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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 F38B6C2D0CE for ; Tue, 21 Jan 2020 13:34:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD27D22314 for ; Tue, 21 Jan 2020 13:34:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727508AbgAUNel (ORCPT ); Tue, 21 Jan 2020 08:34:41 -0500 Received: from relay.sw.ru ([185.231.240.75]:34688 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726920AbgAUNel (ORCPT ); Tue, 21 Jan 2020 08:34:41 -0500 Received: from dhcp-172-16-24-104.sw.ru ([172.16.24.104]) by relay.sw.ru with esmtp (Exim 4.92.3) (envelope-from ) id 1ittfD-0007u7-5X; Tue, 21 Jan 2020 16:33:51 +0300 Subject: Re: [PATCH v4 6/7] dm: Directly disable max_allocate_sectors for now From: Kirill Tkhai To: Mike Snitzer Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, martin.petersen@oracle.com, bob.liu@oracle.com, axboe@kernel.dk, agk@redhat.com, dm-devel@redhat.com, song@kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, Chaitanya.Kulkarni@wdc.com, darrick.wong@oracle.com, ming.lei@redhat.com, osandov@fb.com, jthumshirn@suse.de, minwoo.im.dev@gmail.com, damien.lemoal@wdc.com, andrea.parri@amarulasolutions.com, hare@suse.com, tj@kernel.org, ajay.joshi@wdc.com, sagi@grimberg.me, dsterba@suse.com, bvanassche@acm.org, dhowells@redhat.com, asml.silence@gmail.com References: <157960325642.108120.13626623438131044304.stgit@localhost.localdomain> <157960337238.108120.18048939587162465175.stgit@localhost.localdomain> <20200121122458.GA9365@redhat.com> Message-ID: <619a7a14-44e6-eca7-c1ea-3f04abeee53d@virtuozzo.com> Date: Tue, 21 Jan 2020 16:33:50 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 21.01.2020 15:36, Kirill Tkhai wrote: > On 21.01.2020 15:24, Mike Snitzer wrote: >> On Tue, Jan 21 2020 at 5:42am -0500, >> Kirill Tkhai wrote: >> >>> Since dm inherits limits from underlining block devices, >>> this patch directly disables max_allocate_sectors for dm >>> till full allocation support is implemented. >>> >>> This prevents high-level primitives (generic_make_request_checks(), >>> __blkdev_issue_write_zeroes(), ...) from sending REQ_ALLOCATE >>> requests. >>> >>> Signed-off-by: Kirill Tkhai >>> --- >>> drivers/md/dm-table.c | 2 ++ >>> drivers/md/md.h | 1 + >>> 2 files changed, 3 insertions(+) >> >> You're mixing DM and MD changes in the same patch. >> >> But I'm wondering if it might be best to set this default for stacking >> devices in blk_set_stacking_limits()? >> >> And then it is up to each stacking driver to override as needed. > > Hm. Sound like a good idea. This "lim->max_allocate_sectors = 0" in blk_set_stacking_limits() > should work for dm's dm_calculate_queue_limits(), since it calls blk_stack_limits(), which is: > > t->max_allocate_sectors = min(t->max_allocate_sectors, > b->max_allocate_sectors); > > Could you please tell is this fix is also enough for md? It looks like it's enough since queue defaults are set in md_alloc()->blk_set_stacking_limits(). In case of we set "max_allocate_sectors = 0", in further it can be changed only manually, but nobody does this.