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([2601:647:4802:9070:541c:8b1b:5ac:35fe]) by smtp.gmail.com with ESMTPSA id s23sm2000848pjs.47.2020.07.28.00.48.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 28 Jul 2020 00:48:40 -0700 (PDT) Subject: Re: [PATCH v5 1/2] blk-mq: add tagset quiesce interface To: Christoph Hellwig References: <20200727231022.307602-1-sagi@grimberg.me> <20200727231022.307602-2-sagi@grimberg.me> <20200728071859.GA21629@lst.de> From: Sagi Grimberg Message-ID: <54c7f095-c112-eaa7-3c69-65b4b48f2688@grimberg.me> Date: Tue, 28 Jul 2020 00:48:39 -0700 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: <20200728071859.GA21629@lst.de> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200728_034842_126408_F11BEBFB X-CRM114-Status: GOOD ( 19.25 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , "Paul E. McKenney" , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Chao Leng , Keith Busch , Ming Lin Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org > I like the tagset based interface. Even that we need to unquiesce back the connect_q? See my comment on v5. Kinda bothers me... But the idea of doing a per-hctx > allocation and wait doesn't seem very scalable. I belong to this camp too.. > Paul, do you have any good idea for an interface that waits on > multiple srcu heads? As far as I can tell we could just have a single > global completion and counter, and each call_srcu would just just > decrement it and then the final one would do the wakeup. It would just > be great to figure out a way to keep the struct rcu_synchronize and > counter on stack to avoid an allocation. > > But if we can't do with an on-stack object I'd much rather just embedd > the rcu_head in the hw_ctx. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme