The VM_BUG_ON check for a valid page can be avoided with a simple
change in the flow. The ZONE_BOOSTED_WATERMARK is unlikely in general
and even more unlikely if the page allocation failed so mark the
branch unlikely.
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4c1acf666056..dc0fdeb3795c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3765,17 +3765,18 @@ struct page *rmqueue(struct zone *preferred_zone,
page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags,
migratetype);
- if (unlikely(!page))
- return NULL;
out:
/* Separate test+clear to avoid unnecessary atomics */
- if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) {
+ if (unlikely(test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags))) {
clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
wakeup_kswapd(zone, 0, 0, zone_idx(zone));
}
- VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
+ if (unlikely(!page))
+ return NULL;
+
+ VM_BUG_ON_PAGE(bad_range(zone, page), page);
return page;
}
--
2.34.1
