zsmalloc: account the number of compacted pages
authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Tue, 8 Sep 2015 22:04:38 +0000 (15:04 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 8 Sep 2015 22:35:28 +0000 (15:35 -0700)
commit860c707dca155a56dfa115ddd6c00959296144a6
treee46b5110aa65f7b75ed8c8b6e5fa97367f10c05a
parent7d3f3938236b4bb878214e6791e76fd8409bdeee
zsmalloc: account the number of compacted pages

Compaction returns back to zram the number of migrated objects, which is
quite uninformative -- we have objects of different sizes so user space
cannot obtain any valuable data from that number.  Change compaction to
operate in terms of pages and return back to compaction issuer the
number of pages that were freed during compaction.  So from now on we
will export more meaningful value in zram<id>/mm_stat -- the number of
freed (compacted) pages.

This requires:
 (a) a rename of `num_migrated' to 'pages_compacted'
 (b) a internal API change -- return first_page's fullness_group from
     putback_zspage(), so we know when putback_zspage() did
     free_zspage().  It helps us to account compaction stats correctly.

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