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[84.110.32.226]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4214186ccdcsm34884405e9.16.2024.06.04.01.24.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Jun 2024 01:24:50 -0700 (PDT) Message-ID: <62c2b8cd-ce6a-4e13-a58c-a6b30a0dcf17@grimberg.me> Date: Tue, 4 Jun 2024 11:24:48 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/4] net: introduce helper sendpages_ok() To: Christoph Hellwig Cc: Ofir Gal , davem@davemloft.net, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, netdev@vger.kernel.org, ceph-devel@vger.kernel.org, dhowells@redhat.com, edumazet@google.com, pabeni@redhat.com, kbusch@kernel.org, axboe@kernel.dk, philipp.reisner@linbit.com, lars.ellenberg@linbit.com, christoph.boehmwalder@linbit.com, idryomov@gmail.com, xiubli@redhat.com References: <20240530142417.146696-1-ofir.gal@volumez.com> <20240530142417.146696-2-ofir.gal@volumez.com> <8d0c198f-9c15-4a8f-957a-2e4aecddd2e5@grimberg.me> <23821101-adf0-4e38-a894-fb05a19cb9c3@volumez.com> <86e60615-9286-4c9c-bffc-72304bd3cc1f@grimberg.me> <20240604042738.GA28853@lst.de> Content-Language: en-US From: Sagi Grimberg In-Reply-To: <20240604042738.GA28853@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240604_012455_178555_C39D830F X-CRM114-Status: GOOD ( 15.13 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 04/06/2024 7:27, Christoph Hellwig wrote: > On Tue, Jun 04, 2024 at 12:27:06AM +0300, Sagi Grimberg wrote: >>>> I still don't understand how a page in the middle of a contiguous range ends >>>> up coming from the slab while others don't. >>> I haven't investigate the origin of the IO >>> yet. I suspect the first 2 pages are the superblocks of the raid >>> (mdp_superblock_1 and bitmap_super_s) and the rest of the IO is the bitmap. >> Well, if these indeed are different origins and just *happen* to be a >> mixture >> of slab originated pages and non-slab pages combined together in a single >> bio of a bvec entry, >> I'd suspect that it would be more beneficial to split the bvec (essentially >> not allow bio_add_page >> to append the page to tail bvec depending on a queue limit (similar to how >> we handle sg gaps). > So you want to add a PageSlab check to bvec_try_merge_page? That sounds > fairly expensive.. > The check needs to happen somewhere apparently, and given that it will be gated by a queue flag only request queues that actually needed will suffer, but they will suffer anyways...