linux/Documentation
Michal Hocko dcda9b0471 mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic
__GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to
the page allocator.  This has been true but only for allocations
requests larger than PAGE_ALLOC_COSTLY_ORDER.  It has been always
ignored for smaller sizes.  This is a bit unfortunate because there is
no way to express the same semantic for those requests and they are
considered too important to fail so they might end up looping in the
page allocator for ever, similarly to GFP_NOFAIL requests.

Now that the whole tree has been cleaned up and accidental or misled
usage of __GFP_REPEAT flag has been removed for !costly requests we can
give the original flag a better name and more importantly a more useful
semantic.  Let's rename it to __GFP_RETRY_MAYFAIL which tells the user
that the allocator would try really hard but there is no promise of a
success.  This will work independent of the order and overrides the
default allocator behavior.  Page allocator users have several levels of
guarantee vs.  cost options (take GFP_KERNEL as an example)

 - GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_
   attempt to free memory at all. The most light weight mode which even
   doesn't kick the background reclaim. Should be used carefully because
   it might deplete the memory and the next user might hit the more
   aggressive reclaim

 - GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic
   allocation without any attempt to free memory from the current
   context but can wake kswapd to reclaim memory if the zone is below
   the low watermark. Can be used from either atomic contexts or when
   the request is a performance optimization and there is another
   fallback for a slow path.

 - (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) -
   non sleeping allocation with an expensive fallback so it can access
   some portion of memory reserves. Usually used from interrupt/bh
   context with an expensive slow path fallback.

 - GFP_KERNEL - both background and direct reclaim are allowed and the
   _default_ page allocator behavior is used. That means that !costly
   allocation requests are basically nofail but there is no guarantee of
   that behavior so failures have to be checked properly by callers
   (e.g. OOM killer victim is allowed to fail currently).

 - GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior
   and all allocation requests fail early rather than cause disruptive
   reclaim (one round of reclaim in this implementation). The OOM killer
   is not invoked.

 - GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator
   behavior and all allocation requests try really hard. The request
   will fail if the reclaim cannot make any progress. The OOM killer
   won't be triggered.

 - GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior
   and all allocation requests will loop endlessly until they succeed.
   This might be really dangerous especially for larger orders.

Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL
because they already had their semantic.  No new users are added.
__alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if
there is no progress and we have already passed the OOM point.

This means that all the reclaim opportunities have been exhausted except
the most disruptive one (the OOM killer) and a user defined fallback
behavior is more sensible than keep retrying in the page allocator.

[akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c]
[mhocko@suse.com: semantic fix]
  Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz
[mhocko@kernel.org: address other thing spotted by Vlastimil]
  Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:03 -07:00
..
ABI for-f2fs-4.13 2017-07-10 14:29:45 -07:00
accounting tools: move accounting tool from Documentation 2016-09-23 13:07:15 -06:00
acpi This is the bulk of GPIO changes for the v4.13 series: 2017-07-07 12:40:27 -07:00
admin-guide Merge branch 'akpm' (patches from Andrew) 2017-07-06 22:27:08 -07:00
aoe
arm ARM: at91: Documentation: add armv7m families 2017-06-02 10:11:09 +02:00
arm64 IOMMU Updates for Linux v4.13 2017-07-12 10:00:04 -07:00
auxdisplay samples: move auxdisplay example code from Documentation 2016-09-23 11:52:32 -06:00
backlight
blackfin samples: move blackfin gptimers-example from Documentation 2016-10-10 07:12:02 -06:00
block bio-integrity: fold bio_integrity_enabled to bio_integrity_prep 2017-07-03 16:56:24 -06:00
blockdev remove the mg_disk driver 2017-04-14 14:00:49 -06:00
bus-devices
cdrom cdrom: Make device operations read-only 2017-02-14 08:29:56 -07:00
cgroup-v1 mm, vmpressure: pass-through notification support 2017-07-10 16:32:31 -07:00
cma
connector
console
core-api There has been a fair amount of activity in the docs tree this time 2017-07-03 21:13:25 -07:00
cpu-freq cpufreq: intel_pstate: Document the current behavior and user interface 2017-05-14 02:06:03 +02:00
cpuidle
cris
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-07-05 12:22:23 -07:00
dev-tools linux-kselftest-4.13-rc1-update 2017-07-07 14:04:47 -07:00
device-mapper dm zoned: drive-managed zoned block device target 2017-06-19 11:05:20 -04:00
devicetree Merge branch 'i2c/for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2017-07-12 10:04:56 -07:00
dmaengine dmaengine: Documentation: Fix typo in pxa_dma.txt 2016-11-14 08:14:24 +05:30
doc-guide kernel-doc: describe the `literal` syntax 2017-05-16 08:44:24 -03:00
driver-api Merge branch 'i2c/for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2017-07-12 10:04:56 -07:00
driver-model pci-v4.13-changes 2017-07-08 15:51:57 -07:00
early-userspace Documentation: Fix dead URLs to ftp.kernel.org 2017-03-29 15:46:06 -06:00
EDID drm: use .hword to represent 16-bit numbers 2017-03-30 10:15:19 +02:00
extcon extcon: Remove porting compatibility of swich class 2017-04-06 10:55:24 +09:00
fault-injection fault-inject: support systematic fault injection 2017-07-12 16:26:01 -07:00
fb docs: update old references for DocBook from the documentation 2017-05-16 08:44:19 -03:00
features powerpc updates for 4.12 part 1. 2017-05-05 11:36:44 -07:00
filesystems procfs: fdinfo: extend information about epoll target files 2017-07-12 16:26:01 -07:00
firmware_class firmware: revamp firmware documentation 2017-01-11 09:42:59 +01:00
fmc
fpga fpga: Add scatterlist based programming 2017-02-10 15:20:44 +01:00
frv docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
gpio gpio: return NULL from gpiod_get_optional when GPIOLIB is disabled 2017-03-15 11:16:30 +01:00
gpu main drm pull for v4.13 2017-07-09 18:48:37 -07:00
hid Documentation: hid: fix path to input bus definitions 2017-03-13 17:15:19 -06:00
hwmon hwmon: (pmbus) move header file out of I2C realm 2017-06-11 17:08:19 -07:00
i2c i2c: i801: Add support for Intel Cannon Lake 2017-06-19 16:17:41 +02:00
ia64 selftests: move ia64 tests from Documentation/ia64 2016-09-20 09:58:12 -06:00
ide
iio iio: Documentation: Correct the path used to create triggers. 2016-10-01 00:49:58 -06:00
infiniband IB/opa-vnic: Virtual Network Interface Controller (VNIC) documentation 2017-04-20 12:01:06 -04:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2017-05-26 16:45:13 -07:00
ioctl scsi: cxlflash: Introduce host ioctl support 2017-06-26 15:01:11 -04:00
isdn docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
kbuild Kbuild thin archives updates for v4.13 2017-07-07 15:11:12 -07:00
kdump kexec/kdump: minor Documentation updates for arm64 and Image 2017-07-12 16:26:00 -07:00
kernel-hacking There has been a fair amount of activity in the docs tree this time 2017-07-03 21:13:25 -07:00
laptops platform/x86: thinkpad_acpi: Add support for X1 Yoga (2016) Tablet Mode 2016-12-13 09:29:06 -08:00
leds Documentaion: leds: leds-lp55xx.txt: Fix typos 2017-03-17 13:06:14 -06:00
lightnvm lightnvm: physical block device (pblk) target 2017-04-16 10:06:33 -06:00
livepatch livepatch: allow removal of a disabled patch 2017-03-08 09:38:43 +01:00
locking locking/ww_mutex/Documentation: Update the design document 2017-01-14 11:14:55 +01:00
m68k docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
md Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-05-03 10:05:38 -07:00
media media updates for v4.13-rc1 2017-07-06 11:15:19 -07:00
memory-devices
metag
mic samples: move mic/mpssd example code from Documentation 2016-09-20 12:38:48 -06:00
mips
misc-devices Documentation: misc-devices: Add Documentation for pci-endpoint-test driver 2017-04-28 10:23:19 -05:00
mmc MMC core: 2017-05-02 17:34:32 -07:00
mn10300
mtd spi-nor: Add support for Intel SPI serial flash controller 2017-01-03 17:33:36 +00:00
namespaces
netlabel
networking doc: SKB_GSO_[IPIP|SIT] have been replaced 2017-07-08 11:25:56 +01:00
nfc
nios2
nvdimm
nvmem
parisc
PCI docs: update old references for DocBook from the documentation 2017-05-16 08:44:19 -03:00
pcmcia tools: move pcmcia crc32hash tool from Documentation 2016-09-23 13:07:27 -06:00
perf perf: qcom: Add L3 cache PMU driver 2017-04-03 18:53:50 +01:00
phy
platform
power power supply and reset changes for the v4.13 series 2017-07-04 14:25:14 -07:00
powerpc powerpc updates for 4.13 2017-07-07 13:55:45 -07:00
pps Doc: clarify source of jitter in USB1.1, and USB2.0 2017-01-04 14:40:52 -07:00
process Kbuild thin archives updates for v4.13 2017-07-07 15:11:12 -07:00
pti
ptp selftests: move ptp tests from Documentation/ptp 2016-09-20 09:54:38 -06:00
rapidio rapidio/documentation/mport_cdev: add missing parameter description 2016-09-01 17:52:02 -07:00
RCU rcu: Remove debugfs tracing 2017-06-08 18:52:43 -07:00
s390 docs: add documentation for vfio-ccw 2017-03-31 12:55:11 +02:00
scheduler sched/deadline: Add documentation about GRUB reclaiming 2017-06-08 10:31:56 +02:00
scsi scsi: make asynchronous aborts mandatory 2017-04-06 13:07:33 -04:00
security docs: Fix some formatting issues in request-key.rst 2017-05-18 10:46:25 -06:00
serial tty: n_gsm: do not send/receive in ldisc close path 2017-06-03 18:48:52 +09:00
sh docs-rst: convert sh book to ReST 2017-05-16 08:44:18 -03:00
sound sound updates for 4.13-rc1 2017-07-06 10:56:51 -07:00
sparc Documentation/sparc: Steps for sending break on sunhv console 2017-02-23 08:27:25 -08:00
sphinx Docs: clean up some DocBook loose ends 2017-06-23 14:17:38 -06:00
sphinx-static This is the documentation update pull for the 4.9 merge window. 2016-10-04 13:54:07 -07:00
spi spi: Document SPI slave controller support 2017-05-26 13:11:00 +01:00
sysctl mm: document highmem_is_dirtyable sysctl 2017-07-10 16:32:32 -07:00
target Documentation/target: add an example script to configure an iSCSI target 2017-05-01 22:21:35 -07:00
thermal Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2017-05-12 11:58:45 -07:00
timers rcu: Eliminate NOCBs CPU-state Kconfig options 2017-06-08 18:52:43 -07:00
trace Char/Misc patches for 4.13-rc1 2017-07-03 20:55:59 -07:00
translations doc/kokr/howto: Only send regression fixes after -rc1 2017-06-22 10:25:22 -06:00
usb usb: gadget: add f_uac1 variant based on a new u_audio api 2017-06-19 09:22:47 +03:00
userspace-api doc: ReSTify no_new_privs.txt 2017-05-18 10:30:09 -06:00
virtual kvm: x86: mmu: allow A/D bits to be disabled in an mmu 2017-07-03 11:19:54 +02:00
vm ksm: introduce ksm_max_page_sharing per page deduplication limit 2017-07-06 16:24:31 -07:00
w1 w1: add documentation for w1_ds2438 2017-03-17 15:10:49 +09:00
watchdog watchdog: uniphier: add UniPhier watchdog driver 2017-07-03 13:58:55 +02:00
wimax
x86 x86/mce: Update bootlog description to reflect behavior on AMD 2017-06-14 07:32:10 +02:00
xtensa of: update ePAPR references to point to Devicetree Specification 2017-06-22 11:22:06 -05:00
.gitignore
00-INDEX linux-kselftest-4.13-rc1-update 2017-07-07 14:04:47 -07:00
bcache.txt
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
cachetlb.txt
cgroup-v2.txt mm/oom_kill: count global and memory cgroup oom kills 2017-07-06 16:24:35 -07:00
Changes docs: add back 'Documentation/Changes' file (as symlink) 2016-12-14 16:30:12 -08:00
circular-buffers.txt Documentation: circular-buffers: use READ_ONCE() 2016-11-16 16:17:45 -07:00
clk.txt
CodingStyle doc: re-add CodingStyle and SubmittingPatches 2016-10-24 08:12:35 -02:00
conf.py Docs: Fix breakage with Sphinx 1.5 and upper 2017-06-23 13:45:37 -06:00
cpu-load.txt
cputopology.txt docs: Fix a couple typos 2017-04-27 15:54:39 -06:00
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt docs: Fix a couple typos 2017-04-27 15:54:39 -06:00
dell_rbu.txt
digsig.txt
DMA-API-HOWTO.txt dma-mapping: remove DMA_ERROR_CODE 2017-06-28 06:54:37 -07:00
DMA-API.txt Documentation: DMA API: fix a typo in a function name 2017-06-05 15:57:02 -06:00
DMA-attributes.txt common: DMA-mapping: add DMA_ATTR_PRIVILEGED attribute 2017-01-19 15:56:19 +00:00
DMA-ISA-LPC.txt mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
docutils.conf
dontdiff GCC plugin updates: 2017-07-05 11:46:59 -07:00
efi-stub.txt
eisa.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcc-plugins.txt gcc-plugins: update architecture list in documentation 2017-03-21 22:20:05 +11:00
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst Make the main documentation title less Geocities 2017-06-23 14:02:27 -06:00
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt Documentation: Fix a typo in IPMI.txt. 2017-01-05 15:01:54 -06:00
IRQ-affinity.txt
IRQ-domain.txt Documentation: Update IRQ-domain.txt to document irq_domain_mapping 2017-05-22 22:29:45 +02:00
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
kernel-doc-nano-HOWTO.txt docs: update old references for DocBook from the documentation 2017-05-16 08:44:19 -03:00
kernel-per-CPU-kthreads.txt rcu: Eliminate NOCBs CPU-state Kconfig options 2017-06-08 18:52:43 -07:00
kobject.txt
kprobes.txt
kref.txt Revert "kref: double kref_put() in my_data_handler()" 2017-04-08 18:38:10 +02:00
ldm.txt
lockup-watchdogs.txt docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
logo.gif
logo.txt
lsm.txt docs-rst: convert lsm from DocBook to ReST 2017-05-16 08:44:19 -03:00
lzo.txt
mailbox.txt
Makefile docs: remove DocBook from the building system 2017-05-16 08:44:19 -03:00
memory-barriers.txt There has been a fair amount of activity in the docs tree this time 2017-07-03 21:13:25 -07:00
memory-hotplug.txt mm, memory_hotplug: support movable_node for hotpluggable nodes 2017-07-10 16:32:31 -07:00
men-chameleon-bus.txt
nommu-mmap.txt
ntb.txt
numastat.txt
padata.txt
parport-lowlevel.txt
percpu-rw-semaphore.txt
phy.txt Documentation: phy: Fix repetition of word 'the' 2017-03-09 00:33:15 -07:00
pi-futex.txt
pnp.txt
preempt-locking.txt
printk-formats.txt vsprintf: Add %p extension "%pOF" for device tree 2017-06-27 12:36:40 -05:00
pwm.txt
rbtree.txt
remoteproc.txt remoteproc: Split driver and consumer dereferencing 2016-10-02 22:50:21 -07:00
rfkill.txt docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt
SAK.txt
sgi-ioc4.txt
siphash.txt siphash: implement HalfSipHash1-3 for hash tables 2017-01-09 13:58:57 -05:00
SM501.txt
smsc_ece1099.txt
static-keys.txt docs: Fix a couple typos 2017-04-27 15:54:39 -06:00
SubmittingPatches doc: re-add CodingStyle and SubmittingPatches 2016-10-24 08:12:35 -02:00
svga.txt
switchtec.txt switchtec: Add IOCTLs to the Switchtec driver 2017-04-12 12:23:37 -05:00
sync_file.txt sync_file.txt: standardize document format 2017-05-24 13:01:27 -03:00
tee.txt Documentation: tee subsystem and op-tee driver 2017-03-10 14:51:57 +01:00
this_cpu_ops.txt
unaligned-memory-access.txt Documentation/unaligned-memory-access.txt: fix incorrect comparison operator 2016-12-27 13:08:42 -07:00
vfio-mediated-device.txt docs: Fix a spelling error in vfio-mediated-device.txt 2017-04-27 15:54:39 -06:00
vfio.txt
video-output.txt
xillybus.txt
xz.txt
zorro.txt docs: Fix a couple typos 2017-04-27 15:54:39 -06:00