commit a77ebd333cd810d7b680d544be88c875131c2bd3 upstream. Stable note: Not tracked in Bugzilla. A fix aimed at preserving page aging information by reducing LRU list churning had the side-effect of reducing THP allocation success rates. This was part of a series to restore the success rates while preserving the reclaim fix. Commit [39deaf85: mm: compaction: make isolate_lru_page() filter-aware] noted that compaction does not migrate dirty or writeback pages and that is was meaningless to pick the page and re-add it to the LRU list. What was missed during review is that asynchronous migration moves dirty pages if their ->migratepage callback is migrate_page() because these can be moved without blocking. This potentially impacted hugepage allocation success rates by a factor depending on how many dirty pages are in the system. This patch partially reverts 39deaf85 to allow migration to isolate dirty pages again. This increases how much compaction disrupts the LRU but that is addressed later in the series. Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> Reviewed-by: Rik van Riel <riel@xxxxxxxxxx> Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx> --- mm/compaction.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 61e68a5..afdc416 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -371,9 +371,6 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, continue; } - if (!cc->sync) - mode |= ISOLATE_CLEAN; - /* Try isolate the page */ if (__isolate_lru_page(page, mode, 0) != 0) continue; -- 1.7.9.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>