linux/Documentation
Andrew Shewmaker c9b1d0981f mm: limit growth of 3% hardcoded other user reserve
Add user_reserve_kbytes knob.

Limit the growth of the memory reserved for other user processes to
min(3% current process size, user_reserve_pages).  Only about 8MB is
necessary to enable recovery in the default mode, and only a few hundred
MB are required even when overcommit is disabled.

user_reserve_pages defaults to min(3% free pages, 128MB)

I arrived at 128MB by taking the max VSZ of sshd, login, bash, and top ...
then adding the RSS of each.

This only affects OVERCOMMIT_NEVER mode.

Background

1. user reserve

__vm_enough_memory reserves a hardcoded 3% of the current process size for
other applications when overcommit is disabled.  This was done so that a
user could recover if they launched a memory hogging process.  Without the
reserve, a user would easily run into a message such as:

bash: fork: Cannot allocate memory

2. admin reserve

Additionally, a hardcoded 3% of free memory is reserved for root in both
overcommit 'guess' and 'never' modes.  This was intended to prevent a
scenario where root-cant-log-in and perform recovery operations.

Note that this reserve shrinks, and doesn't guarantee a useful reserve.

Motivation

The two hardcoded memory reserves should be updated to account for current
memory sizes.

Also, the admin reserve would be more useful if it didn't shrink too much.

When the current code was originally written, 1GB was considered
"enterprise".  Now the 3% reserve can grow to multiple GB on large memory
systems, and it only needs to be a few hundred MB at most to enable a user
or admin to recover a system with an unwanted memory hogging process.

I've found that reducing these reserves is especially beneficial for a
specific type of application load:

 * single application system
 * one or few processes (e.g. one per core)
 * allocating all available memory
 * not initializing every page immediately
 * long running

I've run scientific clusters with this sort of load.  A long running job
sometimes failed many hours (weeks of CPU time) into a calculation.  They
weren't initializing all of their memory immediately, and they weren't
using calloc, so I put systems into overcommit 'never' mode.  These
clusters run diskless and have no swap.

However, with the current reserves, a user wishing to allocate as much
memory as possible to one process may be prevented from using, for
example, almost 2GB out of 32GB.

The effect is less, but still significant when a user starts a job with
one process per core.  I have repeatedly seen a set of processes
requesting the same amount of memory fail because one of them could not
allocate the amount of memory a user would expect to be able to allocate.
For example, Message Passing Interfce (MPI) processes, one per core.  And
it is similar for other parallel programming frameworks.

Changing this reserve code will make the overcommit never mode more useful
by allowing applications to allocate nearly all of the available memory.

Also, the new admin_reserve_kbytes will be safer than the current behavior
since the hardcoded 3% of available memory reserve can shrink to something
useless in the case where applications have grabbed all available memory.

Risks

* "bash: fork: Cannot allocate memory"

  The downside of the first patch-- which creates a tunable user reserve
  that is only used in overcommit 'never' mode--is that an admin can set
  it so low that a user may not be able to kill their process, even if
  they already have a shell prompt.

  Of course, a user can get in the same predicament with the current 3%
  reserve--they just have to launch processes until 3% becomes negligible.

* root-cant-log-in problem

  The second patch, adding the tunable rootuser_reserve_pages, allows
  the admin to shoot themselves in the foot by setting it too small.  They
  can easily get the system into a state where root-can't-log-in.

  However, the new admin_reserve_kbytes will be safer than the current
  behavior since the hardcoded 3% of available memory reserve can shrink
  to something useless in the case where applications have grabbed all
  available memory.

Alternatives

 * Memory cgroups provide a more flexible way to limit application memory.

   Not everyone wants to set up cgroups or deal with their overhead.

 * We could create a fourth overcommit mode which provides smaller reserves.

   The size of useful reserves may be drastically different depending
   on the whether the system is embedded or enterprise.

 * Force users to initialize all of their memory or use calloc.

   Some users don't want/expect the system to overcommit when they malloc.
   Overcommit 'never' mode is for this scenario, and it should work well.

The new user and admin reserve tunables are simple to use, with low
overhead compared to cgroups.  The patches preserve current behavior where
3% of memory is less than 128MB, except that the admin reserve doesn't
shrink to an unusable size under pressure.  The code allows admins to tune
for embedded and enterprise usage.

