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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 065C3C433EF for ; Tue, 21 Dec 2021 16:21:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239591AbhLUQVs (ORCPT ); Tue, 21 Dec 2021 11:21:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236213AbhLUQVr (ORCPT ); Tue, 21 Dec 2021 11:21:47 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4AC50C061574 for ; Tue, 21 Dec 2021 08:21:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=QMre7yUdiStof2atRavqSpTRCc6/AnhtGt+tSsPd3MY=; b=e6utLqY6kTAViu0kjZBWn9FCY8 CO3PbjwYjfVjEqZzalVtljhrMW7lUfROG5LF7f0fhLqLbx5m14XQVmYDW2s+KSNi1+bfKxJ8fvhS5 pzKdTDajTaahR55SZbdVO58PIH3rbm1Cy6kIViPaVpZXLjofQWmW+E1bJILNkGl6tbQhwCzRND5KM UbYNdq/3lDqvEfjHIyLETIPUHOe/m7f3hvdIDSBwMub0K45Ux3t9zliwM9F3nZ47HGQJUew1rqzAL 5TeoQUa9N25SuKeAYfvV/lJxhCvXsr9GgEk5yS0J16nPXxvATyWba8IO8YQ7U1IMl8B1Lc8eYIay2 e1amTxMA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mzhtT-007Xsf-Lh; Tue, 21 Dec 2021 16:21:39 +0000 Date: Tue, 21 Dec 2021 08:21:39 -0800 From: Christoph Hellwig To: Ming Lei Cc: Jens Axboe , Mike Snitzer , linux-block@vger.kernel.org, dm-devel@redhat.com Subject: Re: [PATCH 0/3] blk-mq/dm-rq: support BLK_MQ_F_BLOCKING for dm-rq Message-ID: References: <20211221141459.1368176-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211221141459.1368176-1-ming.lei@redhat.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Dec 21, 2021 at 10:14:56PM +0800, Ming Lei wrote: > Hello, > > dm-rq may be built on blk-mq device which marks BLK_MQ_F_BLOCKING, so > dm_mq_queue_rq() may become to sleep current context. > > Fixes the issue by allowing dm-rq to set BLK_MQ_F_BLOCKING in case that > any underlying queue is marked as BLK_MQ_F_BLOCKING. > > DM request queue is allocated before allocating tagset, this way is a > bit special, so we need to pre-allocate srcu payload, then use the queue > flag of QUEUE_FLAG_BLOCKING for locking dispatch. What is the benefit over just forcing bio-based dm-mpath for these devices? 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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 9B9CBC433F5 for ; Tue, 21 Dec 2021 17:42:10 +0000 (UTC) Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-460-TbIuhHJUOCWsnq1fxawJlA-1; Tue, 21 Dec 2021 12:42:01 -0500 X-MC-Unique: TbIuhHJUOCWsnq1fxawJlA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 265238015C6; Tue, 21 Dec 2021 17:41:57 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7064345D99; Tue, 21 Dec 2021 17:41:55 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 9058D1802E2C; Tue, 21 Dec 2021 17:41:52 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 1BLGxWJp022510 for ; Tue, 21 Dec 2021 11:59:33 -0500 Received: by smtp.corp.redhat.com (Postfix) id 77AD92026612; Tue, 21 Dec 2021 16:59:32 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast04.extmail.prod.ext.rdu2.redhat.com [10.11.55.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 713EF202660C for ; Tue, 21 Dec 2021 16:59:29 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6DD10101A52D for ; Tue, 21 Dec 2021 16:59:29 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-17-4YsZustEPCeuwp4sdV62eg-1; Tue, 21 Dec 2021 11:59:28 -0500 X-MC-Unique: 4YsZustEPCeuwp4sdV62eg-1 Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mzhtT-007Xsf-Lh; Tue, 21 Dec 2021 16:21:39 +0000 Date: Tue, 21 Dec 2021 08:21:39 -0800 From: Christoph Hellwig To: Ming Lei Message-ID: References: <20211221141459.1368176-1-ming.lei@redhat.com> MIME-Version: 1.0 In-Reply-To: <20211221141459.1368176-1-ming.lei@redhat.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-loop: dm-devel@redhat.com Cc: Jens Axboe , linux-block@vger.kernel.org, dm-devel@redhat.com, Mike Snitzer Subject: Re: [dm-devel] [PATCH 0/3] blk-mq/dm-rq: support BLK_MQ_F_BLOCKING for dm-rq X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Tue, Dec 21, 2021 at 10:14:56PM +0800, Ming Lei wrote: > Hello, > > dm-rq may be built on blk-mq device which marks BLK_MQ_F_BLOCKING, so > dm_mq_queue_rq() may become to sleep current context. > > Fixes the issue by allowing dm-rq to set BLK_MQ_F_BLOCKING in case that > any underlying queue is marked as BLK_MQ_F_BLOCKING. > > DM request queue is allocated before allocating tagset, this way is a > bit special, so we need to pre-allocate srcu payload, then use the queue > flag of QUEUE_FLAG_BLOCKING for locking dispatch. What is the benefit over just forcing bio-based dm-mpath for these devices? -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel