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authorWei Xu <weixugc@google.com>2024-10-14 22:12:11 +0000
committerAndrew Morton <akpm@linux-foundation.org>2024-10-17 00:28:12 -0700
commitb130ba4a6259f6b64d8af15e9e7ab1e912bcb7ad (patch)
treec5521d7c9406d3da8392096a592ebeacd665436b /mm
parent7528c4fb1237512ee18049f852f014eba80bbe8d (diff)
mm/mglru: only clear kswapd_failures if reclaimable
lru_gen_shrink_node() unconditionally clears kswapd_failures, which can prevent kswapd from sleeping and cause 100% kswapd cpu usage even when kswapd repeatedly fails to make progress in reclaim. Only clear kswap_failures in lru_gen_shrink_node() if reclaim makes some progress, similar to shrink_node(). I happened to run into this problem in one of my tests recently. It requires a combination of several conditions: The allocator needs to allocate a right amount of pages such that it can wake up kswapd without itself being OOM killed; there is no memory for kswapd to reclaim (My test disables swap and cleans page cache first); no other process frees enough memory at the same time. Link: https://lkml.kernel.org/r/20241014221211.832591-1-weixugc@google.com Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists") Signed-off-by: Wei Xu <weixugc@google.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: Jan Alexander Steffens <heftig@archlinux.org> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/vmscan.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 749cdc110c74..eb4e8440c507 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4963,8 +4963,8 @@ static void lru_gen_shrink_node(struct pglist_data *pgdat, struct scan_control *
blk_finish_plug(&plug);
done:
- /* kswapd should never fail */
- pgdat->kswapd_failures = 0;
+ if (sc->nr_reclaimed > reclaimed)
+ pgdat->kswapd_failures = 0;
}
/******************************************************************************