linux-kernel - [RFC PATCH 0/2] improve io scheduler callback triggering

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Message-ID: <20210827124100.98112-1-Niklas.Cassel@wdc.com>
Date:   Fri, 27 Aug 2021 12:41:22 +0000
From:   Niklas Cassel <Niklas.Cassel@....com>
To:     Jens Axboe <axboe@...nel.dk>
CC:     Bart Van Assche <bvanassche@....org>,
        Damien Le Moal <Damien.LeMoal@....com>,
        Paolo Valente <paolo.valente@...aro.org>,
        Niklas Cassel <Niklas.Cassel@....com>,
        "linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH 0/2] improve io scheduler callback triggering

From: Niklas Cassel <niklas.cassel@....com>

Recently, there were some extra "dummy" data added into mq-deadline
rq->elv.priv, that was there for the solve purpose of working around
shortcomings in blk-mq (which called the scheduler callbacks even
for requests that bypassed the scheduler).

Fix blk-mq to behave in a more sane way with regards to scheduler
callback triggering, and remove the now unneeded rq->elv.priv magic.

BFQ should be able to perform a similar cleanup, and should be able
to drop this comment from the code:
https://github.com/torvalds/linux/blob/master/block/bfq-iosched.c#L6456-L6462

Considering that I'm quite unfamiliar with the BFQ code, I'd rather
someone who is a bit more familiar with BFQ performs that cleanup.


Kind regards,
Niklas

Niklas Cassel (2):
  blk-mq: don't call callbacks for requests that bypassed the scheduler
  Revert "mq-deadline: Fix request accounting"

 block/blk-mq-sched.c   | 20 ++++++++++++++++++++
 block/blk-mq.c         | 13 -------------
 block/mq-deadline.c    | 16 +++++-----------
 include/linux/blkdev.h |  3 ++-
 4 files changed, 27 insertions(+), 25 deletions(-)

-- 
2.31.1