Messages in this thread Patch in this message |  | | From | Joonsoo Kim <> | Subject | [PATCH v2 2/5] mm/compaction: do not call suitable_migration_target() on every page | Date | Fri, 14 Feb 2014 15:54:00 +0900 |
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suitable_migration_target() checks that pageblock is suitable for migration target. In isolate_freepages_block(), it is called on every page and this is inefficient. So make it called once per pageblock.
suitable_migration_target() also checks if page is highorder or not, but it's criteria for highorder is pageblock order. So calling it once within pageblock range has no problem.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
diff --git a/mm/compaction.c b/mm/compaction.c index bbe1260..0d821a2 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -245,6 +245,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, unsigned long nr_strict_required = end_pfn - blockpfn; unsigned long flags; bool locked = false; + bool checked_pageblock = false; cursor = pfn_to_page(blockpfn); @@ -275,8 +276,16 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, break; /* Recheck this is a suitable migration target under lock */ - if (!strict && !suitable_migration_target(page)) - break; + if (!strict && !checked_pageblock) { + /* + * We need to check suitability of pageblock only once + * and this isolate_freepages_block() is called with + * pageblock range, so just check once is sufficient. + */ + checked_pageblock = true; + if (!suitable_migration_target(page)) + break; + } /* Recheck this is a buddy page under lock */ if (!PageBuddy(page)) -- 1.7.9.5
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