From 6ea41c0c0aa37d87ef5dd0d14535d2e1e195cd83 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Wed, 29 Oct 2014 14:50:20 -0700 Subject: [PATCH] mm/compaction.c: avoid premature range skip in isolate_migratepages_range Commit edc2ca612496 ("mm, compaction: move pageblock checks up from isolate_migratepages_range()") commonizes isolate_migratepages variants and make them use isolate_migratepages_block(). isolate_migratepages_block() could stop the execution when enough pages are isolated, but, there is no code in isolate_migratepages_range() to handle this case. In the result, even if isolate_migratepages_block() returns prematurely without checking all pages in the range, isolate_migratepages_block() is called repeately on the following pageblock and some pages in the previous range are skipped to check. Then, CMA is failed frequently due to this fact. To fix this problem, this patch let isolate_migratepages_range() know the situation that enough pages are isolated and stop the isolation in that case. Note that isolate_migratepages() has no such problem, because, it always stops the isolation after just one call of isolate_migratepages_block(). Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka Cc: David Rientjes Cc: Minchan Kim Cc: Michal Nazarewicz Cc: Naoya Horiguchi Cc: Christoph Lameter Cc: Rik van Riel Cc: Mel Gorman Cc: Zhang Yanfei Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/compaction.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/compaction.c b/mm/compaction.c index edba18aed173..ec74cf0123ef 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -784,6 +784,9 @@ isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn, cc->nr_migratepages = 0; break; } + + if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) + break; } acct_isolated(cc->zone, cc); -- 2.20.1