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 8117FC6778D for ; Tue, 11 Sep 2018 16:51:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A63120839 for ; Tue, 11 Sep 2018 16:51:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A63120839 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 S1728067AbeIKVvj (ORCPT ); Tue, 11 Sep 2018 17:51:39 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:51974 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726622AbeIKVvi (ORCPT ); Tue, 11 Sep 2018 17:51:38 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3E6927DAC2; Tue, 11 Sep 2018 16:51:28 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (segfault.boston.devel.redhat.com [10.19.60.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 11ADC10073D6; Tue, 11 Sep 2018 16:51:28 +0000 (UTC) From: Jeff Moyer To: Jens Axboe Cc: Takashi Iwai , Paolo Valente , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [REGRESSION] bfq probe failed on 4.19-rc3 References: <8b5a7dc9-2dc1-16ee-4b05-a72eb6680c77@kernel.dk> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Tue, 11 Sep 2018 12:51:27 -0400 In-Reply-To: (Jens Axboe's message of "Tue, 11 Sep 2018 10:49:05 -0600") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 11 Sep 2018 16:51:28 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 11 Sep 2018 16:51:28 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jmoyer@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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... -Jeff