From: Eric Wheeler <stable@lists.ewheeler.net>
To: Sasha Levin <sashal@kernel.org>
Cc: Paolo Valente <paolo.valente@linaro.org>,
Jens Axboe <axboe@kernel.dk>,
"open list:BFQ I/O SCHEDULER" <linux-block@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
Eric Wheeler <bfq@linux.ewheeler.net>,
stable@vger.kernel.org
Subject: Re: [PATCH] bfq: backport: update internal depth state when queue depth changes
Date: Fri, 10 May 2019 23:17:20 +0000 (UTC) [thread overview]
Message-ID: <alpine.LRH.2.11.1905102312220.4789@mx.ewheeler.net> (raw)
In-Reply-To: <20190510201855.GB14410@sasha-vm>
On Fri, 10 May 2019, Sasha Levin wrote:
> On Fri, May 10, 2019 at 10:56:32AM -0700, Eric Wheeler wrote:
> >From: Jens Axboe <axboe@kernel.dk>
> >
> >commit 77f1e0a52d26242b6c2dba019f6ebebfb9ff701e upstream
> >
> >A previous commit moved the shallow depth and BFQ depth map calculations
> >to be done at init time, moving it outside of the hotter IO path. This
> >potentially causes hangs if the users changes the depth of the scheduler
> >map, by writing to the 'nr_requests' sysfs file for that device.
> >
> >Add a blk-mq-sched hook that allows blk-mq to inform the scheduler if
> >the depth changes, so that the scheduler can update its internal state.
> >
> >Signed-off-by: Eric Wheeler <bfq@linux.ewheeler.net>
> >Tested-by: Kai Krakow <kai@kaishome.de>
> >Reported-by: Paolo Valente <paolo.valente@linaro.org>
> >Fixes: f0635b8a416e ("bfq: calculate shallow depths at init time")
> >Signed-off-by: Jens Axboe <axboe@kernel.dk>
> >Cc: stable@vger.kernel.org
>
> I wasn't clear on what was backported here, so I've queued the upstream
> version on 4.19 and 4.14, it doesn't seem to be relevant to older
> branches.
Thanks Sasha. We needed it for 4.19, I wasn't sure how far it would patch
back so I left the version off. BFQ was merged in 4.12 iirc, so if it
patched against 4.14, then 4.19 and 4.14 are the only ones that need it.
--
Eric Wheeler
>
> --
> Thanks,
> Sasha
>
next prev parent reply other threads:[~2019-05-10 23:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-10 17:56 [PATCH] bfq: backport: update internal depth state when queue depth changes Eric Wheeler
2019-05-10 20:18 ` Sasha Levin
2019-05-10 23:17 ` Eric Wheeler [this message]
2019-05-10 23:58 ` Holger Hoffstätte
2019-05-13 7:03 ` Greg KH
2019-05-13 13:09 ` Sasha Levin
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