zram: add set_max_streams knob
authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Mon, 7 Apr 2014 22:38:15 +0000 (15:38 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 7 Apr 2014 23:36:01 +0000 (16:36 -0700)
commitfe8eb122c82b2049c460fc6df6e8583a2f935cff
treebb01a02e6c451d96f379846195346bfde70baba7
parentbeca3ec71fe5490ee9237dc42400f50402baf83e
zram: add set_max_streams knob

This patch allows to change max_comp_streams on initialised zcomp.

Introduce zcomp set_max_streams() knob, zcomp_strm_multi_set_max_streams()
and zcomp_strm_single_set_max_streams() callbacks to change streams limit
for zcomp_strm_multi and zcomp_strm_single, accordingly.  set_max_streams
for single steam zcomp does nothing.

If user has lowered the limit, then zcomp_strm_multi_set_max_streams()
attempts to immediately free extra streams (as much as it can, depending
on idle streams availability).

Note, this patch does not allow to change stream 'policy' from single to
multi stream (or vice versa) on already initialised compression backend.

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>
drivers/block/zram/zcomp.c
drivers/block/zram/zcomp.h
drivers/block/zram/zram_drv.c