From: Jan Kara <jack@suse.cz>
To: Jens Axboe <axboe@fb.com>
Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
jack@suse.cz, hch@lst.de
Subject: Re: [PATCH 5/8] block: add code to track actual device queue depth
Date: Sat, 5 Nov 2016 23:37:44 +0100 [thread overview]
Message-ID: <20161105223744.GF32353@quack2.suse.cz> (raw)
In-Reply-To: <1478034531-28559-6-git-send-email-axboe@fb.com>
On Tue 01-11-16 15:08:48, 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
> drivers can call to more closely inform the block layer of the
> real queue depth.
>
> Signed-off-by: Jens Axboe <axboe@fb.com>
The patch looks good to me. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> ---
> block/blk-settings.c | 12 ++++++++++++
> drivers/scsi/scsi.c | 3 +++
> include/linux/blkdev.h | 11 +++++++++++
> 3 files changed, 26 insertions(+)
>
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index 55369a65dea2..9cf053759363 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -837,6 +837,18 @@ void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
> EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
>
> /**
> + * 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);
> +
> +/**
> * blk_queue_write_cache - configure queue's write cache
> * @q: the request queue for the device
> * @wc: write back cache on or off
> diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
> index 1deb6adc411f..75455d4dab68 100644
> --- a/drivers/scsi/scsi.c
> +++ 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;
> }
> EXPORT_SYMBOL(scsi_change_queue_depth);
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 8396da2bb698..0c677fb35ce4 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -405,6 +405,8 @@ struct request_queue {
> struct blk_mq_ctx __percpu *queue_ctx;
> unsigned int nr_queues;
>
> + unsigned int queue_depth;
> +
> /* hw dispatch queues */
> struct blk_mq_hw_ctx **queue_hw_ctx;
> unsigned int nr_hw_queues;
> @@ -777,6 +779,14 @@ static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
> return false;
> }
>
> +static inline unsigned int blk_queue_depth(struct request_queue *q)
> +{
> + if (q->queue_depth)
> + return q->queue_depth;
> +
> + return q->nr_requests;
> +}
> +
> /*
> * q->prep_rq_fn return values
> */
> @@ -1093,6 +1103,7 @@ extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
> extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
> extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
> extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
> +extern void blk_set_queue_depth(struct request_queue *q, unsigned int depth);
> extern void blk_set_default_limits(struct queue_limits *lim);
> extern void blk_set_stacking_limits(struct queue_limits *lim);
> extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
> --
> 2.7.4
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2016-11-05 22:37 UTC|newest]
Thread overview: 41+ 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
2016-11-02 16:40 ` Johannes Thumshirn
2016-11-05 22:37 ` Jan Kara [this message]
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
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