Commit 01ead534 authored by Joonsoo Kim's avatar Joonsoo Kim Committed by Linus Torvalds

mm/compaction: do not call suitable_migration_target() on every page

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: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7d348b9e
......@@ -244,6 +244,7 @@ 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);
......@@ -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))
......
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