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vmscan: only defer compaction for failed order and higher

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Currently a failed order-9 (transparent hugepage) compaction can lead to
memory compaction being temporarily disabled for a memory zone.  Even if
we only need compaction for an order 2 allocation, eg.  for jumbo frames
networking.

The fix is relatively straightforward: keep track of the highest order at
which compaction is succeeding, and only defer compaction for orders at
which compaction is failing.

Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rik van Riel
2012-03-21 16:33:52 -07:00
committed by Linus Torvalds
parent 7be62de99a
commit aff622495c
5 changed files with 27 additions and 8 deletions
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6
mm/page_alloc.c
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@@ -1990,7 +1990,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
if (!order)
return NULL;
if (compaction_deferred(preferred_zone)) {
if (compaction_deferred(preferred_zone, order)) {
*deferred_compaction = true;
return NULL;
}
@@ -2012,6 +2012,8 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
if (page) {
preferred_zone->compact_considered = 0;
preferred_zone->compact_defer_shift = 0;
if (order >= preferred_zone->compact_order_failed)
preferred_zone->compact_order_failed = order + 1;
count_vm_event(COMPACTSUCCESS);
return page;
}
@@ -2028,7 +2030,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
* defer if the failure was a sync compaction failure.
*/
if (sync_migration)
defer_compaction(preferred_zone);
defer_compaction(preferred_zone, order);
cond_resched();
}