Hello, This patch set tweaks compaction and makes it possible to trigger pool compaction automatically when system is getting low on memory. zsmalloc in some cases can suffer from a notable fragmentation and compaction can release some considerable amount of memory. The problem here is that currently we fully rely on user space to perform compaction when needed. However, performing zsmalloc compaction is not always an obvious thing to do. For example, suppose we have a `idle' fragmented (compaction was never performed) zram device and system is getting low on memory due to some 3rd party user processes (gcc LTO, or firefox, etc.). It's quite unlikely that user space will issue zpool compaction in this case. Besides, user space cannot tell for sure how badly pool is fragmented; however, this info is known to zsmalloc and, hence, to a shrinker. v4: address review notes (Minchan) -- do not abort __zs_compact() quickly (Minchan) -- switch zsmalloc compaction to operate in terms of freed pages -- micro-optimize zs_can_compact() (Minchan) v3: -- drop almost_empty waterline adjustment patch (Minchan) -- do not hold class->lock for the entire compaction period (Minchan) v2: -- use a slab shrinker instead of triggering compaction from zs_free (Minchan) Sergey Senozhatsky (7): zsmalloc: drop unused variable `nr_to_migrate' zsmalloc: always keep per-class stats zsmalloc: introduce zs_can_compact() function zsmalloc: cosmetic compaction code adjustments zsmalloc/zram: store compaction stats in zspool zsmalloc: account the number of compacted pages zsmalloc: register a shrinker to trigger auto-compaction Documentation/blockdev/zram.txt | 3 +- drivers/block/zram/zram_drv.c | 12 +-- drivers/block/zram/zram_drv.h | 1 - include/linux/zsmalloc.h | 1 + mm/zsmalloc.c | 215 +++++++++++++++++++++++++++------------- 5 files changed, 154 insertions(+), 78 deletions(-) -- 2.5.0.rc0.3.g912bd49 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>