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mm/page_alloc.c: remove unlikely() from the current_order test 

In __rmqueue_fallback(), current_order loops down from MAX_ORDER - 1 to
the order passed.  MAX_ORDER is typically 11 and pageblock_order is
typically 9 on x86.  Integer division truncates, so pageblock_order / 2
is 4.  For the first eight iterations, it's guaranteed that
current_order >= pageblock_order / 2 if it even gets that far!

So just remove the unlikely(), it's completely bogus.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Suggested-by: David Rientjes <rientjes@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Zhang Yanfei 2013-07-08 16:00:08 -07:00 committed by Linus Torvalds
parent b21fbccd4b
commit 345606d429
1 changed files with 1 additions and 1 deletions
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2
mm/page_alloc.c
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@ -1046,7 +1046,7 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
* MIGRATE_CMA areas.
*/
if (!is_migrate_cma(migratetype) &&
(unlikely(current_order >= pageblock_order / 2) ||
(current_order >= pageblock_order / 2 ||
start_migratetype == MIGRATE_RECLAIMABLE ||
page_group_by_mobility_disabled)) {
int pages;