mm/zswap: stop lru list shrinking when encounter warm region

When the shrinker encounter an existing folio in swap cache, it means we
are shrinking into the warmer region.  We should terminate shrinking if
we're in the dynamic shrinker context.

This patch add LRU_STOP to support this, to avoid overshrinking.

Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-3-99d4084260a0@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Chengming Zhou 2024-02-04 03:06:01 +00:00 committed by Andrew Morton
parent 0827a1fb14
commit b49547ade3
3 changed files with 8 additions and 1 deletions

View File

@ -24,6 +24,8 @@ enum lru_status {
LRU_SKIP, /* item cannot be locked, skip */
LRU_RETRY, /* item not freeable. May drop the lock
internally, but has to return locked. */
LRU_STOP, /* stop lru list walking. May drop the lock
internally, but has to return locked. */
};
struct list_lru_one {

View File

@ -243,6 +243,9 @@ restart:
*/
assert_spin_locked(&nlru->lock);
goto restart;
case LRU_STOP:
assert_spin_locked(&nlru->lock);
goto out;
default:
BUG();
}

View File

@ -1315,8 +1315,10 @@ static enum lru_status shrink_memcg_cb(struct list_head *item, struct list_lru_o
* into the warmer region. We should terminate shrinking (if we're in the dynamic
* shrinker context).
*/
if (writeback_result == -EEXIST && encountered_page_in_swapcache)
if (writeback_result == -EEXIST && encountered_page_in_swapcache) {
ret = LRU_STOP;
*encountered_page_in_swapcache = true;
}
} else {
zswap_written_back_pages++;
}