From b49547ade38a63ff39c9fbc53fb38622cb63854a Mon Sep 17 00:00:00 2001 From: Chengming Zhou Date: Sun, 4 Feb 2024 03:06:01 +0000 Subject: [PATCH] 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 Acked-by: Johannes Weiner Acked-by: Nhat Pham Reviewed-by: Yosry Ahmed Signed-off-by: Andrew Morton --- include/linux/list_lru.h | 2 ++ mm/list_lru.c | 3 +++ mm/zswap.c | 4 +++- 3 files changed, 8 insertions(+), 1 deletion(-) diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h index f2882a820690..792b67ceb631 100644 --- a/include/linux/list_lru.h +++ b/include/linux/list_lru.h @@ -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 { diff --git a/mm/list_lru.c b/mm/list_lru.c index 61f3b6b1134f..3fd64736bc45 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -243,6 +243,9 @@ restart: */ assert_spin_locked(&nlru->lock); goto restart; + case LRU_STOP: + assert_spin_locked(&nlru->lock); + goto out; default: BUG(); } diff --git a/mm/zswap.c b/mm/zswap.c index ef41a7bd81f2..f8a4ac389118 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -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++; }