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android_kernel_google_msm/mm
Minchan Kim e92c074f5d UPSTREAM: zsmalloc: decouple handle and object
(cherry-pick from commit 2e40e163a25af3bd35d128d3e2e005916de5cce6)

Recently, we started to use zram heavily and some of issues
popped.

1) external fragmentation

I got a report from Juneho Choi that fork failed although there are plenty
of free pages in the system.  His investigation revealed zram is one of
the culprit to make heavy fragmentation so there was no more contiguous
16K page for pgd to fork in the ARM.

2) non-movable pages

Other problem of zram now is that inherently, user want to use zram as
swap in small memory system so they use zRAM with CMA to use memory
efficiently.  However, unfortunately, it doesn't work well because zRAM
cannot use CMA's movable pages unless it doesn't support compaction.  I
got several reports about that OOM happened with zram although there are
lots of swap space and free space in CMA area.

3) internal fragmentation

zRAM has started support memory limitation feature to limit memory usage
and I sent a patchset(https://lkml.org/lkml/2014/9/21/148) for VM to be
harmonized with zram-swap to stop anonymous page reclaim if zram consumed
memory up to the limit although there are free space on the swap.  One
problem for that direction is zram has no way to know any hole in memory
space zsmalloc allocated by internal fragmentation so zram would regard
swap is full although there are free space in zsmalloc.  For solving the
issue, zram want to trigger compaction of zsmalloc before it decides full
or not.

This patchset is first step to support above issues.  For that, it adds
indirect layer between handle and object location and supports manual
compaction to solve 3th problem first of all.

After this patchset got merged, next step is to make VM aware of zsmalloc
compaction so that generic compaction will move zsmalloced-pages
automatically in runtime.

In my imaginary experiment(ie, high compress ratio data with heavy swap
in/out on 8G zram-swap), data is as follows,

Before =
zram allocated object :      60212066 bytes
zram total used:     140103680 bytes
ratio:         42.98 percent
MemFree:          840192 kB

Compaction

After =
frag ratio after compaction
zram allocated object :      60212066 bytes
zram total used:      76185600 bytes
ratio:         79.03 percent
MemFree:          901932 kB

Juneho reported below in his real platform with small aging.
So, I think the benefit would be bigger in real aging system
for a long time.

- frag_ratio increased 3% (ie, higher is better)
- memfree increased about 6MB
- In buddy info, Normal 2^3: 4, 2^2: 1: 2^1 increased, Highmem: 2^1 21 increased

frag ratio after swap fragment
used :        156677 kbytes
total:        166092 kbytes
frag_ratio :  94
meminfo before compaction
MemFree:           83724 kB
Node 0, zone   Normal  13642   1364     57     10     61     17      9      5      4      0      0
Node 0, zone  HighMem    425     29      1      0      0      0      0      0      0      0      0

num_migrated :  23630
compaction done

frag ratio after compaction
used :        156673 kbytes
total:        160564 kbytes
frag_ratio :  97
meminfo after compaction
MemFree:           89060 kB
Node 0, zone   Normal  14076   1544     67     14     61     17      9      5      4      0      0
Node 0, zone  HighMem    863     50      1      0      0      0      0      0      0      0      0

This patchset adds more logics(about 480 lines) in zsmalloc but when I
tested heavy swapin/out program, the regression for swapin/out speed is
marginal because most of overheads were caused by compress/decompress and
other MM reclaim stuff.

This patch (of 7):

Currently, handle of zsmalloc encodes object's location directly so it
makes support of migration hard.

This patch decouples handle and object via adding indirect layer.  For
that, it allocates handle dynamically and returns it to user.  The handle
is the address allocated by slab allocation so it's unique and we could
keep object's location in the memory space allocated for handle.

With it, we can change object's position without changing handle itself.

