tree d489fff3885bb7c4df0eebd2f074a398420740e6
parent d179e84ba5da1d0024087d1759a2938817a00f3f
author Mel Gorman <mgorman@suse.de> 1308175732 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1308193442 -0700

mm: compaction: abort compaction if too many pages are isolated and caller is asynchronous V2

Asynchronous compaction is used when promoting to huge pages.  This is all
very nice but if there are a number of processes in compacting memory, a
large number of pages can be isolated.  An "asynchronous" process can
stall for long periods of time as a result with a user reporting that
firefox can stall for 10s of seconds.  This patch aborts asynchronous
compaction if too many pages are isolated as it's better to fail a
hugepage promotion than stall a process.

[minchan.kim@gmail.com: return COMPACT_PARTIAL for abort]
Reported-and-tested-by: Ury Stankevich <urykhy@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>