mm: compaction: make isolate_lru_page() filter-aware again

commit c82449352854ff09e43062246af86bdeb628f0c3 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.  This
had to be partially reverted because some dirty pages can be migrated by
compaction without blocking.

This patch updates "mm: compaction: make isolate_lru_page" by skipping
over pages that migration has no possibility of migrating to minimise LRU

Signed-off-by: Mel Gorman <>
Reviewed-by: Rik van Riel<>
Cc: Andrea Arcangeli <>
Reviewed-by: Minchan Kim <>
Cc: Dave Jones <>
Cc: Jan Kara <>
Cc: Andy Isaacson <>
Cc: Nai Xia <>
Cc: Johannes Weiner <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
Signed-off-by: Greg Kroah-Hartman <>
3 files changed