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Date: Tue, 5 Mar 2024 10:09:23 -0500
From: Johannes Weiner <hannes@cmpxchg.org>
To: Chengming Zhou <chengming.zhou@linux.dev>
Cc: akpm@linux-foundation.org, yosryahmed@google.com, nphamcs@gmail.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	kernel test robot <oliver.sang@intel.com>
Subject: Re: [PATCH mm-unstable] mm/zswap: global lru and shrinker shared by
 all zswap_pools fix
Message-ID: <20240305150923.GB1491027@cmpxchg.org>
References: <20240210-zswap-global-lru-v3-1-200495333595@bytedance.com>
 <20240305075345.1493214-1-chengming.zhou@linux.dev>
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In-Reply-To: <20240305075345.1493214-1-chengming.zhou@linux.dev>

On Tue, Mar 05, 2024 at 07:53:45AM +0000, Chengming Zhou wrote:
> The commit bf9b7df23cb3 ("mm/zswap: global lru and shrinker shared by
> all zswap_pools") introduced a new lock to protect zswap_next_shrink,
> instead of reusing zswap_pools_lock.
> 
> But the problem is that it's initialized only when zswap enabled,
> which causes bug if zswap_memcg_offline_cleanup() called without
> zswap enabled.
> 
> Fix it by using DEFINE_SPINLOCK() to statically initialize them
> and define them as multiple static variables to keep in consistent
> with the existing global variables in zswap.
> 
> Fixes: bf9b7df23cb3 ("mm/zswap: global lru and shrinker shared by all zswap_pools")
> Reported-by: kernel test robot <oliver.sang@intel.com>
> Closes: https://lore.kernel.org/oe-lkp/202403051008.a8cf8a94-lkp@intel.com
> Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>