Bug: 25951511

Change-Id: Id50a98341f63c4e1bb39589ca992661486469dca
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Juneho Choi <juno.choi@lge.com>
Cc: Gunho Lee <gunho.lee@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-01 21:27:09 +03:00
..
backing-dev.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
bootmem.c mm: sparse: fix usemap allocation above node descriptor section 2016-10-29 23:12:12 +08:00
bounce.c
cleancache.c
compaction.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
debug-pagealloc.c
dmapool.c mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls 2012-12-17 10:37:44 -08:00
fadvise.c mm/fadvise.c: drain all pagevecs if POSIX_FADV_DONTNEED fails to discard all pages 2013-02-28 06:59:01 -08:00
failslab.c
filemap.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
filemap_xip.c fs: introduce inode operation ->update_time 2015-07-13 11:17:49 -07:00
fremap.c
highmem.c mm: highmem: don't treat PKMAP_ADDR(LAST_PKMAP) as a highmem address 2014-06-11 12:04:22 -07:00
huge_memory.c mm, thp: fix collapsing of hugepages on madvise 2015-02-02 17:05:07 +08:00
hugetlb.c Fix incomplete backport of commit 0f792cf949a0 2016-10-26 23:15:44 +08:00
hwpoison-inject.c
init-mm.c
internal.h Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
Kconfig BACKPORT: mm/zsmalloc: add statistics support 2018-01-01 21:27:09 +03:00
Kconfig.debug
kmemcheck.c
kmemleak-test.c
kmemleak.c mm: kmemleak: allow safe memory scanning during kmemleak disabling 2015-10-22 09:20:06 +08:00
ksm.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
maccess.c
madvise.c mm: add a field to store names for private anonymous memory 2013-10-11 10:02:06 -07:00
Makefile BACKPORT: mm/zpool: implement common zpool api to zbud/zsmalloc 2018-01-01 21:27:00 +03:00
memblock.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
memcontrol.c memcg: fix multiple large threshold notifications 2013-09-26 17:15:50 -07:00
memory-failure.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
memory.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
memory_hotplug.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
mempolicy.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
mempool.c
migrate.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
mincore.c
mlock.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
mm_init.c
mmap.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
mmu_context.c
mmu_notifier.c mm: mmu_notifier: re-fix freed page still mapped in secondary MMU 2013-06-07 12:49:25 -07:00
mmzone.c
mprotect.c mm: add a field to store names for private anonymous memory 2013-10-11 10:02:06 -07:00
mremap.c
msync.c
nobootmem.c memblock: free allocated memblock_reserved_regions later 2012-07-16 09:04:45 -07:00
nommu.c mm/nommu.c: fix arithmetic overflow in __vm_enough_memory() 2015-06-19 11:40:15 +08:00
oom_kill.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
page-writeback.c mm: fix calculation of dirtyable memory 2016-10-29 23:12:16 +08:00
page_alloc.c mm/page_alloc.c: use '__paginginit' instead of '__init' 2017-12-27 17:13:39 +03:00
page_cgroup.c cgroup/kmemleak: add kmemleak_free() for cgroup deallocations. 2015-02-02 17:05:07 +08:00
page_io.c
page_isolation.c mm: page_isolation: MIGRATE_CMA isolation functions added 2013-02-27 18:14:02 -08:00
pagewalk.c mm/pagewalk.c: walk_page_range should avoid VM_PFNMAP areas 2013-06-07 12:49:28 -07:00
percpu-km.c
percpu-vm.c percpu: perform tlb flush after pcpu_map_pages() failure 2014-12-01 18:02:23 +08:00
percpu.c Revert "percpu: free percpu allocation info for uniprocessor system" 2015-02-02 17:04:38 +08:00
pgtable-generic.c
prio_tree.c
process_vm_access.c Fix: compat_rw_copy_check_uvector() misuse in aio, readv, writev, and security keys 2013-03-14 11:29:51 -07:00
quicklist.c
readahead.c mm: change initial readahead window size calculation 2016-10-29 23:12:18 +08:00
rmap.c mm: fix anon_vma->degree underflow in anon_vma endless growing prevention 2015-04-14 17:34:04 +08:00
shmem.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
slab.c cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags 2014-12-01 18:02:38 +08:00
slob.c
slub.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
sparse-vmemmap.c
sparse.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
swap.c mm: hugetlbfs: fix hugetlbfs optimization 2014-02-06 11:05:46 -08:00
swap_state.c swap: avoid read_swap_cache_async() race to deadlock while waiting on discard I/O completion 2013-06-20 11:58:45 -07:00
swapfile.c BACKPORT: mm: /proc/pid/smaps:: show proportional swap share of the mapping 2017-12-27 22:48:40 +03:00
thrash.c
truncate.c mm: Remove false WARN_ON from pagecache_isize_extended() 2015-02-02 17:05:24 +08:00
util.c nick kvfree() from apparmor 2014-11-18 15:13:23 -08:00
vmalloc.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
vmscan.c mm: vmscan: clear kswapd's special reclaim powers before exiting 2016-10-29 23:12:33 +08:00
vmstat.c Merge remote-tracking branch 'stable/linux-3.4.y' into lineage-15.1 2017-12-27 17:13:15 +03:00
zpool.c BACKPORT: mm/zpool: add name argument to create zpool 2018-01-01 21:27:09 +03:00
zsmalloc.c UPSTREAM: zsmalloc: decouple handle and object 2018-01-01 21:27:09 +03:00