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authorYisheng Xie <xieyisheng1@huawei.com>2017-05-03 14:53:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-03 15:52:09 -0700
commit1ef36db2a96f23ac0a278d498072ef7193c8b8f2 (patch)
tree8422079b17f79c192197cbdd16a968e5dfaba6ab
parent60a7a88dbb9fc9adcca78a10a3ecf36966b5a45c (diff)
downloadlinux-1ef36db2a96f23ac0a278d498072ef7193c8b8f2.tar.bz2
mm/compaction: ignore block suitable after check large free page
By reviewing code, I find that if the migrate target is a large free page and we ignore suitable, it may splite large target free page into smaller block which is not good for defrag. So move the ignore block suitable after check large free page. As Vlastimil pointed out in RFC version that this patch is just based on logical analyses which might be better for future-proofing the function and it is most likely won't have any visible effect right now, for direct compaction shouldn't have to be called if there's a >=pageblock_order page already available. Link: http://lkml.kernel.org/r/1489490743-5364-1-git-send-email-xieyisheng1@huawei.com Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: David Rientjes <rientjes@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/compaction.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index 81e1eaa2a2cf..09c5282ebdd2 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -992,9 +992,6 @@ isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn,
static bool suitable_migration_target(struct compact_control *cc,
struct page *page)
{
- if (cc->ignore_block_suitable)
- return true;
-
/* If the page is a large free page, then disallow migration */
if (PageBuddy(page)) {
/*
@@ -1006,6 +1003,9 @@ static bool suitable_migration_target(struct compact_control *cc,
return false;
}
+ if (cc->ignore_block_suitable)
+ return true;
+
/* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
if (migrate_async_suitable(get_pageblock_migratetype(page)))
return true;