mm/page_alloc: remove mistaken page == NULL check in rmqueue

If a page allocation fails, the ZONE_BOOSTER_WATERMARK should be tested,
cleared and kswapd woken whether the allocation attempt was via the PCP or
directly via the buddy list.

Remove the page == NULL so the ZONE_BOOSTED_WATERMARK bit is checked
unconditionally.  As it is unlikely that ZONE_BOOSTED_WATERMARK is set,
mark the branch accordingly.

Link: https://lkml.kernel.org/r/20220624125423.6126-5-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a384c3887ee7af00eb4c68684f7c3249e4b6e9fb..026c9437456c419191779d92a57d17bbb1aa6fcd 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3781,12 +3781,10 @@ 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));
        }