linux/Documentation
Johannes Weiner 795ae7a0de mm: scale kswapd watermarks in proportion to memory
In machines with 140G of memory and enterprise flash storage, we have
seen read and write bursts routinely exceed the kswapd watermarks and
cause thundering herds in direct reclaim.  Unfortunately, the only way
to tune kswapd aggressiveness is through adjusting min_free_kbytes - the
system's emergency reserves - which is entirely unrelated to the
system's latency requirements.  In order to get kswapd to maintain a
250M buffer of free memory, the emergency reserves need to be set to 1G.
That is a lot of memory wasted for no good reason.

On the other hand, it's reasonable to assume that allocation bursts and
overall allocation concurrency scale with memory capacity, so it makes
sense to make kswapd aggressiveness a function of that as well.

Change the kswapd watermark scale factor from the currently fixed 25% of
the tunable emergency reserve to a tunable 0.1% of memory.

Beyond 1G of memory, this will produce bigger watermark steps than the
current formula in default settings.  Ensure that the new formula never
chooses steps smaller than that, i.e.  25% of the emergency reserve.

On a 140G machine, this raises the default watermark steps - the
distance between min and low, and low and high - from 16M to 143M.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
..
ABI [media] media: rc: nuvoton: switch attribute wakeup_data to text 2016-03-05 08:22:03 -03:00
accounting Documentation-getdelays: Apply a recommendation from "checkpatch.pl" in main() 2015-12-24 07:22:32 -07:00
acpi mfd: core: redo ACPI matching of the children devices 2015-10-26 15:25:53 +01:00
aoe
arm ARM: SoC multiplatform code changes for v4.5 2016-01-20 18:03:56 -08:00
arm64 arm64: Documentation: add list of software workarounds for errata 2015-12-11 17:33:21 +00:00
auxdisplay
backlight
blackfin
block A relatively boring cycle in the docs tree. There's a few kernel-doc 2016-01-17 11:55:07 -08:00
blockdev zram: update documentation 2015-09-24 15:39:42 -06:00
bus-devices
cdrom
cgroup-v1 cgroup: rename cgroup documentations 2016-01-11 23:14:51 -05:00
cma
connector
console
cpu-freq Documentation: cpufreq: intel_pstate: fix typo 2016-02-18 20:31:53 +01:00
cpuidle
cris
crypto KEYS: Merge the type-specific data with the payload data 2015-10-21 15:18:36 +01:00
development-process
device-mapper dm cache: make the 'mq' policy an alias for 'smq' 2016-03-10 17:12:08 -05:00
devicetree media updates for v4.6-rc1 2016-03-16 18:27:32 -07:00
dmaengine Merge branch 'topic/async' into for-linus 2016-01-06 15:17:47 +05:30
DocBook [media] V4L: add Y12I, Y8I and Z16 pixel format documentation 2016-03-03 06:29:42 -03:00
driver-model driver-core: platform: Provide helpers for multi-driver modules 2015-10-05 05:02:40 +01:00
dvb [media] media: change email address 2016-01-25 12:01:08 -02:00
early-userspace
EDID
extcon
fault-injection net: Add support for CHANGEUPPER notifier error injection 2015-12-03 11:49:23 -05:00
fb Documentation/fb: add documentation for sm712fb 2015-08-07 15:05:01 -07:00
features dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
filesystems efi: Make efivarfs entries immutable by default 2016-02-10 16:25:52 +00:00
firmware_class
fmc
fpga usage documentation for FPGA manager core 2015-10-07 18:07:20 +01:00
frv
gpio Doc: gpio: Fix typos in Documentation/gpio 2015-11-20 16:51:16 -07:00
hid
hwmon hwmon: Create an NSA320 hardware monitoring driver 2016-03-08 18:40:49 -08:00
i2c i2c: i801: add Intel Lewisburg device IDs 2015-11-20 16:22:21 +01:00
ia64
ide
iio iio: Documentation: Add IIO configfs documentation 2015-12-03 18:19:28 +00:00
infiniband IB: remove in-kernel support for memory windows 2015-12-23 14:29:04 -05:00
input Input: add userio module 2015-10-27 18:55:31 -07:00
ioctl Doc: ioctl: Fix typos in Documentation/ioctl 2015-11-20 16:52:50 -07:00
isdn
ja_JP Documentation: translations: update linux cross reference link 2016-01-11 18:26:58 -07:00
kbuild kbuild: document recursive dependency limitation / resolution 2015-10-08 15:36:16 +02:00
kdump
ko_KR Documentation: translations: update linux cross reference link 2016-01-11 18:26:58 -07:00
laptops