FAQ

 * How is the root-cant-login problem addressed?
   What happens if admin_reserve_pages is set to 0?

   Root is free to shoot themselves in the foot by setting
   admin_reserve_kbytes too low.

   On x86_64, the minimum useful reserve is:
     8MB for overcommit 'guess'
   128MB for overcommit 'never'

   admin_reserve_pages defaults to min(3% free memory, 8MB)

   So, anyone switching to 'never' mode needs to adjust
   admin_reserve_pages.

 * How do you calculate a minimum useful reserve?

   A user or the admin needs enough memory to login and perform
   recovery operations, which includes, at a minimum:

   sshd or login + bash (or some other shell) + top (or ps, kill, etc.)

   For overcommit 'guess', we can sum resident set sizes (RSS)
   because we only need enough memory to handle what the recovery
   programs will typically use. On x86_64 this is about 8MB.

   For overcommit 'never', we can take the max of their virtual sizes (VSZ)
   and add the sum of their RSS. We use VSZ instead of RSS because mode
   forces us to ensure we can fulfill all of the requested memory allocations--
   even if the programs only use a fraction of what they ask for.
   On x86_64 this is about 128MB.

   When swap is enabled, reserves are useful even when they are as
   small as 10MB, regardless of overcommit mode.

   When both swap and overcommit are disabled, then the admin should
   tune the reserves higher to be absolutley safe. Over 230MB each
   was safest in my testing.

 * What happens if user_reserve_pages is set to 0?

   Note, this only affects overcomitt 'never' mode.

   Then a user will be able to allocate all available memory minus
   admin_reserve_kbytes.

   However, they will easily see a message such as:

   "bash: fork: Cannot allocate memory"

   And they won't be able to recover/kill their application.
   The admin should be able to recover the system if
   admin_reserve_kbytes is set appropriately.

 * What's the difference between overcommit 'guess' and 'never'?

   "Guess" allows an allocation if there are enough free + reclaimable
   pages. It has a hardcoded 3% of free pages reserved for root.

   "Never" allows an allocation if there is enough swap + a configurable
   percentage (default is 50) of physical RAM. It has a hardcoded 3% of
   free pages reserved for root, like "Guess" mode. It also has a
   hardcoded 3% of the current process size reserved for additional
   applications.

 * Why is overcommit 'guess' not suitable even when an app eventually
   writes to every page? It takes free pages, file pages, available
   swap pages, reclaimable slab pages into consideration. In other words,
   these are all pages available, then why isn't overcommit suitable?

   Because it only looks at the present state of the system. It
   does not take into account the memory that other applications have
   malloced, but haven't initialized yet. It overcommits the system.

Test Summary

There was little change in behavior in the default overcommit 'guess'
mode with swap enabled before and after the patch. This was expected.

Systems run most predictably (i.e. no oom kills) in overcommit 'never'
mode with swap enabled. This also allowed the most memory to be allocated
to a user application.

Overcommit 'guess' mode without swap is a bad idea. It is easy to
crash the system. None of the other tested combinations crashed.
This matches my experience on the Roadrunner supercomputer.

Without the tunable user reserve, a system in overcommit 'never' mode
and without swap does not allow the admin to recover, although the
admin can.

With the new tunable reserves, a system in overcommit 'never' mode
and without swap can be configured to:

1. maximize user-allocatable memory, running close to the edge of
recoverability

2. maximize recoverability, sacrificing allocatable memory to
ensure that a user cannot take down a system

Test Description

Fedora 18 VM - 4 x86_64 cores, 5725MB RAM, 4GB Swap

System is booted into multiuser console mode, with unnecessary services
turned off. Caches were dropped before each test.

