diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_alloc.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e8153eca7..45fc870c9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1311,16 +1311,19 @@ static int preferred_mt = MIGRATE_MOVABLE; #endif /* - * If breaking a large block of pages, move all free pages to the preferred - * allocation list. If falling back for a reclaimable kernel allocation, be - * more aggressive about taking ownership of free pages. + * When we are falling back to another migratetype during allocation, try to + * steal extra free pages from the same pageblocks to satisfy further + * allocations, instead of polluting multiple pageblocks. * - * On the other hand, never change migration type of MIGRATE_CMA pageblocks - * nor move CMA pages to different free lists. We don't want unmovable pages - * to be allocated from MIGRATE_CMA areas. + * If we are stealing a relatively large buddy page, it is likely there will + * be more free pages in the pageblock, so try to steal them all. For + * reclaimable and unmovable allocations, we steal regardless of page size, + * as fragmentation caused by those allocations polluting movable pageblocks + * is worse than movable allocations stealing from unmovable and reclaimable + * pageblocks. * - * Returns the new migratetype of the pageblock (or the same old migratetype - * if it was unchanged). + * If we claim more than half of the pageblock, change pageblock's migratetype + * as well. */ static int try_to_steal_freepages(struct zone *zone, struct page *page, int start_type, int fallback_type) @@ -1338,6 +1341,7 @@ static int try_to_steal_freepages(struct zone *zone, struct page *page, if (current_order >= pageblock_order / 2 || start_type == MIGRATE_RECLAIMABLE || + start_type == MIGRATE_UNMOVABLE || page_group_by_mobility_disabled) { int pages; |