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authorMel Gorman <mel@csn.ul.ie>2009-06-16 15:31:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-16 19:47:33 -0700
commit49255c619fbd482d704289b5eb2795f8e3b7ff2e (patch)
treeb1f36ca46bda7767fce12bc4a70360a68f7255ab /mm
parent11e33f6a55ed7847d9c8ffe185ef87faf7806abe (diff)
page allocator: move check for disabled anti-fragmentation out of fastpath
On low-memory systems, anti-fragmentation gets disabled as there is nothing it can do and it would just incur overhead shuffling pages between lists constantly. Currently the check is made in the free page fast path for every page. This patch moves it to a slow path. On machines with low memory, there will be small amount of additional overhead as pages get shuffled between lists but it should quickly settle. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_alloc.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 512bf9a618c..b09859629e9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -168,6 +168,10 @@ int page_group_by_mobility_disabled __read_mostly;
static void set_pageblock_migratetype(struct page *page, int migratetype)
{
+
+ if (unlikely(page_group_by_mobility_disabled))
+ migratetype = MIGRATE_UNMOVABLE;
+
set_pageblock_flags_group(page, (unsigned long)migratetype,
PB_migrate, PB_migrate_end);
}