Hogs are user memtester processes that attempt to allocate all free memory
as reported by /proc/meminfo

In overcommit 'never' mode, memory_ratio=100

Test Results

3.9.0-rc1-mm1

Overcommit | Swap | Hogs | MB Got/Wanted | OOMs | User Recovery | Admin Recovery
----------   ----   ----   -------------   ----   -------------   --------------
guess        yes    1      5432/5432       no     yes             yes
guess        yes    4      5444/5444       1      yes             yes
guess        no     1      5302/5449       no     yes             yes
guess        no     4      -               crash  no              no

never        yes    1      5460/5460       1      yes             yes
never        yes    4      5460/5460       1      yes             yes
never        no     1      5218/5432       no     no              yes
never        no     4      5203/5448       no     no              yes

3.9.0-rc1-mm1-tunablereserves

User and Admin Recovery show their respective reserves, if applicable.

Overcommit | Swap | Hogs | MB Got/Wanted | OOMs | User Recovery | Admin Recovery
----------   ----   ----   -------------   ----   -------------   --------------
guess        yes    1      5419/5419       no     - yes           8MB yes
guess        yes    4      5436/5436       1      - yes           8MB yes
guess        no     1      5440/5440       *      - yes           8MB yes
guess        no     4      -               crash  - no            8MB no

* process would successfully mlock, then the oom killer would pick it

never        yes    1      5446/5446       no     10MB yes        20MB yes
never        yes    4      5456/5456       no     10MB yes        20MB yes
never        no     1      5387/5429       no     128MB no        8MB barely
never        no     1      5323/5428       no     226MB barely    8MB barely
never        no     1      5323/5428       no     226MB barely    8MB barely

never        no     1      5359/5448       no     10MB no         10MB barely

never        no     1      5323/5428       no     0MB no          10MB barely
never        no     1      5332/5428       no     0MB no          50MB yes
never        no     1      5293/5429       no     0MB no          90MB yes

never        no     1      5001/5427       no     230MB yes       338MB yes
never        no     4*     4998/5424       no     230MB yes       338MB yes

* more memtesters were launched, able to allocate approximately another 100MB

Future Work

 - Test larger memory systems.

 - Test an embedded image.

 - Test other architectures.

 - Time malloc microbenchmarks.

 - Would it be useful to be able to set overcommit policy for
   each memory cgroup?

