zram: add lz4 algorithm backend

Introduce LZ4 compression backend and make it available for selection.
LZ4 support is optional and requires user to set ZRAM_LZ4_COMPRESS config
option. The default

zram: add lz4 algorithm backend

Introduce LZ4 compression backend and make it available for selection.
LZ4 support is optional and requires user to set ZRAM_LZ4_COMPRESS config
option. The default compression backend is LZO.

TEST

(x86_64, core i5, 2 cores + 2 hyperthreading, zram disk size 1G,
ext4 file system, 3 compression streams)

iozone -t 3 -R -r 16K -s 60M -I +Z

Test LZO LZ4
----------------------------------------------
Initial write 1642744.62 1317005.09
Rewrite 2498980.88 1800645.16
Read 3957026.38 5877043.75
Re-read 3950997.38 5861847.00
Reverse Read 2937114.56 5047384.00
Stride read 2948163.19 4929587.38
Random read 3292692.69 4880793.62
Mixed workload 1545602.62 3502940.38
Random write 2448039.75 1758786.25
Pwrite 1670051.03 1338329.69
Pread 2530682.00 5097177.62
Fwrite 3232085.62 3275942.56
Fread 6306880.25 6645271.12

So on my system LZ4 is slower in write-only tests, while it performs
better in read-only and mixed (reads + writes) tests.

Official LZ4 benchmarks available here http://code.google.com/p/lz4/
(linux kernel uses revision r90).

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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zram: use zcomp compressing backends

Do not perform direct LZO compress/decompress calls, initialise
and use zcomp LZO backend (single compression stream) instead.

[akpm@linux-foundation.org: resol

zram: use zcomp compressing backends

Do not perform direct LZO compress/decompress calls, initialise
and use zcomp LZO backend (single compression stream) instead.

[akpm@linux-foundation.org: resolve conflicts with zram-delete-zram_init_device-fix.patch]
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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Merge branch 'next' into for-linus

First round of input updates for 3.15.

Merge remote-tracking branch 'airlied/drm-next' into drm-intel-next

Conflicts:
drivers/gpu/drm/i915/Makefile

Makefile cleanup in drm-intel-next conflicts with a build-fix to move
intel_opregion un

Merge remote-tracking branch 'airlied/drm-next' into drm-intel-next

Conflicts:
drivers/gpu/drm/i915/Makefile

Makefile cleanup in drm-intel-next conflicts with a build-fix to move
intel_opregion under CONFIG_ACPI.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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Merge tag 'v3.14-rc6' into drm-intel-next-queued

Linux 3.14-rc6

I need the hdmi/dvi-dual link fixes in 3.14 to avoid ugly conflicts
when merging Ville's new hdmi cloning support into my -next tree

Merge tag 'v3.14-rc6' into drm-intel-next-queued

Linux 3.14-rc6

I need the hdmi/dvi-dual link fixes in 3.14 to avoid ugly conflicts
when merging Ville's new hdmi cloning support into my -next tree

Conflicts:
drivers/gpu/drm/i915/Makefile
drivers/gpu/drm/i915/intel_dp.c

Makefile cleanup conflicts with an acpi build fix, intel_dp.c is
trivial.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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Merge tag 'parse-val' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap into asoc-core

regmap: Add parse_val() API

This is useful for generic code built on top of regmap dealing with

Merge tag 'parse-val' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap into asoc-core

regmap: Add parse_val() API

This is useful for generic code built on top of regmap dealing with
blocks of data.

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Merge tag 'v3.14-rc4' into next

Merge with Linux 3.14-rc4 to bring devm_request_any_context_irq().

