WSL2-Linux-Kernel/Documentation
zhouxianrong 8e19d540d1 zram: extend zero pages to same element pages
The idea is that without doing more calculations we extend zero pages to
same element pages for zram.  zero page is special case of same element
page with zero element.

1. the test is done under android 7.0
2. startup too many applications circularly
3. sample the zero pages, same pages (none-zero element)
   and total pages in function page_zero_filled

the result is listed as below:

ZERO	SAME	TOTAL
36214	17842	598196

		ZERO/TOTAL	 SAME/TOTAL	  (ZERO+SAME)/TOTAL ZERO/SAME
AVERAGE	0.060631909	 0.024990816  0.085622726		2.663825038
STDEV	0.00674612	 0.005887625  0.009707034		2.115881328
MAX		0.069698422	 0.030046087  0.094975336		7.56043956
MIN		0.03959586	 0.007332205  0.056055193		1.928985507

from the above data, the benefit is about 2.5% and up to 3% of total
swapout pages.

The defect of the patch is that when we recovery a page from non-zero
element the operations are low efficient for partial read.

This patch extends zero_page to same_page so if there is any user to
have monitored zero_pages, he will be surprised if the number is
increased but it's not harmful, I believe.

[minchan@kernel.org: do not free same element pages in zram_meta_free]
  Link: http://lkml.kernel.org/r/20170207065741.GA2567@bbox
Link: http://lkml.kernel.org/r/1483692145-75357-1-git-send-email-zhouxianrong@huawei.com
Link: http://lkml.kernel.org/r/1486307804-27903-1-git-send-email-minchan@kernel.org
Signed-off-by: zhouxianrong <zhouxianrong@huawei.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.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>
2017-02-24 17:46:56 -08:00
..
ABI First set of updates for 4.11 kernel merge window 2017-02-23 08:27:57 -08:00
DocBook A slightly quieter cycle for documentation this time around. 2017-02-22 18:51:29 -08:00
EDID
PCI Merge branch 'pci/msi' into next 2017-02-15 11:56:10 -06:00
RCU Merge branches 'doc.2017.01.15b', 'dyntick.2017.01.23a', 'fixes.2017.01.23a', 'srcu.2017.01.25a' and 'torture.2017.01.15b' into HEAD 2017-01-25 12:56:05 -08:00
accounting tools: move accounting tool from Documentation 2016-09-23 13:07:15 -06:00
acpi ACPI / button: Remove lid_init_state=method mode 2017-01-31 17:20:45 +01:00
admin-guide Merge branch 'akpm' (patches from Andrew) 2017-02-22 19:29:24 -08:00
aoe
arm arm: sunxi: add support for V3s SoC 2017-01-20 21:31:34 +01:00
arm64 arm64: Work around Falkor erratum 1003 2017-02-10 11:22:12 +00:00
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 A slightly quieter cycle for documentation this time around. 2017-02-22 18:51:29 -08:00
blockdev zram: extend zero pages to same element pages 2017-02-24 17:46:56 -08:00
bus-devices
cdrom cdrom: Make device operations read-only 2017-02-14 08:29:56 -07:00
cgroup-v1 Documentation: cpuset: Fix 'cpuset.tasks' -> 'tasks' 2017-01-13 11:04:45 -07:00
cma
connector samples: connector: from Documentation to samples directory 2016-04-28 07:47:35 -06:00
console
core-api Documentation: Update CPU hotplug and move it to core-api 2017-01-13 10:32:32 -07:00
cpu-freq A slightly quieter cycle for documentation this time around. 2017-02-22 18:51:29 -08:00
cpuidle
cris
crypto crypto: doc - fix typo 2017-02-15 13:23:49 +08:00
dev-tools Improve sparse documentation 2017-02-15 15:09:13 -07:00
device-mapper dm cache metadata: add "metadata2" feature 2017-02-16 13:12:47 -05:00
devicetree Less anger inducing pull request for 4.11 2017-02-23 18:58:18 -08:00
dmaengine dmaengine: Documentation: Fix typo in pxa_dma.txt 2016-11-14 08:14:24 +05:30
doc-guide docs-rst: parse-headers.pl: cleanup the documentation 2016-11-30 17:08:09 -07:00
driver-api Less anger inducing pull request for 4.11 2017-02-23 18:58:18 -08:00
driver-model irqdesc: Add a resource managed version of irq_alloc_descs() 2017-02-10 14:39:20 +01:00
early-userspace
extcon extcon: int3496: Add Intel INT3496 ACPI device extcon driver 2017-01-09 10:04:11 +09:00
fault-injection
fb Documentation: fb: fix spelling mistakes 2016-05-10 12:05:27 +03:00
features 2nd round of ARC udpates for 4.10rc1 2016-12-23 10:22:47 -08:00
filesystems rxrpc: Change module filename to rxrpc.ko 2017-02-17 15:09:19 -05:00
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: random documentation update 2017-01-31 15:43:05 +01:00
gpu Less anger inducing pull request for 4.11 2017-02-23 18:58:18 -08:00
hid Documentation: HID: Intel ISH HID document 2016-08-17 11:13:07 +02:00
hwmon A slightly quieter cycle for documentation this time around. 2017-02-22 18:51:29 -08:00
i2c Merge branch 'i2c/for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2016-12-15 12:56:35 -08:00
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/hfi1: Document new sysfs entries for hfi1 driver 2016-10-02 08:42:19 -04:00
input Documentation: input: fix path to input code definitions 2017-02-12 15:19:00 -07:00
ioctl rpmsg updates for v4.11 2017-02-23 09:41:03 -08:00
isdn docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
kbuild Kconfig: Introduce the "imply" keyword 2016-11-16 09:26:33 +01:00
kdump Documentation: kdump: Add description of enable multi-cpus support 2016-09-20 18:02:54 -06:00
laptops platform/x86: thinkpad_acpi: Add support for X1 Yoga (2016) Tablet Mode 2016-12-13 09:29:06 -08:00
leds leds: class: Add new optional brightness_hw_changed attribute 2017-01-29 19:59:42 +01:00
livepatch A slightly quieter cycle for documentation this time around. 2017-02-22 18:51:29 -08:00
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
media A slightly quieter cycle for documentation this time around. 2017-02-22 18:51:29 -08:00
memory-devices
metag
mic samples: move mic/mpssd example code from Documentation 2016-09-20 12:38:48 -06:00
mips
misc-devices samples: move misc-devices/mei example code from Documentation 2016-09-23 11:51:43 -06:00
mmc mmc: core: Extend sysfs with DSR register 2016-07-25 10:34:51 +02:00
mn10300
mtd spi-nor: Add support for Intel SPI serial flash controller 2017-01-03 17:33:36 +00:00
namespaces
netlabel
networking A slightly quieter cycle for documentation this time around. 2017-02-22 18:51:29 -08:00
nfc
nios2
nvdimm libnvdimm, btt: update the usage section in Documentation 2016-06-17 16:23:23 -07:00
nvmem
parisc
pcmcia tools: move pcmcia crc32hash tool from Documentation 2016-09-23 13:07:27 -06:00
perf perf: add qcom l2 cache perf events driver 2017-02-08 19:32:24 +00:00
phy
platform
power A slightly quieter cycle for documentation this time around. 2017-02-22 18:51:29 -08:00
powerpc powerpc updates for 4.9 2016-10-07 20:19:31 -07:00
pps Doc: clarify source of jitter in USB1.1, and USB2.0 2017-01-04 14:40:52 -07:00
prctl selftests: move prctl tests from Documentation/prctl 2016-09-20 09:09:09 -06:00
process Doc: Correct typo, "Introdution" => "Introduction" 2016-12-01 10:44:08 -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
s390 s390/Documentation: improve sort command for trace buffer 2016-06-13 15:58:23 +02:00
scheduler sched/Documentation/sched-rt-group: Fix incorrect example 2017-01-22 10:34:17 +01:00
scsi Merge branch 'misc' into for-linus 2016-12-22 12:32:33 -08:00
security This renames the (now inaccurate) CONFIG_DEBUG_RODATA and related config 2017-02-21 17:56:45 -08:00
serial Documentation: rs485: Do not define manually the ioctl 2016-08-18 11:08:33 -06:00
sh
sound ALSA: Documentation about HDA DP MST pin init and connection 2017-01-12 10:06:47 +01:00
sphinx docs: sphinx-extensions: make rstFlatTable work with docutils 0.13 2016-12-18 13:30:29 -07:00
sphinx-static This is the documentation update pull for the 4.9 merge window. 2016-10-04 13:54:07 -07:00
spi spi: spi-ep93xx: simplify GPIO chip selects 2017-02-16 20:10:26 +00:00
sysctl mm, madvise: fail with ENOMEM when splitting vma will hit max_map_count 2017-02-24 17:46:55 -08:00
target target: make close_session optional 2016-05-10 01:19:26 -07:00
thermal Documentation: fix spelling mistakes of "Celcius" -- > "Celsius" 2017-01-04 14:36:17 -07:00
timers time: Remove CONFIG_TIMER_STATS 2017-02-10 11:15:08 +01:00
trace trace-vmscan-postprocess: sync with tracepoints updates 2017-02-22 16:41:29 -08:00
translations Documentation: Fix linux-api list typo 2017-02-15 15:12:26 -07:00
usb A slightly quieter cycle for documentation this time around. 2017-02-22 18:51:29 -08:00
virtual KVM: race-free exit from KVM_RUN without POSIX signals 2017-02-17 12:27:37 +01:00
vm mm, madvise: fail with ENOMEM when splitting vma will hit max_map_count 2017-02-24 17:46:55 -08:00
w1 w1: add ability to set (SRAM) and store (EEPROM) configuration for temp sensors like DS18B20 2016-05-01 14:37:49 -07:00
watchdog docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
wimax
x86 efi: Get and store the secure boot status 2017-02-07 10:42:10 +01:00
xtensa xtensa: cleanup MMU setup and kernel layout macros 2016-07-24 06:33:58 +03:00
.gitignore Add .pyc files to .gitignore 2016-06-30 13:07:33 -06:00
00-INDEX edac: adjust docs location at MAINTAINERS and 00-INDEX 2016-12-15 08:57:16 -02:00
Changes docs: add back 'Documentation/Changes' file (as symlink) 2016-12-14 16:30:12 -08:00
CodingStyle doc: re-add CodingStyle and SubmittingPatches 2016-10-24 08:12:35 -02:00
DMA-API-HOWTO.txt Documentation: DMA-API-HOWTO: Fix a typo 2016-09-20 17:58:46 -06:00
DMA-API.txt dma-mapping: add dma_{map,unmap}_resource 2016-09-26 22:16:41 +05:30
DMA-ISA-LPC.txt Documentation: DMA-ISA-LPC.txt 2017-02-12 15:20:07 -07:00
DMA-attributes.txt common: DMA-mapping: add DMA_ATTR_PRIVILEGED attribute 2017-01-19 15:56:19 +00:00
IPMI.txt ipmi: Update documentation 2016-11-07 12:16:06 -06:00
IRQ-affinity.txt
IRQ-domain.txt Documentation/IRQ-domain.txt: Document irq_domain_create_{linear, tree} 2016-03-31 00:32:59 -06:00
IRQ.txt
Intel-IOMMU.txt
Makefile samples: move blackfin gptimers-example from Documentation 2016-10-10 07:12:02 -06:00
Makefile.sphinx Add a target to check broken external links in the Documentation 2017-02-15 15:22:47 -07:00
SAK.txt
SM501.txt
SubmittingPatches doc: re-add CodingStyle and SubmittingPatches 2016-10-24 08:12:35 -02:00
bcache.txt bcache: documentation formatting, edited for clarity, stripe alignment notes 2016-06-23 07:58:38 -06:00
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
