From: Joonsoo Kim <iamjoonsoo....@lge.com> 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....@lge.com> Acked-by: Vlastimil Babka <vba...@suse.cz> Cc: Mel Gorman <mgor...@suse.de> Cc: Rik van Riel <r...@redhat.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> (cherry picked from commit 01ead5340bcf5f3a1cd2452c75516d0ef4d908d7) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- mm/compaction.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 1faade458d38..c29883fe146d 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -247,6 +247,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, struct page *cursor, *valid_page = NULL; unsigned long flags; bool locked = false; + bool checked_pageblock = false; cursor = pfn_to_page(blockpfn); @@ -278,8 +279,16 @@ 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)) -- 2.13.6 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel