linux/Documentation
Minchan Kim cd67e10ac6 zram: promote zram from staging
Zram has lived in staging for a LONG LONG time and have been
fixed/improved by many contributors so code is clean and stable now.  Of
course, there are lots of product using zram in real practice.

The major TV companys have used zram as swap since two years ago and
recently our production team released android smart phone with zram
which is used as swap, too and recently Android Kitkat start to use zram
for small memory smart phone.  And there was a report Google released
their ChromeOS with zram, too and cyanogenmod have been used zram long
time ago.  And I heard some disto have used zram block device for tmpfs.
In addition, I saw many report from many other peoples.  For example,
Lubuntu start to use it.

The benefit of zram is very clear.  With my experience, one of the
benefit was to remove jitter of video application with backgroud memory
pressure.  It would be effect of efficient memory usage by compression
but more issue is whether swap is there or not in the system.  Recent
mobile platforms have used JAVA so there are many anonymous pages.  But
embedded system normally are reluctant to use eMMC or SDCard as swap
because there is wear-leveling and latency issues so if we do not use
swap, it means we can't reclaim anoymous pages and at last, we could
encounter OOM kill.  :(

Although we have real storage as swap, it was a problem, too.  Because
it sometime ends up making system very unresponsible caused by slow swap
storage performance.

Quote from Luigi on Google
 "Since Chrome OS was mentioned: the main reason why we don't use swap
  to a disk (rotating or SSD) is because it doesn't degrade gracefully
  and leads to a bad interactive experience.  Generally we prefer to
  manage RAM at a higher level, by transparently killing and restarting
  processes.  But we noticed that zram is fast enough to be competitive
  with the latter, and it lets us make more efficient use of the
  available RAM.  " and he announced.
http://www.spinics.net/lists/linux-mm/msg57717.html

Other uses case is to use zram for block device.  Zram is block device
so anyone can format the block device and mount on it so some guys on
the internet start zram as /var/tmp.
http://forums.gentoo.org/viewtopic-t-838198-start-0.html

Let's promote zram and enhance/maintain it instead of removing.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-30 16:56:55 -08:00
..
ABI Documentation: fix multiple typo occurences s/KenelVersion/KernelVersion/ 2014-01-29 16:22:40 -08:00
accounting Documentation/accounting/getdelays.c: avoid strncpy in accounting tool 2013-07-03 16:08:06 -07:00
acpi ACPI and power management updates for 3.14-rc1 2014-01-24 15:51:02 -08:00
aoe aoe: remove do-nothing NAME="%k" term from example udev rules 2013-09-11 15:59:28 -07:00
arm ARM: SoC platform changes for 3.14 2014-01-23 18:40:49 -08:00
arm64 arm64: Use 42-bit address space with 64K pages 2013-11-05 17:23:52 +00:00
auxdisplay
backlight backlight: lp855x_bl: support new LP8555 device 2013-11-13 12:09:14 +09:00
blackfin
block Linux 3.13-rc6 2013-12-31 09:51:02 -07:00
blockdev zram: promote zram from staging 2014-01-30 16:56:55 -08:00
bus-devices ARM: OMAP2+: gpmc: generic timing calculation 2012-11-09 18:07:11 +05:30
cdrom
cgroups Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-01-25 11:17:34 -08:00
connector connector - documentation: simplify netlink message length assignment 2013-10-02 16:03:51 -04:00
console TTY:console: update document console.txt 2013-05-21 10:21:57 -07:00
cpu-freq Documentation: cpufreq / boost: Update BOOST documentation 2014-01-17 02:00:45 +01:00
cpuidle cpuidle: remove cpuidle_unregister_governor() 2013-10-30 01:21:24 +01:00
cris
crypto drivers/dma: remove unused support for MEMSET operations 2013-07-03 16:07:42 -07:00
development-process Documentation: development-process: Update -mm and -next URLs 2013-07-25 12:37:24 +02:00
device-mapper dm cache: add policy name to status output 2014-01-16 13:44:11 -05:00
devicetree Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2014-01-29 20:49:12 -08:00
DocBook Merge branch 'master' into for-next 2013-12-19 15:08:32 +01:00
driver-model Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2014-01-22 21:21:55 -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 Documentation: remove reference to 2.7 kernel in early-userspace 2013-08-20 12:47:28 +02:00
EDID drm: Add 1600x1200 (UXGA) screen resolution to the built-in EDIDs 2013-04-12 14:06:16 +10:00
extcon extcon: fix switch class porting guide (Documentation) 2014-01-07 11:54:28 +09:00
fault-injection doc: fix quite a few typos within Documentation 2012-11-19 14:28:24 +01:00
fb Documentation/fb/viafb.modes fix a typo 2013-08-20 12:41:11 +02:00
filesystems Merge branch 'for-3.14' of git://linux-nfs.org/~bfields/linux 2014-01-30 10:18:43 -08:00
firmware_class firmware loader: document firmware cache mechanism 2012-11-14 15:07:18 -08:00
fmc doc: Fix typo "is is" in Documentations 2013-08-27 10:50:52 +02:00
frv
gpio gpiolib: return -ENOENT if no GPIO mapping exists 2013-12-12 19:33:59 +01:00
hid HID: uhid: use generic hidinput_input_event() 2013-07-31 10:33:05 +02:00
hwmon Update Jean Delvare's e-mail address 2014-01-29 20:40:08 +01:00
i2c Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2014-01-29 19:56:20 -08:00
i2o
ia64 Fix example error_injection_tool 2013-04-02 09:39:55 -07:00
ide
infiniband IB/ipoib: Add rtnl_link_ops support 2012-09-20 16:49:17 -04:00
input Input: fix typos in Documentation/input/gamepad.txt 2013-12-18 08:47:43 -08:00
ioctl s390/hypfs: add interface for diagnose 0x304 2014-01-24 09:40:59 +01:00
isdn
ja_JP Documentation: ja_JP: Update broken link to tpp 2013-12-10 23:09:08 -08:00
kbuild Documentation/kbuild/kconfig.txt: 'make listnewconfig' replaces: yes "" | make oldconfig 2013-10-08 23:51:50 +02:00
kdump Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-07-04 11:40:58 -07:00
ko_KR Documentation: HOWTO: Updates on subsystem trees, patchwork, -next (vs. -mm) in ko_KR 2014-01-08 15:32:51 -08:00
laptops Documentation: Fix size parameter for snprintf 2014-01-02 10:47:33 +01:00
leds leds: lp5523: Support LED MUX configuration on running a pattern 2014-01-27 17:28:48 -08:00
m68k block: remove refs to XD disks from documentation 2013-05-17 15:17:12 +02:00
make
memory-devices
metag doc: fix misspellings with 'codespell' tool 2013-05-28 12:02:12 +02:00
mic misc: mic: Fix endianness issues. 2013-11-27 11:03:38 -08:00
mips
misc-devices Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging 2014-01-29 18:56:27 -08:00
mmc mmc: core: Add in support to expose PRV for v4 MMCs 2013-03-22 12:10:42 -04:00
mn10300
mtd mtd: nand: pxa3xx: Add documentation about the controller 2014-01-03 11:22:09 -08:00
namespaces userns: Recommend use of memory control groups. 2013-01-26 22:20:06 -08:00
netlabel
networking net: Document promote_secondaries 2014-01-27 20:39:21 -08:00
nfc NFC: Update pn544 documentation 2013-01-10 01:27:46 +01:00
parisc parisc: document the shadow registers 2013-07-09 22:09:19 +02:00
PCI Merge branch 'pci/msi' into next 2014-01-07 17:34:39 -07:00
pcmcia
power Documentation/: update FireWire debugging documentation 2014-01-12 18:54:38 +01:00
powerpc powerpc: Update the 00-Index in Documentation/powerpc 2013-08-27 14:44:27 +10:00
pps USB: serial: invoke dcd_change ldisc's handler. 2013-09-26 09:45:40 -07:00
prctl seccomp: Make syscall skipping and nr changes more consistent 2012-10-02 21:14:29 +10:00
pti
ptp ptp: add the PTP_SYS_OFFSET ioctl to the testptp program 2013-09-23 16:46:17 -04:00
rapidio doc: Fix typo in doucmentations 2013-07-25 12:34:15 +02:00
RCU Merge branches 'doc.2013.12.03a', 'fixes.2013.12.12a', 'rcutorture.2013.12.03a' and 'sparse.2013.12.12a' into HEAD 2013-12-12 12:35:38 -08:00
s390 qeth: bridgeport support - address notifications 2014-01-15 14:48:01 -08:00
scheduler H8/300 has been dead for several years, the kernel for it has 2013-11-12 14:13:14 +09:00
scsi Main batch of InfiniBand/RDMA changes for 3.14: 2014-01-24 17:18:32 -08:00
security ima: update IMA-templates.txt documentation 2014-01-03 07:42:59 -05:00
serial serial: core: delete .set_wake() callback 2013-10-16 13:16:19 -07:00
sh
sound ASoC: docs: Update the Overview document 2014-01-07 17:56:32 +00:00
spi spi: Correction to typos in Documentation/spi/spi-summary 2013-12-09 17:22:19 +00:00
sysctl mm: document improved handling of swappiness==0 2014-01-29 16:22:39 -08:00
target target: Remove TF_CIT_TMPL macro 2013-10-16 13:35:02 -07:00
thermal thermal: thermal_core: allow binding with limits on bind_params 2013-09-03 09:10:24 -04:00
timers doc: add missing files to timers/00-INDEX 2013-10-27 21:55:50 +00:00
tpm drivers/tpm: add xen tpmfront interface 2013-08-09 10:57:06 -04:00
trace Documentation/trace/postprocess/trace-vmscan-postprocess.pl: fix the traceevent regex 2014-01-23 16:36:52 -08:00
usb doc: Fix typo in USB Gadget Documentation 2014-01-10 15:33:54 +01:00
vDSO
video4linux [media] V4L: Add support for integer menu controls with standard menu items 2013-08-18 07:12:59 -03:00
virtual Merge tag 'kvm-arm-for-3.14' of git://git.linaro.org/people/christoffer.dall/linux-kvm-arm into kvm-queue 2014-01-15 12:14:29 +01:00
vm mm: documentation: remove hopelessly out-of-date locking doc 2014-01-23 16:36:50 -08:00
w1 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-07-04 11:40:58 -07:00
watchdog watchdog: delete mpcore_wdt driver 2013-07-11 21:47:58 +02:00
wimax
x86 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2014-01-22 21:21:55 -08:00
xtensa xtensa: remap io area defined in device tree 2014-01-15 00:25:14 +04:00
zh_CN Documentation: zh_CN: Update broken link to tpp 2013-12-10 23:09:08 -08:00
.gitignore
00-INDEX doc: fix a typo in Documentation/00-INDEX 2013-08-27 10:53:07 +02:00
applying-patches.txt
assoc_array.txt KEYS: Fix multiple key add into associative array 2013-12-02 11:24:18 +00:00
atomic_ops.txt Documentation: Memory barrier semantics of atomic_xchg() 2013-01-08 14:14:55 -08:00
bad_memory.txt
basic_profiling.txt
bcache.txt Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-07-04 11:40:58 -07:00
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt Documentation: fix typo and update version in cachetlb.txt 2013-08-20 12:46:52 +02:00
Changes remove obsolete references to powertweak 2013-11-27 20:34:32 -08:00
circular-buffers.txt documentation: Update circular buffer for load-acquire/store-release 2013-12-03 10:08:57 -08:00
clk.txt clk: Add set_rate_and_parent() op 2014-01-16 12:00:57 -08:00
coccinelle.txt Coccinelle: Update information about the minimal version required 2013-07-03 22:58:20 +02:00
CodingStyle Documentation/CodingStyle: allow multiple return statements per function 2013-07-03 16:08:01 -07:00
cpu-hotplug.txt Documentation/cpu-hotplug.txt: fix a typo in example code 2014-01-23 16:37:01 -08:00
cpu-load.txt
cputopology.txt doc: Documentation/cputopology.txt fix typo 2013-09-04 12:59:47 +02:00
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt firewire: Enable remote DMA above 4 GB 2014-01-20 01:11:13 +01:00
dell_rbu.txt
devices.txt misc: Reserve minor for VFIO 2013-12-19 10:17:11 -07:00
digsig.txt
DMA-API-HOWTO.txt DMA-API: provide a helper to set both DMA and coherent DMA masks 2013-09-17 15:32:37 +01:00
DMA-API.txt DMA-API: provide a helper to set both DMA and coherent DMA masks 2013-09-17 15:32:37 +01:00
DMA-attributes.txt doc: Documentation/DMA-attributes.txt fix typo 2013-10-14 15:50:53 +02:00
dma-buf-sharing.txt dma-buf: Expose buffer size to userspace (v2) 2013-09-10 11:36:45 +05:30
DMA-ISA-LPC.txt
dmaengine.txt
dmatest.txt dmatest: add a 'wait' parameter 2013-11-14 11:04:40 -08:00
dontdiff x86: remove offsets.h from .gitignore and dontdiff 2012-11-19 14:10:53 +01:00
dynamic-debug-howto.txt dynamic-debug-howto.txt: update since new wildcard support 2014-01-23 16:36:55 -08:00
edac.txt
efi-stub.txt doc: Fix trivial spelling mistake in efi-stub.txt 2013-12-19 15:09:14 +01:00
eisa.txt
email-clients.txt doc: fix some typos 2013-12-02 14:48:28 +01:00
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt gcov: compile specific gcov implementation based on gcc version 2013-11-13 12:09:34 +09:00
highuid.txt
HOWTO Documentation: HOWTO: Update broken links to tpp 2013-12-10 23:09:08 -08:00
hw_random.txt hwrng: Fix a wrong comment in Documentation/hw_random.txt 2013-03-10 18:16:36 +08:00
hwspinlock.txt doc: documentation/hwspinlock.txt fix typo 2013-08-27 10:46:02 +02:00
init.txt
initrd.txt
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 doc: fix some typos 2013-12-02 14:48:28 +01:00
