There is no compact_defer_limit. It should be compact_defer_shift in use. and add compact_order_failed explanation. Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx --- include/linux/mmzone.h | 1 + mm/compaction.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index c4c37fd12104..592ef93ae64c 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -512,6 +512,7 @@ struct zone { * On compaction failure, 1<<compact_defer_shift compactions * are skipped before trying again. The number attempted since * last failure is tracked with compact_considered. + * compact_order_failed is the minimum compaction failed order. */ unsigned int compact_considered; unsigned int compact_defer_shift; diff --git a/mm/compaction.c b/mm/compaction.c index fd988b7e5f2b..48114f98e362 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -136,7 +136,7 @@ void __ClearPageMovable(struct page *page) /* * Compaction is deferred when compaction fails to result in a page - * allocation success. 1 << compact_defer_limit compactions are skipped up + * allocation success. compact_defer_shift++, compactions are skipped up * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT */ void defer_compaction(struct zone *zone, int order) -- 1.8.3.1