From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6CDEFC25B74 for ; Tue, 4 Jun 2024 04:27:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=OUjQnxYzptd3jr3rpOALpRW9VtJfeXZt7RzDyIvJawU=; b=rWhKj3xsO8HW4J/c+LQPYoR/fB coKMcWRjw6EllKaa/K72sbe+fhpiFhLFdt8qo7C0uMJq3eM59ZoNxNk1Gno48AIFYV/htI2J1P8Ih TRfzGbWVNOzLf7h7xjiCvpVLjguRERowQKebil+bz16UZspRnGumpYqBwRGfhbyk6PDiG+f/q+X/V ZmyxNOp1x9Gb3BMIp57A6McvB4n+8ci39RmCRdrSxX5vjUQfa5XJ/crGBEvsuyJ9g5K2dC2kuj03d kNB21XyUkuQ/RZI1GDvK5YqLWPTzKWYm9t06c4Dm34zAC5V/dM3yqTeurHmBuWSR0PkR/8Ss8rjEO nLZKi3Rw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sELlx-00000001B1J-2tUe; Tue, 04 Jun 2024 04:27:45 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sELlu-00000001B0V-3nqr for linux-nvme@lists.infradead.org; Tue, 04 Jun 2024 04:27:44 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id A2E5F68D15; Tue, 4 Jun 2024 06:27:38 +0200 (CEST) Date: Tue, 4 Jun 2024 06:27:38 +0200 From: Christoph Hellwig To: Sagi Grimberg 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, hch@lst.de, philipp.reisner@linbit.com, lars.ellenberg@linbit.com, christoph.boehmwalder@linbit.com, idryomov@gmail.com, xiubli@redhat.com Subject: Re: [PATCH v2 1/4] net: introduce helper sendpages_ok() Message-ID: <20240604042738.GA28853@lst.de> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <86e60615-9286-4c9c-bffc-72304bd3cc1f@grimberg.me> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240603_212743_114518_75F175B1 X-CRM114-Status: GOOD ( 17.97 ) 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 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..