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| author | Wei Xu <weixugc@google.com> | 2024-10-14 22:12:11 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-10-22 15:46:21 +0200 |
| commit | a0035fc55554773b31dfa59b44b96c6588c4b41b (patch) | |
| tree | 16a79913deab8504e7bfd71b13921981170084b9 | |
| parent | 17396e32f975130b3e6251f024c8807d192e4c3e (diff) | |
| download | linux-a0035fc55554773b31dfa59b44b96c6588c4b41b.tar.gz linux-a0035fc55554773b31dfa59b44b96c6588c4b41b.tar.bz2 linux-a0035fc55554773b31dfa59b44b96c6588c4b41b.zip | |
mm/mglru: only clear kswapd_failures if reclaimable
commit b130ba4a6259f6b64d8af15e9e7ab1e912bcb7ad upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | mm/vmscan.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 81533bed0b46..3c91b86d59e9 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -5603,8 +5603,8 @@ 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; } /****************************************************************************** |