[rh7,08/25] ms/mm/compaction: do not call suitable_migration_target() on every page

Submitted by Andrey Ryabinin on Jan. 24, 2018, 12:14 p.m.


Message ID 20180124121503.26930-9-aryabinin@virtuozzo.com
State New
Series "compaction related stable backports."
Headers show

Commit Message

Andrey Ryabinin Jan. 24, 2018, 12:14 p.m.
From: Joonsoo Kim <iamjoonsoo.kim@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.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 01ead5340bcf5f3a1cd2452c75516d0ef4d908d7)
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
 mm/compaction.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

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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,
 		/* 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))