From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [REGRESSION] bfq probe failed on 4.19-rc3 To: Takashi Iwai Cc: Paolo Valente , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <8b5a7dc9-2dc1-16ee-4b05-a72eb6680c77@kernel.dk> From: Jens Axboe Message-ID: <7fcd013b-b87a-a603-d010-02d70d6e559d@kernel.dk> Date: Tue, 11 Sep 2018 10:20:23 -0600 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 List-ID: On 9/11/18 10:16 AM, Takashi Iwai wrote: > On Tue, 11 Sep 2018 18:11:43 +0200, > Takashi Iwai wrote: >> >> On Tue, 11 Sep 2018 18:09:44 +0200, >> Jens Axboe wrote: >>> >>> 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? >> >> IIRC, 4.18 worked fine. Let me see whether I have a backup... > > Confirmed that 4.18 worked. It's also with CONFIG_IOSCHED_BFQ=y and > CONFIG_BFQ_GROUP_IOSCHED=y. > > And, 4.19-rc3 with CONFIG_BFQ_GROUP_IOSCHED=n seems working, too (as > expected from the error above). > > > (BTW I'll have to leave from this machine now. For any further > inquiry, I'll check tomorrow, sorry.) Very odd. Maybe try without CONFIG_BLK_CGROUP_IOLATENCY being set? I'll try and reproduce it here. -- Jens Axboe