From: Jan Kara <jack@suse.cz>
To: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>,
linux-block@vger.kernel.org,
Paolo Valente <paolo.valente@linaro.org>
Subject: Re: [PATCH 1/8] block: Provide icq in request allocation data
Date: Tue, 23 Nov 2021 23:30:45 +0100 [thread overview]
Message-ID: <20211123223045.GC8583@quack2.suse.cz> (raw)
In-Reply-To: <4cae86cc-e484-cb91-7189-0afbe84f69b9@kernel.dk>
On Tue 23-11-21 09:06:47, Jens Axboe wrote:
> On 11/23/21 3:29 AM, Jan Kara wrote:
> > Currently we lookup ICQ only after the request is allocated. However BFQ
> > will want to decide how many scheduler tags it allows a given bfq queue
> > (effectively a process) to consume based on cgroup weight. So lookup ICQ
> > earlier and provide it in struct blk_mq_alloc_data so that BFQ can use
> > it.
>
> I've been trying to clean this path up a bit, since I don't like having
> something that just one scheduler needs in the fast path. See:
>
> https://git.kernel.dk/cgit/linux-block/commit/?h=perf-wip&id=f1f8191a8f9a0cdcd5ad99dfd7e551e8f444bec5
>
> Would be better if we could avoid adding io_cq to blk_mq_alloc_data for
> that reason, would it be possible to hide this away in the sched code
> instead on top of the above?
Understood. We could certainly handle ICQ allocation & assignment only inside
BFQ. Just this would mean we would need to lookup ICQ once in
bfq_limit_depth() and then second time in bfq_prepare_request(). I guess
not a huge deal given the amount of work BFQ does for each request anyway.
So can I pull the above commit into the series and rebase this patch on top
of it?
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2021-11-23 22:30 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-23 10:29 [PATCH 0/8 v4] bfq: Limit number of allocated scheduler tags per cgroup Jan Kara
2021-11-23 10:29 ` [PATCH 1/8] block: Provide icq in request allocation data Jan Kara
2021-11-23 16:06 ` Jens Axboe
2021-11-23 22:30 ` Jan Kara [this message]
2021-11-23 23:10 ` Jens Axboe
2021-11-23 10:29 ` [PATCH 2/8] bfq: Track number of allocated requests in bfq_entity Jan Kara
2021-11-23 10:29 ` [PATCH 3/8] bfq: Store full bitmap depth in bfq_data Jan Kara
2021-11-23 10:29 ` [PATCH 4/8] bfq: Limit number of requests consumed by each cgroup Jan Kara
2021-11-23 10:29 ` [PATCH 5/8] bfq: Limit waker detection in time Jan Kara
2021-11-23 10:29 ` [PATCH 6/8] bfq: Provide helper to generate bfqq name Jan Kara
2021-11-23 10:29 ` [PATCH 7/8] bfq: Log waker detections Jan Kara
2021-11-23 10:29 ` [PATCH 8/8] bfq: Do not let waker requests skip proper accounting Jan Kara
-- strict thread matches above, loose matches on Subject: below --
2021-10-06 17:31 [PATCH 0/8 v3] bfq: Limit number of allocated scheduler tags per cgroup Jan Kara
2021-10-06 17:31 ` [PATCH 1/8] block: Provide icq in request allocation data Jan Kara
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