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Tue, 13 Dec 2022 11:31:01 -0800 (PST) Received: from localhost ([2620:10d:c090:400::5:c415]) by smtp.gmail.com with ESMTPSA id i63-20020a62c142000000b00572198393c2sm7986815pfg.194.2022.12.13.11.31.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Dec 2022 11:31:00 -0800 (PST) Date: Tue, 13 Dec 2022 09:30:59 -1000 From: Tejun Heo To: Waiman Long Cc: Jens Axboe , Josef Bacik , Zefan Li , Johannes Weiner , Andrew Morton , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal =?iso-8859-1?Q?Koutn=FD?= , "Dennis Zhou (Facebook)" Subject: Re: [PATCH-block v3 2/2] blk-cgroup: Flush stats at blkgs destruction path Message-ID: References: <20221213184446.50181-1-longman@redhat.com> <20221213184446.50181-3-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221213184446.50181-3-longman@redhat.com> X-Rspam-User: X-Rspamd-Queue-Id: 6181F140002 X-Rspamd-Server: rspam01 X-Stat-Signature: dd7dftmtz3qz6zbpnx9tt14dy6y4m5kn X-HE-Tag: 1670959862-951730 X-HE-Meta: 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 BgIofQLP 2ATUJVercOqw1+wQfIh3U8JJCBKeEVaS+VqS5tzCtjdbZZwK5T6ZHDCz30fxoSG0t6mtJcJSsuQx6IsZfcSqWqtyBb5Wvd906GSoR6tZJHL3AQb9IZct7zE2oFAcGE56A8hWHLjas5LTVOI05Bhr1GrUj0+H9zzplvMcxAM0+FYqjYFqkl0i7eJydgPPN1f9umsfGoAaJt/REzJh9CgIBLfMcs6JKeP7f0lDOz97g3+g8OPWBQ0wZxLLIHg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Dec 13, 2022 at 01:44:46PM -0500, Waiman Long wrote: > + /* > + * Flush all the non-empty percpu lockless lists so as to release > + * the blkg references held by those lists which, in turn, may > + * allow the blkgs to be freed and release their references to > + * blkcg speeding up its freeing. > + */ Can you mention the possible deadlock explicitly? This sounds more like an optimization. Thanks. -- tejun