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authorIngo Molnar <mingo@elte.hu>2009-02-22 14:05:19 -0500
committerIngo Molnar <mingo@elte.hu>2009-02-22 14:05:19 -0500
commitfc6fc7f1b1095b92d4834e69b385b91e412a7ce5 (patch)
tree2ad451d5dac4d460830536944cef1de93be36b2a /Documentation
parentef1f87aa7ba6224bef1b750b3272ba281d8f43ed (diff)
parent770824bdc421ff58a64db608294323571c949f4c (diff)
Merge branch 'linus' into x86/apic
Conflicts: arch/x86/mach-default/setup.c Semantic conflict resolution: arch/x86/kernel/setup.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-firmware-memmap2
-rw-r--r--Documentation/PCI/PCIEBUS-HOWTO.txt2
-rw-r--r--Documentation/cgroups/cgroups.txt6
-rw-r--r--Documentation/cgroups/cpusets.txt65
-rw-r--r--Documentation/driver-model/device.txt8
-rw-r--r--Documentation/filesystems/sysfs.txt50
-rw-r--r--Documentation/hwmon/hpfall.c101
-rw-r--r--Documentation/hwmon/lis3lv02d8
-rw-r--r--Documentation/tracers/mmiotrace.txt6
9 files changed, 185 insertions, 63 deletions
diff --git a/Documentation/ABI/testing/sysfs-firmware-memmap b/Documentation/ABI/testing/sysfs-firmware-memmap
index 0d99ee6ae02..eca0d65087d 100644
--- a/Documentation/ABI/testing/sysfs-firmware-memmap
+++ b/Documentation/ABI/testing/sysfs-firmware-memmap
@@ -1,6 +1,6 @@
1What: /sys/firmware/memmap/ 1What: /sys/firmware/memmap/
2Date: June 2008 2Date: June 2008
3Contact: Bernhard Walle <bwalle@suse.de> 3Contact: Bernhard Walle <bernhard.walle@gmx.de>
4Description: 4Description:
5 On all platforms, the firmware provides a memory map which the 5 On all platforms, the firmware provides a memory map which the
6 kernel reads. The resources from that memory map are registered 6 kernel reads. The resources from that memory map are registered
diff --git a/Documentation/PCI/PCIEBUS-HOWTO.txt b/Documentation/PCI/PCIEBUS-HOWTO.txt
index 9a07e38631b..6bd5f372ade 100644
--- a/Documentation/PCI/PCIEBUS-HOWTO.txt
+++ b/Documentation/PCI/PCIEBUS-HOWTO.txt
@@ -93,7 +93,7 @@ the PCI Express Port Bus driver from loading a service driver.
93 93
94int pcie_port_service_register(struct pcie_port_service_driver *new) 94int pcie_port_service_register(struct pcie_port_service_driver *new)
95 95
96This API replaces the Linux Driver Model's pci_module_init API. A 96This API replaces the Linux Driver Model's pci_register_driver API. A
97service driver should always calls pcie_port_service_register at 97service driver should always calls pcie_port_service_register at
98module init. Note that after service driver being loaded, calls 98module init. Note that after service driver being loaded, calls
99such as pci_enable_device(dev) and pci_set_master(dev) are no longer 99such as pci_enable_device(dev) and pci_set_master(dev) are no longer
diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
index d9e5d6f41b9..93feb844448 100644
--- a/Documentation/cgroups/cgroups.txt
+++ b/Documentation/cgroups/cgroups.txt
@@ -252,10 +252,8 @@ cgroup file system directories.
252When a task is moved from one cgroup to another, it gets a new 252When a task is moved from one cgroup to another, it gets a new
253css_set pointer - if there's an already existing css_set with the 253css_set pointer - if there's an already existing css_set with the
254desired collection of cgroups then that group is reused, else a new 254desired collection of cgroups then that group is reused, else a new
255css_set is allocated. Note that the current implementation uses a 255css_set is allocated. The appropriate existing css_set is located by
256linear search to locate an appropriate existing css_set, so isn't 256looking into a hash table.
257very efficient. A future version will use a hash table for better
258performance.
259 257
260To allow access from a cgroup to the css_sets (and hence tasks) 258To allow access from a cgroup to the css_sets (and hence tasks)
261that comprise it, a set of cg_cgroup_link objects form a lattice; 259that comprise it, a set of cg_cgroup_link objects form a lattice;
diff --git a/Documentation/cgroups/cpusets.txt b/Documentation/cgroups/cpusets.txt
index 5c86c258c79..0611e9528c7 100644
--- a/Documentation/cgroups/cpusets.txt
+++ b/Documentation/cgroups/cpusets.txt
@@ -142,7 +142,7 @@ into the rest of the kernel, none in performance critical paths:
142 - in fork and exit, to attach and detach a task from its cpuset. 142 - in fork and exit, to attach and detach a task from its cpuset.
143 - in sched_setaffinity, to mask the requested CPUs by what's 143 - in sched_setaffinity, to mask the requested CPUs by what's
144 allowed in that tasks cpuset. 144 allowed in that tasks cpuset.
145 - in sched.c migrate_all_tasks(), to keep migrating tasks within 145 - in sched.c migrate_live_tasks(), to keep migrating tasks within
146 the CPUs allowed by their cpuset, if possible. 146 the CPUs allowed by their cpuset, if possible.
147 - in the mbind and set_mempolicy system calls, to mask the requested 147 - in the mbind and set_mempolicy system calls, to mask the requested
148 Memory Nodes by what's allowed in that tasks cpuset. 148 Memory Nodes by what's allowed in that tasks cpuset.
@@ -175,6 +175,10 @@ files describing that cpuset:
175 - mem_exclusive flag: is memory placement exclusive? 175 - mem_exclusive flag: is memory placement exclusive?
176 - mem_hardwall flag: is memory allocation hardwalled 176 - mem_hardwall flag: is memory allocation hardwalled
177 - memory_pressure: measure of how much paging pressure in cpuset 177 - memory_pressure: measure of how much paging pressure in cpuset
178 - memory_spread_page flag: if set, spread page cache evenly on allowed nodes
179 - memory_spread_slab flag: if set, spread slab cache evenly on allowed nodes
180 - sched_load_balance flag: if set, load balance within CPUs on that cpuset
181 - sched_relax_domain_level: the searching range when migrating tasks
178 182
179In addition, the root cpuset only has the following file: 183In addition, the root cpuset only has the following file:
180 - memory_pressure_enabled flag: compute memory_pressure? 184 - memory_pressure_enabled flag: compute memory_pressure?
@@ -252,7 +256,7 @@ is causing.
252 256
253This is useful both on tightly managed systems running a wide mix of 257This is useful both on tightly managed systems running a wide mix of
254submitted jobs, which may choose to terminate or re-prioritize jobs that 258submitted jobs, which may choose to terminate or re-prioritize jobs that
255are trying to use more memory than allowed on the nodes assigned them, 259are trying to use more memory than allowed on the nodes assigned to them,
256and with tightly coupled, long running, massively parallel scientific 260and with tightly coupled, long running, massively parallel scientific
257computing jobs that will dramatically fail to meet required performance 261computing jobs that will dramatically fail to meet required performance
258goals if they start to use more memory than allowed to them. 262goals if they start to use more memory than allowed to them.
@@ -378,7 +382,7 @@ as cpusets and sched_setaffinity.
378The algorithmic cost of load balancing and its impact on key shared 382The algorithmic cost of load balancing and its impact on key shared
379kernel data structures such as the task list increases more than 383kernel data structures such as the task list increases more than
380linearly with the number of CPUs being balanced. So the scheduler 384linearly with the number of CPUs being balanced. So the scheduler
381has support to partition the systems CPUs into a number of sched 385has support to partition the systems CPUs into a number of sched
382domains such that it only load balances within each sched domain. 386domains such that it only load balances within each sched domain.
383Each sched domain covers some subset of the CPUs in the system; 387Each sched domain covers some subset of the CPUs in the system;
384no two sched domains overlap; some CPUs might not be in any sched 388no two sched domains overlap; some CPUs might not be in any sched
@@ -485,17 +489,22 @@ of CPUs allowed to a cpuset having 'sched_load_balance' enabled.
485The internal kernel cpuset to scheduler interface passes from the 489The internal kernel cpuset to scheduler interface passes from the
486cpuset code to the scheduler code a partition of the load balanced 490cpuset code to the scheduler code a partition of the load balanced
487CPUs in the system. This partition is a set of subsets (represented 491CPUs in the system. This partition is a set of subsets (represented
488as an array of cpumask_t) of CPUs, pairwise disjoint, that cover all 492as an array of struct cpumask) of CPUs, pairwise disjoint, that cover
489the CPUs that must be load balanced. 493all the CPUs that must be load balanced.
490 494
491Whenever the 'sched_load_balance' flag changes, or CPUs come or go 495The cpuset code builds a new such partition and passes it to the
492from a cpuset with this flag enabled, or a cpuset with this flag 496scheduler sched domain setup code, to have the sched domains rebuilt
493enabled is removed, the cpuset code builds a new such partition and 497as necessary, whenever:
494passes it to the scheduler sched domain setup code, to have the sched 498 - the 'sched_load_balance' flag of a cpuset with non-empty CPUs changes,
495domains rebuilt as necessary. 499 - or CPUs come or go from a cpuset with this flag enabled,
500 - or 'sched_relax_domain_level' value of a cpuset with non-empty CPUs
501 and with this flag enabled changes,
502 - or a cpuset with non-empty CPUs and with this flag enabled is removed,
503 - or a cpu is offlined/onlined.
496 504
497This partition exactly defines what sched domains the scheduler should 505This partition exactly defines what sched domains the scheduler should
498setup - one sched domain for each element (cpumask_t) in the partition. 506setup - one sched domain for each element (struct cpumask) in the
507partition.
499 508
500The scheduler remembers the currently active sched domain partitions. 509The scheduler remembers the currently active sched domain partitions.
501When the scheduler routine partition_sched_domains() is invoked from 510When the scheduler routine partition_sched_domains() is invoked from
@@ -559,7 +568,7 @@ domain, the largest value among those is used. Be careful, if one
559requests 0 and others are -1 then 0 is used. 568requests 0 and others are -1 then 0 is used.
560 569
561Note that modifying this file will have both good and bad effects, 570Note that modifying this file will have both good and bad effects,
562and whether it is acceptable or not will be depend on your situation. 571and whether it is acceptable or not depends on your situation.
563Don't modify this file if you are not sure. 572Don't modify this file if you are not sure.
564 573
565If your situation is: 574If your situation is:
@@ -600,19 +609,15 @@ to allocate a page of memory for that task.
600 609
601If a cpuset has its 'cpus' modified, then each task in that cpuset 610If a cpuset has its 'cpus' modified, then each task in that cpuset
602will have its allowed CPU placement changed immediately. Similarly, 611will have its allowed CPU placement changed immediately. Similarly,
603if a tasks pid is written to a cpusets 'tasks' file, in either its 612if a tasks pid is written to another cpusets 'tasks' file, then its
604current cpuset or another cpuset, then its allowed CPU placement is 613allowed CPU placement is changed immediately. If such a task had been
605changed immediately. If such a task had been bound to some subset 614bound to some subset of its cpuset using the sched_setaffinity() call,
606of its cpuset using the sched_setaffinity() call, the task will be 615the task will be allowed to run on any CPU allowed in its new cpuset,
607allowed to run on any CPU allowed in its new cpuset, negating the 616negating the effect of the prior sched_setaffinity() call.
608affect of the prior sched_setaffinity() call.
609 617
610In summary, the memory placement of a task whose cpuset is changed is 618In summary, the memory placement of a task whose cpuset is changed is
611updated by the kernel, on the next allocation of a page for that task, 619updated by the kernel, on the next allocation of a page for that task,
612but the processor placement is not updated, until that tasks pid is 620and the processor placement is updated immediately.
613rewritten to the 'tasks' file of its cpuset. This is done to avoid
614impacting the scheduler code in the kernel with a check for changes
615in a tasks processor placement.
616 621
617Normally, once a page is allocated (given a physical page 622Normally, once a page is allocated (given a physical page
618of main memory) then that page stays on whatever node it 623of main memory) then that page stays on whatever node it
@@ -681,10 +686,14 @@ and then start a subshell 'sh' in that cpuset:
681 # The next line should display '/Charlie' 686 # The next line should display '/Charlie'
682 cat /proc/self/cpuset 687 cat /proc/self/cpuset
683 688
684In the future, a C library interface to cpusets will likely be 689There are ways to query or modify cpusets:
685available. For now, the only way to query or modify cpusets is 690 - via the cpuset file system directly, using the various cd, mkdir, echo,
686via the cpuset file system, using the various cd, mkdir, echo, cat, 691 cat, rmdir commands from the shell, or their equivalent from C.
687rmdir commands from the shell, or their equivalent from C. 692 - via the C library libcpuset.
693 - via the C library libcgroup.
694 (http://sourceforge.net/proects/libcg/)
695 - via the python application cset.
696 (http://developer.novell.com/wiki/index.php/Cpuset)
688 697
689The sched_setaffinity calls can also be done at the shell prompt using 698The sched_setaffinity calls can also be done at the shell prompt using
690SGI's runon or Robert Love's taskset. The mbind and set_mempolicy 699SGI's runon or Robert Love's taskset. The mbind and set_mempolicy
@@ -756,7 +765,7 @@ mount -t cpuset X /dev/cpuset
756 765
757is equivalent to 766is equivalent to
758 767
759mount -t cgroup -ocpuset X /dev/cpuset 768mount -t cgroup -ocpuset,noprefix X /dev/cpuset
760echo "/sbin/cpuset_release_agent" > /dev/cpuset/release_agent 769echo "/sbin/cpuset_release_agent" > /dev/cpuset/release_agent
761 770
7622.2 Adding/removing cpus 7712.2 Adding/removing cpus
diff --git a/Documentation/driver-model/device.txt b/Documentation/driver-model/device.txt
index a05ec50f800..a7cbfff40d0 100644
--- a/Documentation/driver-model/device.txt
+++ b/Documentation/driver-model/device.txt
@@ -127,9 +127,11 @@ void unlock_device(struct device * dev);
127Attributes 127Attributes
128~~~~~~~~~~ 128~~~~~~~~~~
129struct device_attribute { 129struct device_attribute {
130 struct attribute attr; 130 struct attribute attr;
131 ssize_t (*show)(struct device * dev, char * buf, size_t count, loff_t off); 131 ssize_t (*show)(struct device *dev, struct device_attribute *attr,
132 ssize_t (*store)(struct device * dev, const char * buf, size_t count, loff_t off); 132 char *buf);
133 ssize_t (*store)(struct device *dev, struct device_attribute *attr,
134 const char *buf, size_t count);
133}; 135};
134 136
135Attributes of devices can be exported via drivers using a simple 137Attributes of devices can be exported via drivers using a simple
diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt
index 9e9c348275a..7e81e37c0b1 100644
--- a/Documentation/filesystems/sysfs.txt
+++ b/Documentation/filesystems/sysfs.txt
@@ -2,8 +2,10 @@
2sysfs - _The_ filesystem for exporting kernel objects. 2sysfs - _The_ filesystem for exporting kernel objects.
3 3
4Patrick Mochel <mochel@osdl.org> 4Patrick Mochel <mochel@osdl.org>
5Mike Murphy <mamurph@cs.clemson.edu>
5 6
610 January 2003 7Revised: 22 February 2009
8Original: 10 January 2003
7 9
8 10
9What it is: 11What it is:
@@ -64,12 +66,13 @@ An attribute definition is simply:
64 66
65struct attribute { 67struct attribute {
66 char * name; 68 char * name;
69 struct module *owner;
67 mode_t mode; 70 mode_t mode;
68}; 71};
69 72
70 73
71int sysfs_create_file(struct kobject * kobj, struct attribute * attr); 74int sysfs_create_file(struct kobject * kobj, const struct attribute * attr);
72void sysfs_remove_file(struct kobject * kobj, struct attribute * attr); 75void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr);
73 76
74 77
75A bare attribute contains no means to read or write the value of the 78A bare attribute contains no means to read or write the value of the
@@ -80,9 +83,11 @@ a specific object type.
