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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 CFEFBC433E6 for ; Sat, 20 Feb 2021 19:20:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9DCDC64EDE for ; Sat, 20 Feb 2021 19:20:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229918AbhBTTUP (ORCPT ); Sat, 20 Feb 2021 14:20:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:48552 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229808AbhBTTUI (ORCPT ); Sat, 20 Feb 2021 14:20:08 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5BF2264E51; Sat, 20 Feb 2021 19:19:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1613848768; bh=opkZV9+iiOg5i7CeRhciYmBMWsz/qz9Xmo/qIEL+++w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lAzR3vLqQJN7zA0sj+1l2vnXCMVW4WzYcT/7zoi2XEkR75dxEfZxsr9ZZXs0vfoPA MIIgjdK8Bfi/OCFnVUkAXbnH1QuOe78GE9Zog3tA5xLd9ntizTOGRftkJ5DbbTpQLW omYiai3857LXH2o97xCBrMSxBqmNpxN940EtlMYI230TK91985WJW6trAwt3FkdY/L VqIe5cfn3Bm95NdASEstDvnzMUXt7VhCJVGdKAJfJ58WvX9DqAgAts08MiZ6GAolne 0nuR0yF2z+6rnQQ4z7QrJaZEUfQQrwShmPsQQ1TDKXSeEoktfn9AzBO1+I/LSxew2+ 2ipaElzzXH/Mw== Date: Sun, 21 Feb 2021 04:19:21 +0900 From: Keith Busch To: David Laight Cc: 'SelvaKumar S' , "linux-nvme@lists.infradead.org" , "axboe@kernel.dk" , "damien.lemoal@wdc.com" , "hch@lst.de" , "sagi@grimberg.me" , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "dm-devel@redhat.com" , "snitzer@redhat.com" , "selvajove@gmail.com" , "joshiiitr@gmail.com" , "nj.shetty@samsung.com" , "joshi.k@samsung.com" , "javier.gonz@samsung.com" , "kch@kernel.org" , "linux-fsdevel@vger.kernel.org" Subject: Re: [RFC PATCH v5 0/4] add simple copy support Message-ID: <20210220191921.GA7968@redsun51.ssa.fujisawa.hgst.com> References: <20210219124517.79359-1-selvakuma.s1@samsung.com> <146c47907c2446d4a896830de400dd81@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <146c47907c2446d4a896830de400dd81@AcuMS.aculab.com> User-Agent: Mutt/1.12.1 (2019-06-15) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 20, 2021 at 06:01:56PM +0000, David Laight wrote: > From: SelvaKumar S > > Sent: 19 February 2021 12:45 > > > > This patchset tries to add support for TP4065a ("Simple Copy Command"), > > v2020.05.04 ("Ratified") > > > > The Specification can be found in following link. > > https://nvmexpress.org/wp-content/uploads/NVM-Express-1.4-Ratified-TPs-1.zip > > > > Simple copy command is a copy offloading operation and is used to copy > > multiple contiguous ranges (source_ranges) of LBA's to a single destination > > LBA within the device reducing traffic between host and device. > > Sounds to me like the real reason is that the copy just ends up changing > some indirect block pointers rather than having to actually copy the data. I guess an implementation could do that, but I think that's missing the point of the command. The intention is to copy the data to a new location on the media for host managed garbage collection.