| Message ID | 1478034531-28559-6-git-send-email-axboe@fb.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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.. > /** > + * 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? > +++ 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? -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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.
On Wed, Nov 02, 2016 at 09:02:08AM -0600, Jens Axboe wrote: > 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. A lot of block code uses this kind of setters so I _think_ it complies with the overall style. But I have no strong opinion on this either... Byte, Johannes
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 >
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,
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> --- block/blk-settings.c | 12 ++++++++++++ drivers/scsi/scsi.c | 3 +++ include/linux/blkdev.h | 11 +++++++++++ 3 files changed, 26 insertions(+)