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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE0CEC4338F for ; Thu, 22 Jul 2021 21:00:53 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id A2BD960EB5 for ; Thu, 22 Jul 2021 21:00:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A2BD960EB5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=1uMroxtqg4Oyw1fmh6rR4jDhm8D2aBLm0A8DSa3Syq0=; b=TsAHbxA4StPEck atWiFGs38wS8W7mcH0sgLeOmsP4zTAFkxZ9edT5kSXx8J9bSOmnNEKrSwsvbz/JbpGCisY/feZPG3 ls2h/ECivfj7yTaEWALKVMD3xYIBwxBy/QtmUUEL1Zg+PrXjFk3Zg728I1bQKIKG6kAMofFkA0GUk 7JnbhV03ffUparXp/gmRI7rIPxEmAtvAjvFR+RAp+IJo7g03tikKBSukH53NFi9yBWJcHR8HCoBP7 jr4BeOR+gg6MSHu3w2D+Mopc3ZN1j+Gy6zGSx0GaefuJnswQi7yQZrmjGYcZC9FshnupdmcDBBVA3 uc+5+zQpZ3ua0lM/Gu6g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6foG-002lMT-M1; Thu, 22 Jul 2021 21:00:48 +0000 Received: from zeniv-ca.linux.org.uk ([142.44.231.140]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6fo8-002lKY-AX for linux-nvme@lists.infradead.org; Thu, 22 Jul 2021 21:00:41 +0000 Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6fj8-002yyA-IB; Thu, 22 Jul 2021 20:55:30 +0000 Date: Thu, 22 Jul 2021 20:55:30 +0000 From: Al Viro To: Boris Pismenny Cc: dsahern@gmail.com, kuba@kernel.org, davem@davemloft.net, saeedm@nvidia.com, hch@lst.de, sagi@grimberg.me, axboe@fb.com, kbusch@kernel.org, edumazet@google.com, smalin@marvell.com, boris.pismenny@gmail.com, linux-nvme@lists.infradead.org, netdev@vger.kernel.org, benishay@nvidia.com, ogerlitz@nvidia.com, yorayz@nvidia.com, Boris Pismenny , Ben Ben-Ishay , Or Gerlitz , Yoray Zack Subject: Re: [PATCH v5 net-next 02/36] iov_iter: DDP copy to iter/pages Message-ID: References: <20210722110325.371-1-borisp@nvidia.com> <20210722110325.371-3-borisp@nvidia.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210722110325.371-3-borisp@nvidia.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210722_140040_408019_48A5F94E X-CRM114-Status: GOOD ( 12.11 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Jul 22, 2021 at 02:02:51PM +0300, Boris Pismenny wrote: > From: Boris Pismenny > > When using direct data placement (DDP) the NIC writes some of the payload > directly to the destination buffer, and constructs SKBs such that they > point to this data. To skip copies when SKB data already resides in the > destination we use the newly introduced routines in this commit, which > check if (src == dst), and skip the copy when that's true. > > As the current user for these routines is in the block layer (nvme-tcp), > then we only apply the change for bio_vec. Other routines use the normal > methods for copying. Please, take a look at -rc1 and see the changes in lib/iov_iter.c in there. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme