From b49547ade38a63ff39c9fbc53fb38622cb63854a Mon Sep 17 00:00:00 2001
From: Chengming Zhou <zhouchengming@bytedance.com>
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 <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>
---
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 f2882a8206902..792b67ceb631b 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 61f3b6b1134fb..3fd64736bc458 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -243,6 +243,9 @@ __list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx,
*/
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 ef41a7bd81f24..f8a4ac389118a 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++;
}
--
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