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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 53A3FC07E9B for ; Tue, 20 Jul 2021 09:09:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CAD06120F for ; Tue, 20 Jul 2021 09:09:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235996AbhGTI2v (ORCPT ); Tue, 20 Jul 2021 04:28:51 -0400 Received: from vulcan.natalenko.name ([104.207.131.136]:55732 "EHLO vulcan.natalenko.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235636AbhGTIZE (ORCPT ); Tue, 20 Jul 2021 04:25:04 -0400 Received: from spock.localnet (unknown [151.237.229.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by vulcan.natalenko.name (Postfix) with ESMTPSA id 6D05AB41E7E; Tue, 20 Jul 2021 11:05:31 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=natalenko.name; s=dkim-20170712; t=1626771931; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zTkNNItkMBlaqFMYurWQMqTjRu8UVH4wWx+Z1y3Sv9o=; b=NsWnK6DIEsHFO/M0/bzgppZTDvUtPXdBU0oyQHXWoDFC+rtKa0p9TmNGrulekbWKkUGV22 wIwfi0LscB5GHq+4sJa8fi9yyKoY8CnOfMvQ/nq+BgNwkR8NtqjvetL8vTCFQzQG8Bx0LQ ZM8huj4wu4W8qKswXrpe1JIxbSqrvB4= From: Oleksandr Natalenko To: Ming Lei Cc: linux-kernel@vger.kernel.org, Jens Axboe , Christoph Hellwig , Sagi Grimberg , linux-nvme@lists.infradead.org, David Jeffery , Laurence Oberman , Paolo Valente , Jan Kara , Sasha Levin , Greg Kroah-Hartman , Keith Busch Subject: Re: New warning in nvme_setup_discard Date: Tue, 20 Jul 2021 11:05:29 +0200 Message-ID: <2356877.Yf5hrMSTGe@natalenko.name> In-Reply-To: <2407736.Le3fEKZpXq@natalenko.name> References: <4729812.CpyZKHjjVO@natalenko.name> <2407736.Le3fEKZpXq@natalenko.name> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Ming. On pond=C4=9Bl=C3=AD 19. =C4=8Dervence 2021 8:27:29 CEST Oleksandr Natalenk= o wrote: > On pond=C4=9Bl=C3=AD 19. =C4=8Dervence 2021 3:40:40 CEST Ming Lei wrote: > > On Sat, Jul 17, 2021 at 02:35:14PM +0200, Oleksandr Natalenko wrote: > > > On sobota 17. =C4=8Dervence 2021 14:19:59 CEST Oleksandr Natalenko wr= ote: > > > > On sobota 17. =C4=8Dervence 2021 14:11:05 CEST Oleksandr Natalenko = wrote: > > > > > On sobota 17. =C4=8Dervence 2021 11:35:32 CEST Ming Lei wrote: > > > > > > Maybe you need to check if the build is OK, I can't reproduce it > > > > > > in > > > > > > my > > > > > > VM, and BFQ is still builtin: > > > > > >=20 > > > > > > [root@ktest-01 ~]# uname -a > > > > > > Linux ktest-01 5.14.0-rc1+ #52 SMP Fri Jul 16 18:56:36 CST 2021 > > > > > > x86_64 > > > > > > x86_64 x86_64 GNU/Linux [root@ktest-01 ~]# cat > > > > > > /sys/block/nvme0n1/queue/scheduler > > > > > > [none] mq-deadline kyber bfq > > > > >=20 > > > > > I don't think this is an issue with the build=E2=80=A6 BTW, with > > > > > `initcall_debug`: > > > > >=20 > > > > > ``` > > > > > [ 0.902555] calling bfq_init+0x0/0x8b @ 1 > > > > > [ 0.903448] initcall bfq_init+0x0/0x8b returned -28 after 507 > > > > > usecs > > > > > ``` > > > > >=20 > > > > > -ENOSPC? Why? Also re-tested with the latest git tip, same result > > > > > :(. > > > >=20 > > > > OK, one extra pr_info, and I see this: > > > >=20 > > > > ``` > > > > [ 0.871180] blkcg_policy_register: BLKCG_MAX_POLS too small > > > > [ 0.871612] blkcg_policy_register: -28 > > > > ``` > > > >=20 > > > > What does it mean please :)? The value seems to be hard-coded: > > > >=20 > > > > ``` > > > > include/linux/blkdev.h > > > > 60:#define BLKCG_MAX_POLS 5 > > > > ``` > > >=20 > > > OK, after increasing this to 6 I've got my BFQ back. Please see [1]. > > >=20 > > > [1] > > > https://lore.kernel.org/linux-block/20210717123328.945810-1-oleksandr= @na > > > t > > > alenko.name/ > >=20 > > OK, after you fixed the issue in blkcg_policy_register(), can you > > reproduce the discard issue on v5.14-rc1 with BFQ applied? If yes, > > can you test the patch I posted previously? >=20 > Yes, the issue is reproducible with both v5.13.2 and v5.14-rc1. I haven't > managed to reproduce it with v5.13.2+your patch. Now I will build v5.14- > rc2+your patch and test further. I'm still hammering v5.14-rc2 + your patch, and I cannot reproduce the issu= e.=20 Given I do not have a reliable reproducer (I'm just firing up the kernel bu= ild,=20 and the issue pops up eventually, sooner or later, but usually within a cou= ple=20 of first tries), for how long I should hammer it for your fix to be conside= red=20 proven? Thanks. =2D-=20 Oleksandr Natalenko (post-factum)