 and both resets.
1254 1262
1263 * dump_id: dump IDENTIFY data.
1264
1255 If there are multiple matching configurations changing 1265 If there are multiple matching configurations changing
1256 the same attribute, the last one is used. 1266 the same attribute, the last one is used.
1257 1267
diff --git a/Documentation/vm/numa b/Documentation/vm/numa
index e93ad9425e2a..a200a386429d 100644
--- a/Documentation/vm/numa
+++ b/Documentation/vm/numa
@@ -1,41 +1,149 @@
1Started Nov 1999 by Kanoj Sarcar <kanoj@sgi.com> 1Started Nov 1999 by Kanoj Sarcar <kanoj@sgi.com>
2 2
3The intent of this file is to have an uptodate, running commentary 3What is NUMA?
4from different people about NUMA specific code in the Linux vm. 4
5 5This question can be answered from a couple of perspectives: the
6What is NUMA? It is an architecture where the memory access times 6hardware view and the Linux software view.
7for different regions of memory from a given processor varies 7
8according to the "distance" of the memory region from the processor. 8From the hardware perspective, a NUMA system is a computer platform that
9Each region of memory to which access times are the same from any 9comprises multiple components or assemblies each of which may contain 0
10cpu, is called a node. On such architectures, it is beneficial if 10or more CPUs, local memory, and/or IO buses. For brevity and to
11the kernel tries to minimize inter node communications. Schemes 11disambiguate the hardware view of these physical components/assemblies
12for this range from kernel text and read-only data replication 12from the software abstraction thereof, we'll call the components/assemblies
13across nodes, and trying to house all the data structures that 13'cells' in this document.
14key components of the kernel need on memory on that node. 14
15 15Each of the 'cells' may be viewed as an SMP [symmetric multi-processor] subset
16Currently, all the numa support is to provide efficient handling 16of the system--although some components necessary for a stand-alone SMP system
17of widely discontiguous physical memory, so architectures which 17may not be populated on any given cell. The cells of the NUMA system are
18are not NUMA but can have huge holes in the physical address space 18connected together with some sort of system interconnect--e.g., a crossbar or
19can use the same code. All this code is bracketed by CONFIG_DISCONTIGMEM. 19point-to-point link are common types of NUMA system interconnects. Both of
20 20these types of interconnects can be aggregated to create NUMA platforms with
21The initial port includes NUMAizing the bootmem allocator code by 21cells at multiple distances from other cells.
22encapsulating all the pieces of information into a bootmem_data_t 22
23structure. Node specific calls have been added to the allocator. 23For Linux, the NUMA platforms of interest are primarily what is known as Cache
24In theory, any platform which uses the bootmem allocator should 24Coherent NUMA or ccNUMA systems. With ccNUMA systems, all memory is visible
25be able to put the bootmem and mem_map data structures anywhere 25to and accessible from any CPU attached to any cell and cache coherency
26it deems best. 26is handled in hardware by the processor caches and/or the system interconnect.
27 27
28Each node's page allocation data structures have also been encapsulated 28Memory access time and effective memory bandwidth varies depending on how far
29into a pg_data_t. The bootmem_data_t is just one part of this. To 29away the cell containing the CPU or IO bus making the memory access is from the
30make the code look uniform between NUMA and regular UMA platforms, 30cell containing the target memory. For example, access to memory by CPUs
31UMA platforms have a statically allocated pg_data_t too (contig_page_data). 31attached to the same cell will experience faster access times and higher
32For the sake of uniformity, the function num_online_nodes() is also defined 32bandwidths than accesses to memory on other, remote cells. NUMA platforms
33for all platforms. As we run benchmarks, we might decide to NUMAize 33can have cells at multiple remote distances from any given cell.
34more variables like low_on_memory, nr_free_pages etc into the pg_data_t. 34
35 35Platform vendors don't build NUMA systems just to make software developers'
36The NUMA aware page allocation code currently tries to allocate pages 36lives interesting. Rather, this architecture is a means to provide scalable
37from different nodes in a round robin manner. This will be changed to 37memory bandwidth. However, to achieve scalable memory bandwidth, system and
38do concentratic circle search, starting from current node, once the 38application software must arrange for a large majority of the memory references
39NUMA port achieves more maturity. The call alloc_pages_node has been 39[cache misses] to be to "local" memory--memory on the same cell, if any--or
40added, so that drivers can make the call and not worry about whether 40to the closest cell with memory.
41it is running on a NUMA or UMA platform. 41
42This leads to the Linux software view of a NUMA system:
43
44Linux divides the system's hardware resources into multiple software
45abstractions called "nodes". Linux maps the nodes onto the physical cells
46of the hardware platform, abstracting away some of the details for some
47architectures. As with physical cells, software nodes may contain 0 or more
48CPUs, memory and/or IO buses. And, again, memory accesses to memory on
49"closer" nodes--nodes that map to closer cells--will generally experience
50faster access times and higher effective bandwidth than accesses to more
51remote cells.
52
53For some architectures, such as x86, Linux will "hide" any node representing a
54physical cell that has no memory attached, and reassign any CPUs attached to
55that cell to a node representing a cell that does have memory. Thus, on
56these architectures, one cannot assume that all CPUs that Linux associates with
57a given node will see the same local memory access times and bandwidth.
58
59In addition, for some architectures, again x86 is an example, Linux supports
60the emulation of additional nodes. For NUMA emulation, linux will carve up
61the existing nodes--or the system memory for non-NUMA platforms--into multiple
62nodes. Each emulated node will manage a fraction of the underlying cells'
63physical memory. NUMA emluation is useful for testing NUMA kernel and
64application features on non-NUMA platforms, and as a sort of memory resource
65management mechanism when used together with cpusets.
66[see Documentation/cgroups/cpusets.txt]
67
68For each node with memory, Linux constructs an independent memory management
69subsystem, complete with its own free page lists, in-use page lists, usage
70statistics and locks to mediate access. In addition, Linux constructs for
71each memory zone [one or more of DMA, DMA32, NORMAL, HIGH_MEMORY, MOVABLE],
72an ordered "zonelist". A zonelist specifies the zones/nodes to visit when a
73selected zone/node cannot satisfy the allocation request. This situation,
74when a zone has no available memory to satisfy a request, is called
75"overflow" or "fallback".
76
77Because some nodes contain multiple zones containing different types of
78memory, Linux must decide whether to order the zonelists such that allocations
79fall back to the same zone type on a different node, or to a different zone
80type on the same node. This is an important consideration because some zones,
81such as DMA or DMA32, represent relatively scarce resources. Linux chooses
82a default zonelist order based on the sizes of the various zone types relative
83to the total memory of the node and the total memory of the system. The
84default zonelist order may be overridden using the numa_zonelist_order kernel
85boot parameter or sysctl. [see Documentation/kernel-parameters.txt and
86Documentation/sysctl/vm.txt]
87
88By default, Linux will attempt to satisfy memory allocation requests from the
89node to which the CPU that executes the request is assigned. Specifically,
90Linux will attempt to allocate from the first node in the appropriate zonelist
91for the node where the request originates. This is called "local allocation."
92If the "local" node cannot satisfy the request, the kernel will examine other
93nodes' zones in the selected zonelist looking for the first zone in the list
94that can satisfy the request.
95
96Local allocation will tend to keep subsequent access to the allocated memory
97"local" to the underlying physical resources and off the system interconnect--
98as long as the task on whose behalf the kernel allocated some memory does not
99later migrate away from that memory. The Linux scheduler is aware of the
100NUMA topology of the platform--embodied in the "scheduling domains" data
101structures [see Documentation/scheduler/sched-domains.txt]--and the scheduler
102attempts to minimize task migration to distant scheduling domains. However,
103the scheduler does not take a task's NUMA footprint into account directly.
104Thus, under sufficient imbalance, tasks can migrate between nodes, remote
105from their initial node and kernel data structures.
106
107System administrators and application designers can restrict a task's migration
108to improve NUMA locality using various CPU affinity command line interfaces,
109such as taskset(1) and numactl(1), and program interfaces such as
110sched_setaffinity(2). Further, one can modify the kernel's default local
111allocation behavior using Linux NUMA memory policy.
112[see Documentation/vm/numa_memory_policy.]
113
114System administrators can restrict the CPUs and nodes' memories that a non-
115privileged user can specify in the scheduling or NUMA commands and functions
116using control groups and CPUsets. [see Documentation/cgroups/CPUsets.txt]
117
118On architectures that do not hide memoryless nodes, Linux will include only
119zones [nodes] with memory in the zonelists. This means that for a memoryless
120node the "local memory node"--the node of the first zone in CPU's node's
121zonelist--will not be the node itself. Rather, it will be the node that the
122kernel selected as the nearest node with memory when it built the zonelists.
123So, default, local allocations will succeed with the kernel supplying the
124closest available memory. This is a consequence of the same mechanism that
125allows such allocations to fallback to other nearby nodes when a node that
126does contain memory overflows.
127
128Some kernel allocations do not want or cannot tolerate this allocation fallback
129behavior. Rather they want to be sure they get memory from the specified node
130or get notified that the node has no free memory. This is usually the case when
131a subsystem allocates per CPU memory resources, for example.
132
133A typical model for making such an allocation is to obtain the node id of the
134node to which the "current CPU" is attached using one of the kernel's
135numa_node_id() or CPU_to_node() functions and then request memory from only
136the node id returned. When such an allocation fails, the requesting subsystem
137may revert to its own fallback path. The slab kernel memory allocator is an
138example of this. Or, the subsystem may choose to disable or not to enable
139itself on allocation failure. The kernel profiling subsystem is an example of
140this.
141
142If the architecture supports--does not hide--memoryless nodes, then CPUs
143attached to memoryless nodes would always incur the fallback path overhead
144or some subsystems would fail to initialize if they attempted to allocated
145memory exclusively from a node without memory. To support such
146architectures transparently, kernel subsystems can use the numa_mem_id()
147or cpu_to_mem() function to locate the "local memory node" for the calling or
148specified CPU. Again, this is the same node from which default, local page
149allocations will be attempted.