 - Some lines are slightly above 80 chars.
   Perhaps define a macro to convert between pages and kb?
   Other places in the kernel do this.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: make init_user_reserve() static]
Signed-off-by: Andrew Shewmaker <agshew@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29 15:54:36 -07:00
..
ABI USB patches for 3.10-rc1 2013-04-29 12:19:23 -07:00
accounting doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c 2012-11-26 14:22:21 +01:00
acpi ACPI / Documentation: refer to correct file for acpi_platform_device_ids[] table 2013-02-13 13:43:02 +01:00
aoe aoe: allow user to disable target failure timeout 2012-12-17 17:15:25 -08:00
arm fbdev changes for 3.8: 2012-12-15 13:03:48 -08:00
arm64 arm64: Add simple earlyprintk support 2013-01-22 17:51:01 +00:00
auxdisplay
backlight backlight: lp855x_bl: support new LP8557 device 2013-02-21 17:22:25 -08:00
blackfin Documentation: Fix typo in multiple files in Documentation 2012-04-16 14:37:13 +02:00
block cfq-iosched: enable full blkcg hierarchy support 2013-01-09 08:05:11 -08:00
blockdev nbd: update documentation and link to mailinglist 2013-02-27 19:10:22 -08:00
bus-devices ARM: OMAP2+: gpmc: generic timing calculation 2012-11-09 18:07:11 +05:30
cdrom
cgroups Merge branch 'for-3.9/core' of git://git.kernel.dk/linux-block 2013-02-28 12:52:24 -08:00
connector connector: Move cn_test.c away from NLMSG_PUT(). 2012-06-26 21:19:02 -07:00
console
cpu-freq cpufreq: Update Documentation for cpus and related_cpus 2013-02-02 00:01:16 +01:00
cpuidle Honor state disabling in the cpuidle ladder governor 2012-09-04 01:35:44 +02:00
cris CRIS: Update documentation 2012-04-03 13:09:18 +02:00
crypto KEYS: Document asymmetric key type 2012-10-08 13:50:12 +10:30
development-process
device-mapper md updates for 3.9 2013-03-05 17:22:08 -08:00
devicetree USB patches for 3.10-rc1 2013-04-29 12:19:23 -07:00
DocBook tty: Documentation: fix a path in a DocBook template 2013-04-03 11:45:38 -07:00
driver-model lib: devres: Introduce devm_ioremap_resource() 2013-01-22 09:41:43 -08:00
dvb [media] get_dvb_firmware: Fix the location of firmware for Terratec HTC 2013-01-01 11:18:26 -02:00
early-userspace
EDID drm: Load EDID: Explain better how to write your own EDID firmware 2013-01-20 19:22:19 +10:00
extcon Documentation/extcon: porting guide for Android kernel switch driver. 2012-04-20 09:24:27 -07:00
fault-injection doc: fix quite a few typos within Documentation 2012-11-19 14:28:24 +01:00
fb Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
filesystems Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
firmware_class firmware loader: document firmware cache mechanism 2012-11-14 15:07:18 -08:00
frv
hid HID: remove x bit from sensor doc 2012-12-14 08:48:59 +01:00
hwmon hwmon: (tmp401) Add support for TMP432 2013-04-21 08:56:48 -07:00
i2c i2c: Fix my e-mail address in drivers and documentation 2013-03-22 11:18:34 +01:00
i2o Documentation: Fix multiple typo in Documentation 2012-03-07 16:08:24 +01:00
ia64 Fix example error_injection_tool 2013-04-02 09:39:55 -07:00
ide Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
infiniband IB/ipoib: Add rtnl_link_ops support 2012-09-20 16:49:17 -04:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2013-03-11 07:49:37 -07:00
ioctl USB: cdc-wdm: implement IOCTL_WDM_MAX_COMMAND 2013-03-25 13:32:20 -07:00
isdn Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
ja_JP
kbuild Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2013-02-27 12:28:30 -08:00
kdump Add size restriction to the kdump documentation 2013-04-02 09:40:03 -07:00
ko_KR driver-core: documentation: fix up Greg's email address 2012-02-15 14:48:01 -08:00
laptops Documentation/laptops: remove depends on CONFIG_EXPERIMENTAL 2013-01-21 14:52:42 -08:00
leds Documentation: leds: update LP55xx family devices 2013-02-06 15:59:30 -08:00
m68k
make
memory-devices memory: emif: add basic infrastructure for EMIF driver 2012-05-02 00:10:49 -07:00
metag metag: Basic documentation 2013-03-02 20:09:50 +00:00
mips
misc-devices mei: bus: Add device enabling and disabling API 2013-04-08 16:57:15 -07:00
mmc mmc: core: Extend sysfs to ext_csd parameters for RPMB support 2012-12-06 13:54:48 -05:00
mn10300
mtd
namespaces userns: Recommend use of memory control groups. 2013-01-26 22:20:06 -08:00
netlabel
networking ipvs: add backup_only flag to avoid loops 2013-03-19 21:21:51 +09:00
nfc NFC: Update pn544 documentation 2013-01-10 01:27:46 +01:00
parisc Documentation: Fix typo in multiple files in Documentation 2012-04-16 14:37:13 +02:00
PCI PCI/MSI: Enable multiple MSIs with pci_enable_msi_block_auto() 2013-01-24 17:25:13 +01:00
pcmcia
power PM / OPP: improve introductory documentation 2013-03-04 14:23:11 +01:00
powerpc powerpc: Documentation for transactional memory on powerpc 2013-02-15 17:02:25 +11:00
pps
prctl seccomp: Make syscall skipping and nr changes more consistent 2012-10-02 21:14:29 +10:00
pti
ptp
rapidio
RCU Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD 2012-11-16 09:59:58 -08:00
s390 s390/s390dbf.txt: Add doc: Debug views are removed in debug_unregister() 2013-04-17 14:07:25 +02:00
scheduler sched: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW 2012-09-13 16:52:04 +02:00
scsi [SCSI] qla2xxx: Update copyright dates information in LICENSE.qla2xxx file. 2013-04-06 11:31:30 +01:00
security Documentation: fix Documentation/security/00-INDEX 2012-12-17 17:15:22 -08:00
serial tty: Update serial core API documentation 2013-01-15 21:57:44 -08:00
sh
sound Revert "ALSA: hda - Allow power_save_controller option override DCAPS" 2013-04-04 15:35:39 +02:00
spi Documentation: remove __dev* attributes. 2013-01-03 15:57:16 -08:00
sysctl mm: limit growth of 3% hardcoded other user reserve 2013-04-29 15:54:36 -07:00
target target: Simplify fabric sense data length handling 2012-09-17 17:12:58 -07:00
thermal Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2013-02-28 19:48:26 -08:00
timers
trace Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-03-11 07:54:29 -07:00
usb USB: remove CONFIG_USB_SUSPEND from Documentation 2013-03-28 14:45:56 -07:00
vDSO
video4linux [media] radio-si470x doc: add info about v4l2-ctl and sox+alsa 2013-02-13 17:33:20 -02:00
virtual Merge tag 'kvm-3.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2013-02-24 13:07:18 -08:00
vm mm: limit growth of 3% hardcoded other user reserve 2013-04-29 15:54:36 -07:00
w1 w1: w1_therm: Add force-pullup option for "broken" sensors 2013-02-18 13:55:24 -08:00
watchdog watchdog: core: dt: add support for the timeout-sec dt property 2013-03-01 12:48:36 +01:00
wimax
x86 Merge branch 'x86/microcode' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-22 19:22:52 -08:00
xtensa xtensa: initialize atomctl SR 2012-12-18 21:10:22 -08:00
zh_CN Driver core patches for 3.9-rc1 2013-02-21 12:05:51 -08:00
.gitignore
00-INDEX ImgTec Meta architecture changes for v3.9-rc1 2013-03-03 12:06:09 -08:00
applying-patches.txt
atomic_ops.txt Documentation: Memory barrier semantics of atomic_xchg() 2013-01-08 14:14:55 -08:00
bad_memory.txt
basic_profiling.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt
Changes
circular-buffers.txt
clk.txt Documentation: common clk API 2012-03-16 20:35:01 +00:00
coccinelle.txt coccicheck: Allow the user to give a V= (verbose) argument 2013-02-22 11:39:13 +01:00
CodingStyle Documentation: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:38:03 -08:00
cpu-hotplug.txt doc: Add x86 CPU0 online/offline feature 2012-11-14 09:39:44 -08:00
cpu-load.txt
cputopology.txt
crc32.txt crc32: move long comment about crc32 fundamentals to Documentation/ 2012-03-23 16:58:37 -07:00
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt firmware: remove last vestiges of dabusb 2012-11-21 13:03:01 -08:00
digsig.txt
DMA-API-HOWTO.txt Documentation/DMA-API-HOWTO.txt: fix typo 2013-02-27 19:10:23 -08:00
DMA-API.txt dma-debug: New interfaces to debug dma mapping errors 2012-10-24 17:06:43 +02:00
DMA-attributes.txt common: DMA-mapping: add DMA_ATTR_FORCE_CONTIGUOUS attribute 2012-11-29 03:30:34 -08:00
dma-buf-sharing.txt dma-buf: implement vmap refcounting in the interface logic 2013-02-27 15:13:36 +05:30
DMA-ISA-LPC.txt
dmaengine.txt Documentation: Fix multiple typo in Documentation 2012-03-07 16:08:24 +01:00
dontdiff x86: remove offsets.h from .gitignore and dontdiff 2012-11-19 14:10:53 +01:00
dynamic-debug-howto.txt dynamic_debug: dynamic hex dump 2013-01-17 12:19:09 -08:00
edac.txt Merge branch 'devel' 2012-07-29 21:11:05 -03:00
eisa.txt MCA: delete all remaining traces of microchannel bus support. 2012-05-17 19:06:13 -04:00
