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| author | Chengming Zhou <zhouchengming@bytedance.com> | 2024-02-04 03:06:00 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-02-22 10:24:54 -0800 |
| commit | 0827a1fb143fae588cb6f5b9a97c405d6c2ddec9 (patch) | |
| tree | 76de3ff51d3ad34fbc26d8743134ce1b383d4fd9 /mm/swap_slots.c | |
| parent | f9c0f1c32cb568e16ef0676d8e7827a3ad443742 (diff) | |
| download | linux-0827a1fb143fae588cb6f5b9a97c405d6c2ddec9.tar.gz linux-0827a1fb143fae588cb6f5b9a97c405d6c2ddec9.tar.bz2 linux-0827a1fb143fae588cb6f5b9a97c405d6c2ddec9.zip | |
mm/zswap: invalidate zswap entry when swap entry free
During testing I found there are some times the zswap_writeback_entry()
return -ENOMEM, which is not we expected:
bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}'
@[-12]: 1563
@[0]: 277221
The reason is that __read_swap_cache_async() return NULL because
swapcache_prepare() failed. The reason is that we won't invalidate zswap
entry when swap entry freed to the per-cpu pool, these zswap entries are
still on the zswap tree and lru list.
This patch moves the invalidation ahead to when swap entry freed to the
per-cpu pool, since there is no any benefit to leave trashy zswap entry on
the tree and lru list.
With this patch:
bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}'
@[0]: 259744
Note: large folio can't have zswap entry for now, so don't bother
to add zswap entry invalidation in the large folio swap free path.
Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-2-99d4084260a0@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/swap_slots.c')
| -rw-r--r-- | mm/swap_slots.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/swap_slots.c b/mm/swap_slots.c index 0bec1f705f8e..90973ce7881d 100644 --- a/mm/swap_slots.c +++ b/mm/swap_slots.c @@ -273,6 +273,9 @@ void free_swap_slot(swp_entry_t entry) { struct swap_slots_cache *cache; + /* Large folio swap slot is not covered. */ + zswap_invalidate(entry); + cache = raw_cpu_ptr(&swp_slots); if (likely(use_swap_slot_cache && cache->slots_ret)) { spin_lock_irq(&cache->free_lock); |