From: Jens Axboe <axboe@fb.com>
To: Christoph Hellwig <hch@lst.de>
Cc: <axboe@kernel.dk>, <linux-kernel@vger.kernel.org>,
<linux-fsdevel@vger.kernel.org>, <linux-block@vger.kernel.org>,
<jack@suse.cz>
Subject: Re: [PATCH 5/8] block: add code to track actual device queue depth
Date: Wed, 2 Nov 2016 09:02:08 -0600 [thread overview]
Message-ID: <c2295532-22a0-0c70-d6f9-7e13e76a1906@fb.com> (raw)
In-Reply-To: <20161102145908.GI13964@lst.de>
On 11/02/2016 08:59 AM, Christoph Hellwig wrote:
> On Tue, Nov 01, 2016 at 03:08:48PM -0600, Jens Axboe wrote:
>> For blk-mq, ->nr_requests does track queue depth, at least at init
>> time. But for the older queue paths, it's simply a soft setting.
>> On top of that, it's generally larger than the hardware setting
>> on purpose, to allow backup of requests for merging.
>>
>> Fill a hole in struct request with a 'queue_depth' member, that
>
> That would be struct request_queue..
Good catch, will fix.
>> /**
>> + * blk_set_queue_depth - tell the block layer about the device queue depth
>> + * @q: the request queue for the device
>> + * @depth: queue depth
>> + *
>> + */
>> +void blk_set_queue_depth(struct request_queue *q, unsigned int depth)
>> +{
>> + q->queue_depth = depth;
>> +}
>> +EXPORT_SYMBOL(blk_set_queue_depth);
>
> Do we really need this wrapper?
Not necessarily, just seems like a nicer API than manually setting the
field. Not a big deal to me, though.
>> +++ b/drivers/scsi/scsi.c
>> @@ -621,6 +621,9 @@ int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
>> wmb();
>> }
>>
>> + if (sdev->request_queue)
>> + blk_set_queue_depth(sdev->request_queue, depth);
>> +
>> return sdev->queue_depth;
>
> Can we kill the scsi_device queue_depth member and just always use
> the request_queue one?
Yes. I'd prefer that we do that through the SCSI tree, once this is in
though.
--
Jens Axboe
next prev parent reply other threads:[~2016-11-02 15:02 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-01 21:08 [PATCHSET] Throttled buffered writeback Jens Axboe
2016-11-01 21:08 ` [PATCH 1/8] block: add WRITE_BACKGROUND Jens Axboe
2016-11-02 14:55 ` Christoph Hellwig
2016-11-02 16:22 ` Jens Axboe
2016-11-05 22:27 ` Jan Kara
2016-11-01 21:08 ` [PATCH 2/8] writeback: add wbc_to_write_flags() Jens Axboe
2016-11-02 14:56 ` Christoph Hellwig
2016-11-01 21:08 ` [PATCH 3/8] writeback: mark background writeback as such Jens Axboe
2016-11-02 14:56 ` Christoph Hellwig
2016-11-05 22:26 ` Jan Kara
2016-11-01 21:08 ` [PATCH 4/8] writeback: track if we're sleeping on progress in balance_dirty_pages() Jens Axboe
2016-11-02 14:57 ` Christoph Hellwig
2016-11-02 14:59 ` Jens Axboe
2016-11-08 13:02 ` Jan Kara
2016-11-01 21:08 ` [PATCH 5/8] block: add code to track actual device queue depth Jens Axboe
2016-11-02 14:59 ` Christoph Hellwig
2016-11-02 15:02 ` Jens Axboe [this message]
2016-11-02 16:40 ` Johannes Thumshirn
2016-11-05 22:37 ` Jan Kara
2016-11-01 21:08 ` [PATCH 6/8] block: add scalable completion tracking of requests Jens Axboe
2016-11-08 13:30 ` Jan Kara
2016-11-08 15:25 ` Jens Axboe
2016-11-09 9:01 ` Jan Kara
2016-11-09 16:09 ` Jens Axboe
2016-11-09 19:52 ` Jens Axboe
2016-11-10 19:38 ` Jan Kara
2016-11-12 5:19 ` Jens Axboe
2016-11-01 21:08 ` [PATCH 7/8] blk-wbt: add general throttling mechanism Jens Axboe
2016-11-08 13:39 ` Jan Kara
2016-11-08 15:41 ` Jens Axboe
2016-11-09 8:40 ` Jan Kara
2016-11-09 16:07 ` Jens Axboe
2016-11-09 19:52 ` Jens Axboe
2016-11-10 19:36 ` Jan Kara
2016-11-10 0:00 ` Dave Chinner
2016-11-01 21:08 ` [PATCH 8/8] block: hook up writeback throttling Jens Axboe
2016-11-08 13:42 ` Jan Kara
2016-11-08 15:16 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2016-10-26 20:52 [PATCHSET] block: buffered " Jens Axboe
2016-10-26 20:52 ` [PATCH 5/8] block: add code to track actual device queue depth Jens Axboe
2016-09-07 14:46 [PATCH 0/8] Throttled background buffered writeback v7 Jens Axboe
2016-09-07 14:46 ` [PATCH 5/8] block: add code to track actual device queue depth Jens Axboe
2016-08-31 17:05 [PATCHSET v6] Throttled background buffered writeback Jens Axboe
2016-08-31 17:05 ` [PATCH 5/8] block: add code to track actual device queue depth Jens Axboe
2016-04-26 15:55 [PATCHSET v5] Make background writeback great again for the first time Jens Axboe
2016-04-26 15:55 ` [PATCH 5/8] block: add code to track actual device queue depth Jens Axboe
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