leds Documentation: leds: Add description of brightness setting API 2016-01-04 09:57:31 +01:00
locking Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-11-03 16:10:43 -08:00
m68k
memory-devices
metag
mic misc: mic: Update MIC host daemon with COSM changes 2015-10-04 12:54:54 +01:00
mips
misc-devices Doc:misc-devices: Fix typo in Documentation/misc-devices 2015-09-18 10:04:24 -06:00
mmc mmc: core: Remove MMC_CLKGATE 2015-10-26 16:00:09 +01:00
mn10300
mtd Documentation: mtd: improve nand_ecc.txt for readability and correctness 2015-11-17 17:05:14 -08:00
namespaces
netlabel
networking net: change tcp_syn_retries documentation 2016-01-20 18:55:08 -08:00
nfc
nios2
nvdimm libnvdimm: documentation clarifications 2015-11-12 09:55:23 -08:00
nvmem Documentation: nvmem: add nvmem api level and how-to doc 2015-08-05 13:43:45 -07:00
parisc
PCI
pcmcia pcmcia: Fix typo in locking documentation 2015-08-07 14:34:58 +02:00
phy
platform
power Merge branches 'pm-pci' and 'pm-core' 2016-01-12 01:10:52 +01:00
powerpc SCSI misc on 20150901 2015-09-02 12:22:54 -07:00
pps Doc: pps: Fix file name in pps.txt 2015-07-14 12:35:42 -06:00
prctl Documentation/prctl: don't build tsc tests when cross compiling 2015-06-22 16:05:04 -06:00
pti
ptp ptp: Add PTP_SYS_OFFSET_PRECISE for driver crosstimestamping 2016-03-03 14:23:43 -08:00
rapidio
RCU documentation: Update RCU requirements based on expedited changes 2015-12-05 12:34:32 -08:00
s390 s390/zcore: remove /sys/kernel/debug/zcore/mem 2015-11-27 09:24:12 +01:00
scheduler
scsi st: Fix MTMKPART to work with newer drives 2016-02-23 21:27:02 -05:00
security keys, trusted: seal with a TPM2 authorization policy 2015-12-20 15:27:13 +02:00
serial Documentation: improve line discipline method descriptions 2015-10-05 04:53:26 +01:00
sh
sound ASoC: img: Add documentation for SPDIF in controls 2015-11-16 10:06:58 +00:00
spi spi: tools: move spidev_test metadata 2015-11-30 12:14:12 +00:00
sysctl mm: scale kswapd watermarks in proportion to memory 2016-03-17 15:09:34 -07:00
target target: use per-attribute show and store methods 2015-10-13 22:17:49 -07:00
thermal thermal: add description for integral_cutoff unit 2016-01-14 13:29:08 -07:00
timers hpet: Drop stale URLs 2016-02-17 09:39:56 +01:00
tpm
trace x86, tracing, perf: Add trace point for MSR accesses 2015-12-06 12:56:10 +01:00
usb The chipidea changes for v4.5-rc1 2015-12-26 16:59:14 -08:00
vDSO Documentation/vDSO: don't build tests when cross compiling 2015-06-22 16:04:57 -06:00
video4linux [media] saa7134: Add support for Snazio TvPVR PRO 2016-03-03 09:03:48 -03:00
virtual One of the largest releases for KVM... Hardly any generic improvement, 2016-03-16 09:55:35 -07:00
vm thp, vmstats: count deferred split events 2016-03-17 15:09:34 -07:00
w1 w1: masters: omap_hdq: add support for 1-wire mode 2015-10-05 04:47:09 +01:00
watchdog Add sun4v_wdt watchdog driver 2016-01-31 11:06:24 -08:00
wimax
x86 Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-15 10:39:22 -07:00
xtensa
zh_CN [media] media framework: rename pads init function to media_entity_pads_init() 2016-01-11 12:19:03 -02:00
00-INDEX
adding-syscalls.txt Documentation: describe how to add a system call 2015-08-13 17:54:06 -06:00
applying-patches.txt
assoc_array.txt
atomic_ops.txt locking/atomics, cmpxchg: Privatize the inclusion of asm/cmpxchg.h 2015-09-13 10:35:46 +02:00
bad_memory.txt
basic_profiling.txt
bcache.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt
cgroup-v2.txt mm: memcontrol: report kernel stack usage in cgroup2 memory.stat 2016-03-17 15:09:34 -07:00
Changes There is a nice new document from Neil on how pathname lookups work and 2015-11-05 15:59:24 -08:00
circular-buffers.txt
clk.txt clk: change clk_ops' ->determine_rate() prototype 2015-07-27 18:12:01 -07:00
coccinelle.txt
CodeOfConflict
CodingStyle Documentation: fix typo in CodingStyle 2016-01-11 18:18:16 -07:00
cpu-hotplug.txt Documentation: cpu-hotplug: Fix sysfs mount instructions 2015-12-10 11:35:30 -07:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt Doc: Change wikipedia's URL from http to https 2015-06-22 10:14:05 -06:00
dell_rbu.txt
devices.txt
digsig.txt
DMA-API-HOWTO.txt dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
DMA-API.txt DMA-API: fix confusing sentence in Documentation/DMA-API.txt 2016-01-11 18:29:00 -07:00
DMA-attributes.txt
dma-buf-sharing.txt
DMA-ISA-LPC.txt
dontdiff Documentation: dontdiff: remove media from dontdiff 2015-11-11 10:08:07 -07:00
dynamic-debug-howto.txt
edac.txt EDAC: Remove references to bluesmoke.sourceforge.net 2015-11-26 14:46:06 +01:00
efi-stub.txt
eisa.txt
email-clients.txt A few more documentation patches that wandered in and have no reason to 2015-11-13 09:19:05 -08:00
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt
gdb-kernel-debugging.txt
highuid.txt
HOWTO Documentation: HOWTO: update code cross reference link 2015-12-10 11:19:35 -07:00
hsi.txt
hw_random.txt hwrng: doc - Fix device node name reference /dev/hw_random => /dev/hwrng 2015-09-21 22:00:41 +08:00
hwspinlock.txt
init.txt
initrd.txt
intel_txt.txt
Intel-IOMMU.txt iommu/vt-d: Fix link to Intel IOMMU Specification 2016-01-29 12:32:12 +01:00
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt ipmi watchdog : add panic_wdt_timeout parameter 2015-11-16 06:28:43 -06:00
IRQ-affinity.txt
IRQ-domain.txt irqdomain: Documentation updates 2015-10-13 19:01:25 +02:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kasan.txt mm, slub, kasan: enable user tracking by default with KASAN=y 2015-11-05 19:34:48 -08:00
kernel-doc-nano-HOWTO.txt Documenation: Update location of docproc.c 2015-07-14 12:36:39 -06:00
kernel-docs.txt Documentation: translations: update linux cross reference link 2016-01-11 18:26:58 -07:00
kernel-parameters.txt Power management and ACPI material for v4.6-rc1, part 1 2016-03-16 14:10:53 -07:00
kernel-per-CPU-kthreads.txt irq_poll: make blk-iopoll available outside the block layer 2015-12-11 11:52:24 -08:00
kmemcheck.txt
kmemleak.txt Doc: Change wikipedia's URL from http to https 2015-06-22 10:14:05 -06:00
kobject.txt
kprobes.txt
kref.txt
kselftest.txt Documentation: Update kselftest.txt 2015-09-24 15:51:53 -06:00
ldm.txt
local_ops.txt
lockup-watchdogs.txt kernel/watchdog.c: add sysctl knob hardlockup_panic 2015-11-05 19:34:48 -08:00
logo.gif
logo.txt
lzo.txt
magic-number.txt
mailbox.txt Documentation: minor typo fix in mailbox.txt 2015-08-13 18:03:18 -06:00
Makefile spi: Move spi code from Documentation to tools 2015-11-23 14:54:01 +00:00
ManagementStyle
md-cluster.txt md-cluster: update the documentation 2016-01-06 11:39:06 +11:00
md.txt doc:md: fix typo in md.txt. 2015-06-23 06:49:44 -06:00
memory-barriers.txt virtio: barrier rework+fixes 2016-01-18 16:44:24 -08:00
memory-hotplug.txt memory-hotplug: add automatic onlining policy for the newly added memory 2016-03-15 16:55:16 -07:00
men-chameleon-bus.txt Documentation: Minor changes to men-chameleon-bus.txt 2015-07-24 15:15:17 +02:00
module-signing.txt Move certificate handling to its own directory 2015-08-14 16:06:13 +01:00
mono.txt
nommu-mmap.txt
ntb.txt NTB: Rename Intel code names to platform names 2015-07-04 14:09:25 -04:00
numastat.txt
oops-tracing.txt
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt
pinctrl.txt
pnp.txt
preempt-locking.txt
printk-formats.txt mm, printk: introduce new format string for flags 2016-03-15 16:55:16 -07:00
pwm.txt
ramoops.txt
rbtree.txt documentation: fix small typo in rbtree.txt 2015-09-13 14:38:50 -06:00
remoteproc.txt remoteproc: introduce rproc_get_by_phandle API 2015-06-16 21:12:52 +03:00
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt rtc: implement a sysfs interface for clock offset 2016-03-14 17:08:16 +01:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
SM501.txt
smsc_ece1099.txt
sparse.txt
stable_api_nonsense.txt
stable_kernel_rules.txt stable_kernel_rules.txt: Remove extra space after Cc: 2015-11-20 16:54:57 -07:00
static-keys.txt locking/static_keys: Fix up the static keys documentation 2015-09-15 07:12:06 +02:00
SubmitChecklist
SubmittingDrivers
SubmittingPatches A few more documentation patches that wandered in and have no reason to 2015-11-13 09:19:05 -08:00
svga.txt
sysfs-rules.txt
sysrq.txt mm, oom: do not panic for oom kills triggered from sysrq 2015-09-08 15:35:28 -07:00
this_cpu_ops.txt
ubsan.txt UBSAN: run-time undefined behavior sanity checker 2016-01-20 17:09:18 -08:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt
volatile-considered-harmful.txt
workqueue.txt
xillybus.txt
xz.txt
zorro.txt