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 <>
Acked-by: default avatarVlastimil Babka <>
Cc: Mel Gorman <>
Cc: Rik van Riel <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
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,
/* Recheck this is a suitable migration target under lock */
if (!strict && !suitable_migration_target(page))
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))
/* Recheck this is a buddy page under lock */
if (!PageBuddy(page))
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment