[RFC PATCH 19/26] mm: compaction: drop redundant watermark check in compaction_zonelist_suitable()

Johannes Weiner
2023-04-18T19:15:08Z

should_compact_retry() is called after direct reclaim and compaction
have failed to produce a page, to check if there is still enough
compactable memory to warrant continuing. If there aren't, one last
attempt at the freelists happens in __alloc_pages_may_oom(). The
watermark check in should_compact_retry() is not necessary. Kill it.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
mm/compaction.c | 7 -------
1 file changed, 7 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 0aa2a0a192dc..52103545d58c 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2263,13 +2263,6 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
ac->highest_zoneidx, ac->nodemask) {
unsigned long available;
- unsigned long watermark;
-
- /* Allocation can already succeed, nothing to do */
- watermark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
- if (zone_watermark_ok(zone, order, watermark,
- ac->highest_zoneidx, alloc_flags))
- continue;

available = zone_page_state_snapshot(zone, NR_FREE_MOVABLE);
available += zone_page_state_snapshot(zone, NR_FREE_CMA_PAGES);
--
2.39.2