80For example, the driver model defines struct device_attribute like: 83For example, the driver model defines struct device_attribute like:
81 84
82struct device_attribute { 85struct device_attribute {
83 struct attribute attr; 86 struct attribute attr;
84 ssize_t (*show)(struct device * dev, char * buf); 87 ssize_t (*show)(struct device *dev, struct device_attribute *attr,
85 ssize_t (*store)(struct device * dev, const char * buf); 88 char *buf);
89 ssize_t (*store)(struct device *dev, struct device_attribute *attr,
90 const char *buf, size_t count);
86}; 91};
87 92
88int device_create_file(struct device *, struct device_attribute *); 93int device_create_file(struct device *, struct device_attribute *);
@@ -90,12 +95,8 @@ void device_remove_file(struct device *, struct device_attribute *);
90 95
91It also defines this helper for defining device attributes: 96It also defines this helper for defining device attributes:
92 97
93#define DEVICE_ATTR(_name, _mode, _show, _store) \ 98#define DEVICE_ATTR(_name, _mode, _show, _store) \
94struct device_attribute dev_attr_##_name = { \ 99struct device_attribute dev_attr_##_name = __ATTR(_name, _mode, _show, _store)
95 .attr = {.name = __stringify(_name) , .mode = _mode }, \
96 .show = _show, \
97 .store = _store, \
98};
99 100
100For example, declaring 101For example, declaring
101 102
@@ -107,9 +108,9 @@ static struct device_attribute dev_attr_foo = {
107 .attr = { 108 .attr = {
108 .name = "foo", 109 .name = "foo",
109 .mode = S_IWUSR | S_IRUGO, 110 .mode = S_IWUSR | S_IRUGO,
111 .show = show_foo,
112 .store = store_foo,
110 }, 113 },
111 .show = show_foo,
112 .store = store_foo,
113}; 114};
114 115
115 116
@@ -161,10 +162,12 @@ To read or write attributes, show() or store() methods must be
161specified when declaring the attribute. The method types should be as 162specified when declaring the attribute. The method types should be as
162simple as those defined for device attributes: 163simple as those defined for device attributes:
163 164
164 ssize_t (*show)(struct device * dev, char * buf); 165ssize_t (*show)(struct device * dev, struct device_attribute * attr,
165 ssize_t (*store)(struct device * dev, const char * buf); 166 char * buf);
167ssize_t (*store)(struct device * dev, struct device_attribute * attr,
168 const char * buf);
166 169
167IOW, they should take only an object and a buffer as parameters. 170IOW, they should take only an object, an attribute, and a buffer as parameters.
168 171
169 172
170sysfs allocates a buffer of size (PAGE_SIZE) and passes it to the 173sysfs allocates a buffer of size (PAGE_SIZE) and passes it to the
@@ -299,14 +302,16 @@ The following interface layers currently exist in sysfs:
299Structure: 302Structure:
300 303
301struct device_attribute { 304struct device_attribute {
302 struct attribute attr; 305 struct attribute attr;
303 ssize_t (*show)(struct device * dev, char * buf); 306 ssize_t (*show)(struct device *dev, struct device_attribute *attr,
304 ssize_t (*store)(struct device * dev, const char * buf); 307 char *buf);
308 ssize_t (*store)(struct device *dev, struct device_attribute *attr,
309 const char *buf, size_t count);
305}; 310};
306 311
307Declaring: 312Declaring:
308 313
309DEVICE_ATTR(_name, _str, _mode, _show, _store); 314DEVICE_ATTR(_name, _mode, _show, _store);
310 315
311Creation/Removal: 316Creation/Removal:
312 317
@@ -342,7 +347,8 @@ Structure:
342struct driver_attribute { 347struct driver_attribute {
343 struct attribute attr; 348 struct attribute attr;
344 ssize_t (*show)(struct device_driver *, char * buf); 349 ssize_t (*show)(struct device_driver *, char * buf);
345 ssize_t (*store)(struct device_driver *, const char * buf); 350 ssize_t (*store)(struct device_driver *, const char * buf,
351 size_t count);
346}; 352};
347 353
348Declaring: 354Declaring:
diff --git a/Documentation/hwmon/hpfall.c b/Documentation/hwmon/hpfall.c
new file mode 100644
index 00000000000..bbea1ccfd46
--- /dev/null
+++ b/Documentation/hwmon/hpfall.c
@@ -0,0 +1,101 @@
1/* Disk protection for HP machines.
2 *
3 * Copyright 2008 Eric Piel
4 * Copyright 2009 Pavel Machek <pavel@suse.cz>
5 *
6 * GPLv2.
7 */
8
9#include <stdio.h>
10#include <stdlib.h>
11#include <unistd.h>
12#include <fcntl.h>
13#include <sys/stat.h>
14#include <sys/types.h>
15#include <string.h>
16#include <stdint.h>
17#include <errno.h>
18#include <signal.h>
19
20void write_int(char *path, int i)
21{
22 char buf[1024];
23 int fd = open(path, O_RDWR);
24 if (fd < 0) {
25 perror("open");
26 exit(1);
27 }
28 sprintf(buf, "%d", i);
29 if (write(fd, buf, strlen(buf)) != strlen(buf)) {
30 perror("write");
31 exit(1);
32 }
33 close(fd);
34}
35
36void set_led(int on)
37{
38 write_int("/sys/class/leds/hp::hddprotect/brightness", on);
39}
40
41void protect(int seconds)
42{
43 write_int("/sys/block/sda/device/unload_heads", seconds*1000);
44}
45
46int on_ac(void)
47{
48// /sys/class/power_supply/AC0/online
49}
50
51int lid_open(void)
52{
53// /proc/acpi/button/lid/LID/state
54}
55
56void ignore_me(void)
57{
58 protect(0);
59 set_led(0);
60
61}
62
63int main(int argc, char* argv[])
64{
65 int fd, ret;
66
67 fd = open("/dev/freefall", O_RDONLY);
68 if (fd < 0) {
69 perror("open");
70 return EXIT_FAILURE;
71 }
72
73 signal(SIGALRM, ignore_me);
74
75 for (;;) {
76 unsigned char count;
77
78 ret = read(fd, &count, sizeof(count));
79 alarm(0);
80 if ((ret == -1) && (errno == EINTR)) {
81 /* Alarm expired, time to unpark the heads */
82 continue;
83 }
84
85 if (ret != sizeof(count)) {
86 perror("read");
87 break;
88 }
89
90 protect(21);
91 set_led(1);
92 if (1 || on_ac() || lid_open()) {
93 alarm(2);
94 } else {
95 alarm(20);
96 }
97 }
98
99 close(fd);
100 return EXIT_SUCCESS;
101}
diff --git a/Documentation/hwmon/lis3lv02d b/Documentation/hwmon/lis3lv02d
index 0fcfc4a7ccd..287f8c90265 100644
--- a/Documentation/hwmon/lis3lv02d
+++ b/Documentation/hwmon/lis3lv02d
@@ -33,6 +33,14 @@ rate - reports the sampling rate of the accelerometer device in HZ
33This driver also provides an absolute input class device, allowing 33This driver also provides an absolute input class device, allowing
34the laptop to act as a pinball machine-esque joystick. 34the laptop to act as a pinball machine-esque joystick.
35 35
36Another feature of the driver is misc device called "freefall" that
37acts similar to /dev/rtc and reacts on free-fall interrupts received
38from the device. It supports blocking operations, poll/select and
39fasync operation modes. You must read 1 bytes from the device. The
40result is number of free-fall interrupts since the last successful
41read (or 255 if number of interrupts would not fit).
42
43
36Axes orientation 44Axes orientation
37---------------- 45----------------
38 46
diff --git a/Documentation/tracers/mmiotrace.txt b/Documentation/tracers/mmiotrace.txt
index cde23b4a12a..5731c67abc5 100644
--- a/Documentation/tracers/mmiotrace.txt
+++ b/Documentation/tracers/mmiotrace.txt
@@ -78,12 +78,10 @@ to view your kernel log and look for "mmiotrace has lost events" warning. If
78events were lost, the trace is incomplete. You should enlarge the buffers and 78events were lost, the trace is incomplete. You should enlarge the buffers and
79try again. Buffers are enlarged by first seeing how large the current buffers 79try again. Buffers are enlarged by first seeing how large the current buffers
80are: 80are:
81$ cat /debug/tracing/trace_entries 81$ cat /debug/tracing/buffer_size_kb
82gives you a number. Approximately double this number and write it back, for 82gives you a number. Approximately double this number and write it back, for
83instance: 83instance:
84$ echo 0 > /debug/tracing/tracing_enabled 84$ echo 128000 > /debug/tracing/buffer_size_kb
85$ echo 128000 > /debug/tracing/trace_entries
86$ echo 1 > /debug/tracing/tracing_enabled
87Then start again from the top. 85Then start again from the top.
88 86
89If you are doing a trace for a driver project, e.g. Nouveau, you should also 87If you are doing a trace for a driver project, e.g. Nouveau, you should also