iostats.txt iostats.txt: add easy-to-find description for field 6 2013-04-29 15:18:50 +02:00
IPMI.txt ipmi: add options to disable openfirmware and PCI scanning 2013-02-27 19:10:21 -08:00
IRQ-affinity.txt doc: fix a typo about irq affinity 2013-08-20 12:59:18 +02:00
IRQ-domain.txt doc: fix some typos 2013-12-02 14:48:28 +01:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt kernel-doc: Update references to SGML to refs to XML instead. 2013-05-28 12:02:11 +02:00
kernel-docs.txt
kernel-parameters.txt Bug-fixes: 2014-01-27 08:17:09 -08:00
kernel-per-CPU-kthreads.txt kthread: Add pointer to vmstat-avoidance patch 2013-09-25 06:49:46 -07:00
kmemcheck.txt Documentation/kmemcheck: update kmemcheck documentation 2013-08-27 10:47:05 +02:00
kmemleak.txt
kobject.txt kobject: remove kset from sysfs immediately in kset_unregister() 2013-12-07 21:20:11 -08:00
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 lockstat: Report avg wait and hold times 2013-10-09 08:19:08 +02:00
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
ManagementStyle
md.txt doc: fix some typos in documentations 2013-12-02 14:45:19 +01:00
media-framework.txt Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media 2013-07-13 12:09:57 -07:00
memory-barriers.txt locking/doc: Rename LOCK/UNLOCK to ACQUIRE/RELEASE 2014-01-12 10:37:13 +01:00
memory-hotplug.txt Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-09-06 09:36:28 -07:00
module-signing.txt Add Documentation/module-signing.txt file 2013-12-13 15:59:11 +00:00
mono.txt
mutex-design.txt locking/doc: Update references to kernel/mutex.c 2013-11-11 12:41:33 +01:00
nommu-mmap.txt
numastat.txt
oops-tracing.txt
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt percpu-rw-semaphore: fix documentation typos 2012-09-26 19:56:15 +02:00
phy.txt drivers: phy: add generic PHY framework 2013-09-27 17:35:41 -07:00
pi-futex.txt
pinctrl.txt pinctrl: Fix some typos and grammar issues in the documentation 2014-01-15 13:59:50 +01:00
pnp.txt
preempt-locking.txt
printk-formats.txt vsprintf: add %pad extension for dma_addr_t use 2014-01-23 16:36:56 -08:00
pwm.txt Documentation/pwm: Fix trivial typos 2013-10-24 10:51:33 +02:00
ramoops.txt
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 doc: fix some typos in documentations 2013-12-02 14:45:19 +01:00
robust-futex-ABI.txt Documentation/robust-futex-API: Count properly to 4 2013-11-30 14:08:28 +01:00
robust-futexes.txt
rpmsg.txt Documentation: remove __dev* attributes. 2013-01-03 15:57:16 -08:00
rt-mutex-design.txt doc: fix some typos in documentations 2013-12-02 14:45:19 +01:00
rt-mutex.txt
rtc.txt rtc: add ability to push out an existing wakealarm using sysfs 2013-07-03 16:07:54 -07:00
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 sched: Rename sched.c as sched/core.c in comments and Documentation 2013-06-19 12:58:42 +02:00
stable_api_nonsense.txt
stable_kernel_rules.txt
static-keys.txt doc: fix some typos in documentations 2013-12-02 14:45:19 +01:00
SubmitChecklist Finally eradicate CONFIG_HOTPLUG 2013-06-03 14:20:18 -07:00
SubmittingDrivers
SubmittingPatches Documentation/SubmittingPatches: Request summaries for commit references 2013-08-20 12:58:15 +02:00
svga.txt
sysfs-rules.txt doc: Fix typo in doucmentations 2013-07-25 12:34:15 +02:00
sysrq.txt sysrq: Allow magic SysRq key functions to be disabled through Kconfig 2013-10-16 13:01:44 -07:00
this_cpu_ops.txt percpu: add documentation on this_cpu operations 2013-04-04 10:24:53 -07:00
unaligned-memory-access.txt ether_addr_equal: Optimize implementation, remove unused compare_ether_addr 2013-12-06 16:37:43 -05:00
unicode.txt
unshare.txt
vfio.txt vfio: fix documentation 2013-09-05 16:36:21 -06:00
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt VME: Rename vme_slot_get to avoid confusion with reference counting 2013-12-03 11:15:58 -08:00
volatile-considered-harmful.txt
workqueue.txt workqueue: Correct/Drop references to gcwq in Documentation 2013-08-21 10:32:09 -04:00
ww-mutex-design.txt mutex: Add support for wound/wait style locks 2013-06-26 12:10:56 +02:00
xz.txt
zorro.txt zorro/UAPI: Disintegrate include/linux/zorro*.h 2013-11-26 11:09:08 +01:00