mm: batch-free pcp list if possible
free_pcppages_bulk() frees pages from pcp lists in a round-robin fashion
by keeping batch_free counter. But it doesn't need to spin if there is
only one non-empty list. This can be checked by batch_free ==
MIGRATE_PCPTYPES.
[akpm@linux-foundation.org: fix comment]
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 36a168e..426056a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -614,6 +614,10 @@
list = &pcp->lists[migratetype];
} while (list_empty(list));
+ /* This is the only non-empty list. Free them all. */
+ if (batch_free == MIGRATE_PCPTYPES)
+ batch_free = to_free;
+
do {
page = list_entry(list->prev, struct page, lru);
/* must delete as __free_one_page list manipulates */