Message-ID: <b3a200b7-e9c5-4627-409c-e198ac1dc30a@suse.cz>
Date:   Thu, 9 Mar 2023 10:23:57 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.8.0
Subject: Re: [PATCH v4 4/8] mm: vmscan: add shrinker_srcu_generation
Content-Language: en-US
To:     Qi Zheng <zhengqi.arch@bytedance.com>, akpm@linux-foundation.org,
        tkhai@ya.ru, hannes@cmpxchg.org, shakeelb@google.com,
        mhocko@kernel.org, roman.gushchin@linux.dev, muchun.song@linux.dev,
        david@redhat.com, shy828301@gmail.com, rppt@kernel.org
Cc:     sultan@kerneltoast.com, dave@stgolabs.net,
        penguin-kernel@I-love.SAKURA.ne.jp, paulmck@kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20230307065605.58209-1-zhengqi.arch@bytedance.com>
 <20230307065605.58209-5-zhengqi.arch@bytedance.com>
From:   Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <20230307065605.58209-5-zhengqi.arch@bytedance.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 3/7/23 07:56, Qi Zheng wrote:
> From: Kirill Tkhai <tkhai@ya.ru>
> 
> After we make slab shrink lockless with SRCU, the longest
> sleep unregister_shrinker() will be a sleep waiting for
> all do_shrink_slab() calls.
> 
> To aviod long unbreakable action in the unregister_shrinker(),

     ^ avoid

> add shrinker_srcu_generation to restore a check similar to the
> rwsem_is_contendent() check that we had before.
> 
> And for memcg slab shrink, we unlock SRCU and continue
> iterations from the next shrinker id.
> 
> Signed-off-by: Kirill Tkhai <tkhai@ya.ru>
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>