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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 4A927C46469 for ; Wed, 12 Sep 2018 08:58:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0E212087F for ; Wed, 12 Sep 2018 08:58:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0E212087F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727781AbeILOCV (ORCPT ); Wed, 12 Sep 2018 10:02:21 -0400 Received: from mx2.suse.de ([195.135.220.15]:47504 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726624AbeILOCV (ORCPT ); Wed, 12 Sep 2018 10:02:21 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 3910AB016; Wed, 12 Sep 2018 08:58:46 +0000 (UTC) Date: Wed, 12 Sep 2018 10:58:45 +0200 Message-ID: From: Takashi Iwai To: Jens Axboe Cc: Jeff Moyer , Paolo Valente , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [REGRESSION] bfq probe failed on 4.19-rc3 In-Reply-To: <8d5f3ab2-50e8-226c-8ccb-c722872910db@kernel.dk> References: <8b5a7dc9-2dc1-16ee-4b05-a72eb6680c77@kernel.dk> <8d5f3ab2-50e8-226c-8ccb-c722872910db@kernel.dk> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/26 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 11 Sep 2018 18:54:19 +0200, Jens Axboe wrote: > > On 9/11/18 10:51 AM, Jeff Moyer wrote: > > Jens Axboe writes: > > > >> On 9/11/18 10:48 AM, Jeff Moyer wrote: > >>> Jens Axboe writes: > >>> > >>>> On 9/11/18 10:03 AM, Takashi Iwai wrote: > >>>>> Hi, > >>>>> > >>>>> I noticed that bfq doesn't appear in the I/O scheduler list on > >>>>> 4.19-rc3. It seems that blkcg_policy_register() at the beginning of > >>>>> bfq_init() returns -ENOSPC, hence the probe aborts silently. > >>>>> > >>>>> Is this already addressed? > >>>> > >>>> Haven't heard about this one before. What kernel did you last use that > >>>> worked? > >>> > >>> I'm guessing you just need to update the maximum number of policies: > >>> > >>> /* > >>> * Maximum number of blkcg policies allowed to be registered concurrently. > >>> * Defined here to simplify include dependency. > >>> */ > >>> #define BLKCG_MAX_POLS 3 > >> > >> That is my guess too, hence the suggestion to try and disable the > >> iolatency policy. Just tried here without, and it works, rebooting > >> with to verify that we're running out of policy slots. > > > > Functions calling this function: blkcg_policy_register > > > > File Function Line > > 0 block/bfq-iosched.c bfq_init 5675 ret = > > blkcg_policy_register(&blkcg_pol > > icy_bfq); > > 1 block/blk-iolatency.c iolatency_init 946 return > > blkcg_policy_register(&blkcg_pol > > icy_iolatency); > > 2 block/blk-throttle.c throtl_init 2511 return > > blkcg_policy_register(&blkcg_pol > > icy_throtl); > > 3 block/cfq-iosched.c cfq_init 4869 ret = > > blkcg_policy_register(&blkcg_pol > > icy_cfq); > > > > And then there were 4... > > Exactly. I'd bump it to 5 to leave room for one more, if we have to grow it > again, probably worth it to make it dynamic. So for, not really needed. Takashi, > can verify that the below fixes it up for you? Yes, it works. Tested-by: Takashi Iwai Thanks! Takashi