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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 5808EC10F11 for ; Thu, 25 Apr 2019 00:41:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20707214C6 for ; Thu, 25 Apr 2019 00:41:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726533AbfDYAlV (ORCPT ); Wed, 24 Apr 2019 20:41:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43236 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726455AbfDYAlV (ORCPT ); Wed, 24 Apr 2019 20:41:21 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9EBB3356F1; Thu, 25 Apr 2019 00:41:20 +0000 (UTC) Received: from ming.t460p (ovpn-8-18.pek2.redhat.com [10.72.8.18]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C63E35D9C5; Thu, 25 Apr 2019 00:41:12 +0000 (UTC) Date: Thu, 25 Apr 2019 08:41:07 +0800 From: Ming Lei To: Sagi Grimberg Cc: Hannes Reinecke , Jens Axboe , Hannes Reinecke , Bart van Assche , Ming Lei , neilb@suse.com, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Christoph Hellwig , Kent Overstreet Subject: Re: [PATCH] block: use static bio_set for bio_split() calls Message-ID: <20190425004106.GA22683@ming.t460p> References: <20190418140632.60606-1-hare@suse.de> <20190418143429.GA19175@ming.t460p> <98d8549a-2663-b404-e38a-6f55dfb575bf@grimberg.me> <20190424221422.GA21351@ming.t460p> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190424221422.GA21351@ming.t460p> User-Agent: Mutt/1.9.1 (2017-09-22) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 25 Apr 2019 00:41:21 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Apr 25, 2019 at 06:14:22AM +0800, Ming Lei wrote: > On Wed, Apr 24, 2019 at 10:20:46AM -0700, Sagi Grimberg wrote: > > > > > per-queue bioset is used originally for avoiding deadlock, are you > > > sure the static bioset is safe? > > > > Can you explain this? I didn't find any indication of that in the change > > log history... > > > > Originally introduced by Kent: > > bio split can be run from stacking drivers, for example, MD over NVMe, > if the global reserved mempool is consumed by MD bio splitting, then > no any progress can be made when splitting on bio submitted to NVMe. > > Kent may have more details... I guess it might be fine to use one shared global bio_set for all lowest underlying queues, could be all queues except for loop, dm, md , drbd, bcache, ... Thanks, Ming From mboxrd@z Thu Jan 1 00:00:00 1970 From: ming.lei@redhat.com (Ming Lei) Date: Thu, 25 Apr 2019 08:41:07 +0800 Subject: [PATCH] block: use static bio_set for bio_split() calls In-Reply-To: <20190424221422.GA21351@ming.t460p> References: <20190418140632.60606-1-hare@suse.de> <20190418143429.GA19175@ming.t460p> <98d8549a-2663-b404-e38a-6f55dfb575bf@grimberg.me> <20190424221422.GA21351@ming.t460p> Message-ID: <20190425004106.GA22683@ming.t460p> On Thu, Apr 25, 2019@06:14:22AM +0800, Ming Lei wrote: > On Wed, Apr 24, 2019@10:20:46AM -0700, Sagi Grimberg wrote: > > > > > per-queue bioset is used originally for avoiding deadlock, are you > > > sure the static bioset is safe? > > > > Can you explain this? I didn't find any indication of that in the change > > log history... > > > > Originally introduced by Kent: > > bio split can be run from stacking drivers, for example, MD over NVMe, > if the global reserved mempool is consumed by MD bio splitting, then > no any progress can be made when splitting on bio submitted to NVMe. > > Kent may have more details... I guess it might be fine to use one shared global bio_set for all lowest underlying queues, could be all queues except for loop, dm, md , drbd, bcache, ... Thanks, Ming