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 C1D4DC4345F for ; Mon, 29 Apr 2024 17:07:42 +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=tK0K6yuM2ErZaa56FWFc/pUIfXVI8UrCztL55MVgwKA=; b=MC9APlhNEiFUqjn+1dKQvR3I+5 RCQ7RNA6imHY2tLtWnvT2lk4ElJ48q9NhcWY5OwQlGOIpaBG09TYDqMVDmE+d83uVQ69OUXe7SwM/ bMLpC3u75W93mc8BqKiMo3IK5JBodmCQ4Ps4MidL/deWBhZbCidklV+nrnWfBd6eMbTkk278FlJ/1 N7omID/3c2ReRN74z/R25SImiAs4HcKBRSg42RVKVtq9blpV5DWzcI2Y8c10QQR9sHEbn9WwAZmy2 TdUUEPszahyB2txTsV0RwHXnEvQb1/t4oi5qym6CThQKWlBvL7ZRhxaw8Jf7yaTtFnaU5HYDpn9Z5 w9Bwekrw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1s1UTb-00000003gAf-3HFO; Mon, 29 Apr 2024 17:07:39 +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 1s1UTX-00000003g55-4BKq for linux-nvme@lists.infradead.org; Mon, 29 Apr 2024 17:07:37 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 5B467227A87; Mon, 29 Apr 2024 19:07:29 +0200 (CEST) Date: Mon, 29 Apr 2024 19:07:29 +0200 From: Christoph Hellwig To: Keith Busch Cc: Kanchan Joshi , Christoph Hellwig , axboe@kernel.dk, martin.petersen@oracle.com, brauner@kernel.org, asml.silence@gmail.com, dw@davidwei.uk, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, gost.dev@samsung.com, Anuj Gupta Subject: Re: [PATCH 02/10] block: copy bip_max_vcnt vecs instead of bip_vcnt during clone Message-ID: <20240429170728.GA31337@lst.de> References: <20240425183943.6319-1-joshi.k@samsung.com> <20240425183943.6319-3-joshi.k@samsung.com> <20240427070331.GB3873@lst.de> <73cc82c3-fbf6-ea3e-94ec-3bdce55af541@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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-20240429_100736_201926_D31D7DDF X-CRM114-Status: GOOD ( 15.43 ) 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 Mon, Apr 29, 2024 at 01:04:12PM +0100, Keith Busch wrote: > An earlier version added a field in the bip to point to the original > bvec from the user address. That extra field wouldn't be used in the far > majority of cases, so moving the user bvec to the end of the existing > bip_vec is a spatial optimization. The code may look a little more > confusing that way, but I think it's better than making the bip bigger. I think we need to do something like that - just hiding the bounce buffer is not really maintainable once we get multiple levels of stacking and other creative bio cloning.