email-clients.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt
gpio.txt gpiolib: provide provision to register pin ranges 2012-11-11 19:06:00 +01:00
highuid.txt
HOWTO HOWTO: fix double words typo 2012-12-10 15:54:27 +01:00
hw_random.txt
hwspinlock.txt
init.txt
initrd.txt Documentation/initrd.txt: Change the location of util-linux 2012-05-25 16:18:34 +02:00
intel_txt.txt Documentation: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:38:03 -08:00
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt ipmi: add options to disable openfirmware and PCI scanning 2013-02-27 19:10:21 -08:00
IRQ-affinity.txt
IRQ-domain.txt irqdomain: update documentation 2012-12-05 23:52:10 +00:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt Kernel-doc: Convention: Use a "Return" section to describe return values 2012-11-27 21:08:57 +01:00
kernel-docs.txt
kernel-parameters.txt Merge branch 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-04-20 18:40:36 -07:00
kmemcheck.txt
kmemleak.txt
kobject.txt Documentation: Fix "struct kobj_type" to include newer members. 2012-09-04 16:06:34 -07:00
kprobes.txt
kref.txt kref: Add kref_get_unless_zero documentation 2012-11-28 18:36:06 +10:00
ldm.txt
local_ops.txt
lockdep-design.txt
lockstat.txt locking/stat: Fix a typo 2013-02-19 08:42:37 +01:00
lockup-watchdogs.txt
logo.gif
logo.txt
magic-number.txt wanrouter: completely decouple obsolete code from kernel. 2013-01-31 19:20:33 -05:00
Makefile mei: move doc files Documentation/misc-devices/mei 2012-05-09 13:59:09 -07:00
ManagementStyle Documentation: ManagementStyle: fixed typo 2012-06-28 12:03:15 +02:00
md.txt
media-framework.txt [media] Documentation/media-framework.txt: fix a sentence 2013-02-08 13:27:13 -02:00
memory-barriers.txt Documentation: Memory barrier semantics of atomic_xchg() 2013-01-08 14:14:55 -08:00
memory-hotplug.txt hotplug: update nodemasks management 2012-12-12 17:38:33 -08:00
mono.txt Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
mutex-design.txt
nommu-mmap.txt
numastat.txt Doc: Update numastat.txt 2012-02-28 16:05:06 +01:00
oops-tracing.txt
padata.txt
parport-lowlevel.txt
parport.txt Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
percpu-rw-semaphore.txt percpu-rw-semaphore: fix documentation typos 2012-09-26 19:56:15 +02:00
pi-futex.txt
pinctrl.txt pinctrl: document the "GPIO mode" pitfall 2013-03-18 11:03:29 +01:00
pnp.txt
preempt-locking.txt
printk-formats.txt Randy has moved 2013-03-08 15:05:34 -08:00
pwm.txt pwm: add devm_pwm_get() and devm_pwm_put() 2012-09-10 17:05:45 +02:00
ramoops.txt pstore/ftrace: Convert to its own enable/disable debugfs knob 2012-09-06 22:16:58 -07:00
rbtree.txt rbtree: move augmented rbtree functionality to rbtree_augmented.h 2012-10-09 16:22:40 +09:00
remoteproc.txt remoteproc: add rproc_report_crash function to notify rproc crashes 2012-09-18 12:53:22 +03:00
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt Documentation: remove __dev* attributes. 2013-01-03 15:57:16 -08:00
rt-mutex-design.txt
rt-mutex.txt
rtc.txt rtc-proc: permit the /proc/driver/rtc device to use other devices 2012-10-06 03:05:01 +09:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
SM501.txt
smsc_ece1099.txt mfd: smsc: Add support for smsc gpio io/keypad driver 2012-10-01 15:27:48 +02:00
sparse.txt Documentation/sparse.txt: document context annotations for lock checking 2012-12-17 17:15:23 -08:00
spinlocks.txt
stable_api_nonsense.txt
stable_kernel_rules.txt stable: Allow merging of backports for serious user-visible performance issues 2012-06-25 12:11:58 -07:00
static-keys.txt Documentation: Fix typo in multiple files in Documentation 2012-04-16 14:37:13 +02:00
SubmitChecklist
SubmittingDrivers
SubmittingPatches Randy has moved 2013-03-08 15:05:34 -08:00
svga.txt
sysfs-rules.txt
sysrq.txt sparc64: Add global PMU register dumping via sysrq. 2012-10-16 09:34:01 -07:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt vfio: Trivial Documentation correction 2012-09-21 10:48:03 -06:00
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt VME: Move API documentation to Documentation folder 2012-05-08 16:01:34 -07:00
volatile-considered-harmful.txt
workqueue.txt workqueue: reimplement WQ_HIGHPRI using a separate worker_pool 2012-07-13 22:24:45 -07:00
xz.txt
zorro.txt