zsmalloc/zram: introduce zs_pool_stats api
authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Tue, 8 Sep 2015 22:04:35 +0000 (15:04 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 8 Sep 2015 22:35:28 +0000 (15:35 -0700)
commit7d3f3938236b4bb878214e6791e76fd8409bdeee
treea28c0a163b7a88ddf5f728331e8a7a87f5d8d209
parent0dc63d488a2a433a4a85d3908b3f195c4e6450d2
zsmalloc/zram: introduce zs_pool_stats api

`zs_compact_control' accounts the number of migrated objects but it has
a limited lifespan -- we lose it as soon as zs_compaction() returns back
to zram.  It worked fine, because (a) zram had it's own counter of
migrated objects and (b) only zram could trigger compaction.  However,
this does not work for automatic pool compaction (not issued by zram).
To account objects migrated during auto-compaction (issued by the
shrinker) we need to store this number in zs_pool.

Define a new `struct zs_pool_stats' structure to keep zs_pool's stats
there.  It provides only `num_migrated', as of this writing, but it
surely can be extended.

A new zsmalloc zs_pool_stats() symbol exports zs_pool's stats back to
caller.

Use zs_pool_stats() in zram and remove `num_migrated' from zram_stats.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Suggested-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/block/zram/zram_drv.c
drivers/block/zram/zram_drv.h
include/linux/zsmalloc.h
mm/zsmalloc.c