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Fri, 11 Sep 2020 11:45:50 -0700 (PDT) Subject: Re: [PATCH V5 0/4] blk-mq: implement queue quiesce via percpu_ref for BLK_MQ_F_BLOCKING To: Sagi Grimberg , Ming Lei , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Christoph Hellwig , Keith Busch Cc: Hannes Reinecke , Bart Van Assche , Johannes Thumshirn , Chao Leng References: <20200911024117.62480-1-ming.lei@redhat.com> <4fb604fd-c081-5eb1-cb3a-860746b6952a@grimberg.me> <09d5cb96-b442-6965-96b3-d884c95a3ca7@grimberg.me> From: Jens Axboe Message-ID: Date: Fri, 11 Sep 2020 12:45:49 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <09d5cb96-b442-6965-96b3-d884c95a3ca7@grimberg.me> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 9/11/20 12:34 PM, Sagi Grimberg wrote: > >>> Hi Jens, >>> >>> The 1st patch add .mq_quiesce_mutex for serializing quiesce/unquiesce, >>> and prepares for replacing srcu with percpu_ref. >>> >>> The 2nd patch replaces srcu with percpu_ref. >>> >>> The 3rd patch adds tagset quiesce interface. >>> >>> The 4th patch applies tagset quiesce interface for NVMe subsystem. >> >> Tested some reset storms and target restarts during traffic with >> nvme-tcp. >> >> Seems that no apparent breakage. >> >> So: >> >> Tested-by: Sagi Grimberg > > Probably unrelated to this patches, but I do see new > kmemleak complaints in the form of: > -- > unreferenced object 0xffff9440dbf3c240 (size 64): > comm "systemd", pid 1, jiffies 4306444056 (age 25034.440s) > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 b0 fe 13 99 ff ff ff ff ................ > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > backtrace: > [<00000000f1d0b20e>] percpu_ref_init+0x5f/0xf0 > [<000000009598103f>] cgroup_mkdir+0xe9/0x440 > [<0000000001b93c19>] kernfs_iop_mkdir+0x57/0x80 > [<000000001ed0f985>] vfs_mkdir+0x10e/0x1d0 > [<00000000cac65f7e>] do_mkdirat+0xec/0x120 > [<00000000956db630>] do_syscall_64+0x33/0x80 > [<000000001c2b0e1a>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Looks more related to the percpu_ref changes that allocate it dynamically, causing issues on cases that forget to exit the ref. -- Jens Axboe