From: Yosry Ahmed <yosryahmed@google.com>
To: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Nhat Pham <nphamcs@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Chris Li <chriscli@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 1/3] mm/zswap: don't return LRU_SKIP if we have dropped lru lock
Date: Tue, 30 Jan 2024 00:09:04 +0000 [thread overview]
Message-ID: <Zbg-INqi9oMUqJaW@google.com> (raw)
In-Reply-To: <20240126-zswap-writeback-race-v2-1-b10479847099@bytedance.com>
On Sun, Jan 28, 2024 at 01:28:49PM +0000, Chengming Zhou wrote:
> LRU_SKIP can only be returned if we don't ever dropped lru lock, or
> we need to return LRU_RETRY to restart from the head of lru list.
>
> Otherwise, the iteration might continue from a cursor position that
> was freed while the locks were dropped.
Does this warrant a stable backport?
>
> Actually we may need to introduce another LRU_STOP to really terminate
> the ongoing shrinking scan process, when we encounter a warm page
> already in the swap cache. The current list_lru implementation
> doesn't have this function to early break from __list_lru_walk_one.
>
> Fixes: b5ba474f3f51 ("zswap: shrink zswap pool based on memory pressure")
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> Reviewed-by: Nhat Pham <nphamcs@gmail.com>
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
next prev parent reply other threads:[~2024-01-30 0:09 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-28 13:28 [PATCH v2 0/3] mm/zswap: fix race between lru writeback and swapoff Chengming Zhou
2024-01-28 13:28 ` [PATCH v2 1/3] mm/zswap: don't return LRU_SKIP if we have dropped lru lock Chengming Zhou
2024-01-30 0:09 ` Yosry Ahmed [this message]
2024-01-30 0:12 ` Nhat Pham
2024-01-30 0:58 ` Yosry Ahmed
2024-01-28 13:28 ` [PATCH v2 2/3] mm/zswap: fix race between lru writeback and swapoff Chengming Zhou
2024-01-30 0:22 ` Yosry Ahmed
2024-01-30 2:30 ` Chengming Zhou
2024-01-30 3:17 ` Johannes Weiner
2024-01-30 3:31 ` Chengming Zhou
2024-01-28 13:28 ` [PATCH v2 3/3] mm/list_lru: remove list_lru_putback() Chengming Zhou
2024-01-28 15:52 ` Johannes Weiner
2024-01-28 19:45 ` Nhat Pham
2024-01-30 0:34 ` Yosry Ahmed
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