mm, page_alloc: add unlikely macro to help compiler optimization
We rarely allocate a page with ALLOC_NO_WATERMARKS and it is used in slow path. For helping compiler optimization, add unlikely macro to ALLOC_NO_WATERMARKS checking. This patch doesn't have any effect now, because gcc already optimize this properly. But we cannot assume that gcc always does right and nobody re-evaluate if gcc do proper optimization with their change, for example, it is not optimized properly on v3.10. So adding compiler hint here is reasonable. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
1da6f0e1b3
commit
e66f097257
|
@ -1909,7 +1909,7 @@ zonelist_scan:
|
|||
!cpuset_zone_allowed_softwall(zone, gfp_mask))
|
||||
continue;
|
||||
BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
|
||||
if (alloc_flags & ALLOC_NO_WATERMARKS)
|
||||
if (unlikely(alloc_flags & ALLOC_NO_WATERMARKS))
|
||||
goto try_this_zone;
|
||||
/*
|
||||
* Distribute pages in proportion to the individual
|
||||
|
|
Loading…
Reference in a new issue