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=-4.3 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 7656BC433E0 for ; Tue, 9 Feb 2021 00:53:35 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 1292061606 for ; Tue, 9 Feb 2021 00:53:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1292061606 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kioxia.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:Message-ID:Date:Subject:To: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:List-Owner; bh=vk9m2umcD9HtFkQAYKxFT351QaCMqEShMY4zjBFwnZY=; b=q7pL9SLJ75F6HNN8BDUvoN+/X LzXlc/Kni+MaeJs1Gw4XkFXCFY828JLPxgiveWXqwXpdDjeCBkdd0SZa/1yJePzhi1XqRGAkkTbxO Z1zOugXaQgCNuVPtYl+J5Cv0VAlj9yepXd5WN8O3LMT+T+ijVYaT6SxrUleWPOPJ91kByUdFqmQ3i 9xvqRaDr9unCBybkKBOgrTLyD033lDaL+3g0zS7vb7IElTwLrxwuZt6vERq5sUmLXG33LreFh+5Km t86Ct6dyN7DdEh1ZUbMoGTr+MksqHClQCQu+9GZllv752ujqG8iShPlECrpVZIIWYxkUq48gP5S+5 cIjaq8VGA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l9HHU-0002C9-1C; Tue, 09 Feb 2021 00:53:28 +0000 Received: from usmailhost21.kioxia.com ([12.0.68.226] helo=SJSMAIL01.us.kioxia.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l9HHO-0002Av-UW for linux-nvme@lists.infradead.org; Tue, 09 Feb 2021 00:53:26 +0000 Received: from SJSMAIL01.us.kioxia.com (10.90.133.90) by SJSMAIL01.us.kioxia.com (10.90.133.90) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Mon, 8 Feb 2021 16:53:17 -0800 Received: from SJSMAIL01.us.kioxia.com ([fe80::98fb:6d15:be65:b22d]) by SJSMAIL01.us.kioxia.com ([fe80::98fb:6d15:be65:b22d%3]) with mapi id 15.01.1779.007; Mon, 8 Feb 2021 16:53:17 -0800 From: Clay Mayers To: "linux-nvme@lists.infradead.org" Subject: RE: [PATCH V2 0/2] nvme: Support for fused NVME_IOCTL_SUBMIT_IO Thread-Topic: [PATCH V2 0/2] nvme: Support for fused NVME_IOCTL_SUBMIT_IO Thread-Index: AQHW81Uk6e6cbZGyEU2+tznAk87Vf6o6RTXQgBS+TpA= Date: Tue, 9 Feb 2021 00:53:17 +0000 Message-ID: References: <20210105224939.1336-2-clay.mayers@kioxia.com> <20210125195844.1390581-1-clay.mayers@kioxia.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.90.53.138] MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210208_195323_028012_31E2543C X-CRM114-Status: GOOD ( 11.18 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Keith Busch , Jens Axboe , Christoph Hellwig , Chaitanya Kulkarni , Sagi Grimberg 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 > From: Clay Mayers > Sent: Tuesday, January 26, 2021 1:14 PM > To: linux-nvme@lists.infradead.org > Cc: Keith Busch ; Jens Axboe ; > 'Chaitanya Kulkarni' ; > Christoph Hellwig ; Sagi Grimberg > Subject: RE: [PATCH V2 0/2] nvme: Support for fused > NVME_IOCTL_SUBMIT_IO > Is there any other feedback on V2? My main concern I have about my implementation is how fused requests are tunneled through the mq request layer. The 1st request is marked as started but it won't be in the device until the 2nd command is queued. As Keith pointed out, a device reset can split the two so care must be taken to correctly handle this case. Despite this, I thought this was a better approach than modifying mq requests to be fused. Especially given Christoph's concern of cost vs value. This is the lightest touch I could come up with. Further consideration of this patch may need a more compelling use case. I've worked on a proprietary storage systems that relied on fused NVMeOF support so it seems compelling to me. There's a comment in target/core.c that there is "no support for fused commands yet" implying it's been considered. Is pci only support for fused too soon or too little? What would make it more compelling? _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme