From: Pavel Begunkov <asml.silence@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: axboe@kernel.dk, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com,
cgroups@vger.kernel.org, newella@fb.com, josef@toxicpanda.com,
ming.lei@redhat.com, bvanassche@acm.org
Subject: Re: [PATCHSET v2 block/for-5.8] iocost: improve use_delay and latency target handling
Date: Mon, 13 Apr 2020 21:49:12 +0300 [thread overview]
Message-ID: <5d2e4017-563b-4a2e-58d7-7af6e3183569@gmail.com> (raw)
In-Reply-To: <20200413170833.GD60335@mtj.duckdns.org>
On 13/04/2020 20:08, Tejun Heo wrote:
> On Mon, Apr 13, 2020 at 08:00:29PM +0300, Pavel Begunkov wrote:
>> On 13/04/2020 19:56, Pavel Begunkov wrote:
>>> On 13/04/2020 19:27, Tejun Heo wrote:
>>>> Changes from v1[1]
>>>>
>>>> * Dropped 0002-block-add-request-io_data_len.patch and updated to use
>>>> rq->stats_sectors instead as suggested by Pavel Begunkov.
>>>
>>> rq->stats_sectors is set only when there is QUEUE_FLAG_STATS, see
>>> blk_mq_start_request(). I don't see blk-iocost requiring it. Did I miss something?
>>
>> And there is no reason to not initialise it unconditionally.
>
> The updated patch turns on accounting when iocost is enabled on a queue.
Great. FWIW, if you don't really need accounting, it'd be IMHO more robust and
with less overhead just to do this ->stats_sectors assignment unconditionally.
>
> @@ -2267,6 +2295,7 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
> spin_lock_irq(&ioc->lock);
>
> if (enable) {
> + blk_stat_enable_accounting(ioc->rqos.q);
> blk_queue_flag_set(QUEUE_FLAG_RQ_ALLOC_TIME, ioc->rqos.q);
> ioc->enabled = true;
> } else {
>
> Thanks.
>
--
Pavel Begunkov
next prev parent reply other threads:[~2020-04-13 18:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-13 16:27 [PATCHSET v2 block/for-5.8] iocost: improve use_delay and latency target handling Tejun Heo
2020-04-13 16:27 ` [PATCH 1/4] blk-iocost: switch to fixed non-auto-decaying use_delay Tejun Heo
2020-04-13 16:27 ` [PATCH 2/4] blk-iocost: account for IO size when testing latencies Tejun Heo
2020-04-13 16:27 ` [PATCH 3/4] iocost_monitor: exit successfully if interval is zero Tejun Heo
2020-04-13 16:27 ` [PATCH 4/4] iocost_monitor: drop string wrap around numbers when outputting json Tejun Heo
2020-04-13 16:56 ` [PATCHSET v2 block/for-5.8] iocost: improve use_delay and latency target handling Pavel Begunkov
2020-04-13 17:00 ` Pavel Begunkov
2020-04-13 17:08 ` Tejun Heo
2020-04-13 18:49 ` Pavel Begunkov [this message]
2020-04-30 21:55 ` Jens Axboe
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