Merge tag 'xtensa-for-next-20140221-1' into for_next

Xtensa fixes for 3.14:
- allow booting xtfpga on boards with new uBoot and >128MBytes memory;
- drop nonexistent GPIO32 support from fsf variant;

Merge tag 'xtensa-for-next-20140221-1' into for_next

Xtensa fixes for 3.14:
- allow booting xtfpga on boards with new uBoot and >128MBytes memory;
- drop nonexistent GPIO32 support from fsf variant;
- don't select USE_GENERIC_SMP_HELPERS;
- enable common clock framework support, set up ethoc clock on xtfpga;
- wire up sched_setattr and sched_getattr syscalls.

Signed-off-by: Chris Zankel <chris@zankel.net>

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Merge branch 'master' into for-next

Merge remote-tracking branch 'wireless-next/master' into mac80211-next

Merge branch 'linus' into perf/core

Refresh the branch to a v3.14-rc base before queueing up new devel patches.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'efi-urgent' into x86/urgent

* Avoid WARN_ON() when mapping BGRT on Baytrail (EFI 32-bit).

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Merge remote-tracking branch 'wireless-next/master' into ath-next

Merge tag 'v3.14-rc1' into patchwork

Linus 3.14-rc1

* tag 'v3.14-rc1': (11781 commits)
Linus 3.14-rc1
hpfs: optimize quad buffer loading
hpfs: remember free space
parisc: add flexible mmap

Merge tag 'v3.14-rc1' into patchwork

Linus 3.14-rc1

* tag 'v3.14-rc1': (11781 commits)
Linus 3.14-rc1
hpfs: optimize quad buffer loading
hpfs: remember free space
parisc: add flexible mmap memory layout support
parisc: Make EWOULDBLOCK be equal to EAGAIN on parisc
parisc: convert uapi/asm/stat.h to use native types only
parisc: wire up sched_setattr and sched_getattr
parisc: fix cache-flushing
parisc/sti_console: prefer Linux fonts over built-in ROM fonts
hwmon: Fix SENSORS_TMP102 dependencies to eliminate build errors
hwmon: Fix SENSORS_LM75 dependencies to eliminate build errors
tools/power turbostat: introduce -s to dump counters
tools/power turbostat: remove unused command line option
afs: proc cells and rootcell are writeable
tile: remove compat_sys_lookup_dcookie declaration to fix compile error
Revert "PCI: Remove from bus_list and release resources in pci_release_dev()"
ARM: multi_v7_defconfig: remove redundant entries and re-enable TI_EDMA
ARM: multi_v7_defconfig: add mvebu drivers
clocksource: kona: Add basic use of external clock
drivers: bus: fix CCI driver kcalloc call parameters swap
...

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Merge branch 'linus' into sched/core, to resolve conflicts

Conflicts:
kernel/sysctl.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'linus' into core/locking

Refresh the topic.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'akpm' (patches from Andrew Morton)

Merge misc fixes from Andrew Morton:
"A few hotfixes and various leftovers which were awaiting other merges.

Mainly movement of zram into mm/"

*

Merge branch 'akpm' (patches from Andrew Morton)

Merge misc fixes from Andrew Morton:
"A few hotfixes and various leftovers which were awaiting other merges.

Mainly movement of zram into mm/"

* emailed patches fron Andrew Morton <akpm@linux-foundation.org>: (25 commits)
memcg: fix mutex not unlocked on memcg_create_kmem_cache fail path
Documentation/filesystems/vfs.txt: update file_operations documentation
mm, oom: base root bonus on current usage
mm: don't lose the SOFT_DIRTY flag on mprotect
mm/slub.c: fix page->_count corruption (again)
mm/mempolicy.c: fix mempolicy printing in numa_maps
zram: remove zram->lock in read path and change it with mutex
zram: remove workqueue for freeing removed pending slot
zram: introduce zram->tb_lock
zram: use atomic operation for stat
zram: remove unnecessary free
zram: delay pending free request in read path
zram: fix race between reset and flushing pending work
zsmalloc: add maintainers
zram: add zram maintainers
zsmalloc: add copyright
zram: add copyright
zram: remove old private project comment
zram: promote zram from staging
zsmalloc: move it under mm
...

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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 produc

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>

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