]> git.baikalelectronics.ru Git - kernel.git/commit
oom, trace: add compaction retry tracepoint
authorMichal Hocko <mhocko@suse.com>
Wed, 22 Feb 2017 23:42:03 +0000 (15:42 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 23 Feb 2017 00:41:27 +0000 (16:41 -0800)
commit36baafdd9b27c37f50326f4c5f910b06bb57a76c
treec57be762c29b20bba680e11303c890c9b49f605b
parent0274091ec4e32b43ad73a16112701c2c4518222e
oom, trace: add compaction retry tracepoint

Higher order requests oom debugging is currently quite hard.  We do have
some compaction points which can tell us how the compaction is operating
but there is no trace point to tell us about compaction retry logic.
This patch adds a one which will have the following format

            bash-3126  [001] ....  1498.220001: compact_retry: order=9 priority=COMPACT_PRIO_SYNC_LIGHT compaction_result=withdrawn retries=0 max_retries=16 should_retry=0

we can see that the order 9 request is not retried even though we are in
the highest compaction priority mode becase the last compaction attempt
was withdrawn.  This means that compaction_zonelist_suitable must have
returned false and there is no suitable zone to compact for this request
and so no need to retry further.

another example would be
           <...>-3137  [001] ....    81.501689: compact_retry: order=9 priority=COMPACT_PRIO_SYNC_LIGHT compaction_result=failed retries=0 max_retries=16 should_retry=0

in this case the order-9 compaction failed to find any suitable block.
We do not retry anymore because this is a costly request and those do
not go below COMPACT_PRIO_SYNC_LIGHT priority.

Link: http://lkml.kernel.org/r/20161220130135.15719-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/trace/events/mmflags.h
include/trace/events/oom.h
mm/page_alloc.c