cachetlb.txt
cgroup-v2.txt Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2016-03-21 10:05:13 -07:00
circular-buffers.txt Documentation: circular-buffers: use READ_ONCE() 2016-11-16 16:17:45 -07:00
clk.txt Documentation: clk: update file names containing referenced structures 2016-08-14 12:12:36 -06:00
conf.py docs: Remove the copyright year from conf.py 2017-02-06 11:52:19 -07:00
cpu-load.txt
cputopology.txt topology/sysfs: provide drawer id and siblings attributes 2016-06-13 15:58:27 +02:00
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
digsig.txt
docutils.conf doc-rst: add docutils config file 2016-08-14 11:52:40 -06:00
dontdiff Documentation: dontdiff: Update with additional entries 2017-01-26 15:08:06 -07:00
efi-stub.txt
eisa.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcc-plugins.txt GCC plugin infrastructure 2016-06-07 22:57:10 +02:00
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst docs/zh_CN: Add coding-style into docs build system 2017-01-26 15:30:34 -07:00
intel_txt.txt
io-mapping.txt
io_ordering.txt
iostats.txt
irqflags-tracing.txt
isa.txt Documentation: Add ISA bus driver documentation 2016-05-02 09:32:04 -07:00
isapnp.txt
kernel-doc-nano-HOWTO.txt docs-rst: doc-guide: split the kernel-documentation.rst contents 2016-11-19 10:22:04 -07:00
kernel-per-CPU-kthreads.txt docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
kobject.txt
kprobes.txt Documentation: kprobes: Document jprobes stack copying limitations 2016-08-15 10:19:11 -06:00
kref.txt
kselftest.txt Doc: update kselftest.txt with details on how to run tests after install 2016-11-07 18:04:18 -07:00
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
lzo.txt Documentation: lzo: fix spelling mistakes 2016-04-28 07:23:11 -06:00
mailbox.txt
md-cluster.txt md-cluster: change array_sectors and update size are not supported 2016-05-04 12:39:35 -07:00
memory-barriers.txt doc: Update control-dependencies section of memory-barriers.txt 2017-01-14 21:29:15 -08:00
memory-hotplug.txt docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
men-chameleon-bus.txt
nommu-mmap.txt
ntb.txt
numastat.txt
padata.txt
parport-lowlevel.txt
percpu-rw-semaphore.txt
phy.txt phy: core: Allow children node to be overridden 2016-04-29 16:39:39 +02:00
pi-futex.txt
pinctrl.txt pinctrl: core: Fix regression caused by delayed work for hogs 2017-01-13 16:25:17 +01:00
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 pwm: Update documentation 2016-05-17 14:48:04 +02:00
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 Documentation: robust-futexes: fix spelling mistakes 2016-04-28 07:26:41 -06:00
rpmsg.txt rpmsg: use module_rpmsg_driver in existing drivers and examples 2016-05-06 11:09:01 -07:00
rtc.txt rtc: implement a sysfs interface for clock offset 2016-03-14 17:08:16 +01:00
sgi-ioc4.txt
siphash.txt siphash: implement HalfSipHash1-3 for hash tables 2017-01-09 13:58:57 -05:00
smsc_ece1099.txt
static-keys.txt jump_labels: Allow array initialisers 2016-09-07 09:41:11 +01:00
svga.txt
sync_file.txt dma-buf: Rename struct fence to dma_fence 2016-10-25 14:40:39 +02:00
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
unshare.txt
vfio-mediated-device.txt vfio-mdev: Make mdev_parent private 2016-12-30 08:13:41 -07:00
vfio.txt
video-output.txt
xillybus.txt Documentation: xillybus: fix spelling mistake 2016-04-28 07:44:54 -06:00
xz.txt
zorro.txt