| Message ID | 20230424203329.2369688-9-bvanassche@acm.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mq-deadline: Improve support for zoned block devices | expand |
On Mon, Apr 24, 2023 at 01:33:28PM -0700, Bart Van Assche wrote: > Start dispatching from the start of a zone instead of from the starting > position of the most recently dispatched request. > > If a zoned write is requeued with an LBA that is lower than already > inserted zoned writes, make sure that it is submitted first. > > Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Ming Lei <ming.lei@redhat.com> > Signed-off-by: Bart Van Assche <bvanassche@acm.org> > --- > block/mq-deadline.c | 25 +++++++++++++++++++++++-- > 1 file changed, 23 insertions(+), 2 deletions(-) > > diff --git a/block/mq-deadline.c b/block/mq-deadline.c > index bf1dfe9fe9c9..2de6c63190d8 100644 > --- a/block/mq-deadline.c > +++ b/block/mq-deadline.c > @@ -156,13 +156,23 @@ deadline_latter_request(struct request *rq) > return NULL; > } > > -/* Return the first request for which blk_rq_pos() >= pos. */ > +/* > + * Return the first request for which blk_rq_pos() >= @pos. For zoned devices, > + * return the first request after the highest zone start <= @pos. > + */ > static inline struct request *deadline_from_pos(struct dd_per_prio *per_prio, > enum dd_data_dir data_dir, sector_t pos) > { > struct rb_node *node = per_prio->sort_list[data_dir].rb_node; > struct request *rq, *res = NULL; > > + if (!node) > + return NULL; > + > + rq = rb_entry_rq(node); > + if (blk_rq_is_seq_zoned_write(rq)) > + pos -= bdev_offset_from_zone_start(rq->q->disk->part0, pos); This looks a bit odd. I'd write this as: if (blk_rq_is_seq_zoned_write(rq)) pos = round_down(pos, rq->q->limits.chunk_sectors); > @@ -821,7 +833,16 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, > * set expire time and add to fifo list > */ > rq->fifo_time = jiffies + dd->fifo_expire[data_dir]; > - list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]); > + insert_before = &per_prio->fifo_list[data_dir]; > +#ifdef CONFIG_BLK_DEV_ZONED > + if (blk_rq_is_seq_zoned_write(rq)) { > + struct request *rq2 = deadline_latter_request(rq); > + > + if (rq2 && blk_rq_zone_no(rq2) == blk_rq_zone_no(rq)) > + insert_before = &rq2->queuelist; > + } > +#endif Why does this need an ifdef? Also can you please always add comments for these special cases? Same for the one above. > + list_add_tail(&rq->queuelist, insert_before); > } > } > ---end quoted text---
On 4/27/23 22:54, Christoph Hellwig wrote: > On Mon, Apr 24, 2023 at 01:33:28PM -0700, Bart Van Assche wrote: >> @@ -821,7 +833,16 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, >> * set expire time and add to fifo list >> */ >> rq->fifo_time = jiffies + dd->fifo_expire[data_dir]; >> - list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]); >> + insert_before = &per_prio->fifo_list[data_dir]; >> +#ifdef CONFIG_BLK_DEV_ZONED >> + if (blk_rq_is_seq_zoned_write(rq)) { >> + struct request *rq2 = deadline_latter_request(rq); >> + >> + if (rq2 && blk_rq_zone_no(rq2) == blk_rq_zone_no(rq)) >> + insert_before = &rq2->queuelist; >> + } >> +#endif > > Why does this need an ifdef? Because the blk_rq_zone_no() definition is surrounded with #ifdef CONFIG_BLK_DEV_ZONED / #endif. Without the #ifdef the above code would trigger a compilation error with CONFIG_BLK_DEV_ZONED=n. I have considered to add a definition of blk_rq_zone_no() for CONFIG_BLK_DEV_ZONED=n. I prefer not to do this because I think it's better to cause a compiler error if blk_rq_zone_no() is used in code that is also used for the CONFIG_BLK_DEV_ZONED=n case. > Also can you please always add comments for these special cases? Will do. Thanks, Bart.
On Fri, Apr 28, 2023 at 10:03:45AM -0700, Bart Van Assche wrote: > Because the blk_rq_zone_no() definition is surrounded with #ifdef > CONFIG_BLK_DEV_ZONED / #endif. Without the #ifdef the above code would > trigger a compilation error with CONFIG_BLK_DEV_ZONED=n. I have considered > to add a definition of blk_rq_zone_no() for CONFIG_BLK_DEV_ZONED=n. I > prefer not to do this because I think it's better to cause a compiler error > if blk_rq_zone_no() is used in code that is also used for the > CONFIG_BLK_DEV_ZONED=n case. Ok.
diff --git a/block/mq-deadline.c b/block/mq-deadline.c index bf1dfe9fe9c9..2de6c63190d8 100644 --- a/block/mq-deadline.c +++ b/block/mq-deadline.c @@ -156,13 +156,23 @@ deadline_latter_request(struct request *rq) return NULL; } -/* Return the first request for which blk_rq_pos() >= pos. */ +/* + * Return the first request for which blk_rq_pos() >= @pos. For zoned devices, + * return the first request after the highest zone start <= @pos. + */ static inline struct request *deadline_from_pos(struct dd_per_prio *per_prio, enum dd_data_dir data_dir, sector_t pos) { struct rb_node *node = per_prio->sort_list[data_dir].rb_node; struct request *rq, *res = NULL; + if (!node) + return NULL; + + rq = rb_entry_rq(node); + if (blk_rq_is_seq_zoned_write(rq)) + pos -= bdev_offset_from_zone_start(rq->q->disk->part0, pos); + while (node) { rq = rb_entry_rq(node); if (blk_rq_pos(rq) >= pos) { @@ -809,6 +819,8 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, list_add(&rq->queuelist, &per_prio->dispatch); rq->fifo_time = jiffies; } else { + struct list_head *insert_before; + deadline_add_rq_rb(per_prio, rq); if (rq_mergeable(rq)) { @@ -821,7 +833,16 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, * set expire time and add to fifo list */ rq->fifo_time = jiffies + dd->fifo_expire[data_dir]; - list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]); + insert_before = &per_prio->fifo_list[data_dir]; +#ifdef CONFIG_BLK_DEV_ZONED + if (blk_rq_is_seq_zoned_write(rq)) { + struct request *rq2 = deadline_latter_request(rq); + + if (rq2 && blk_rq_zone_no(rq2) == blk_rq_zone_no(rq)) + insert_before = &rq2->queuelist; + } +#endif + list_add_tail(&rq->queuelist, insert_before); } }
Start dispatching from the start of a zone instead of from the starting position of the most recently dispatched request. If a zoned write is requeued with an LBA that is lower than already inserted zoned writes, make sure that it is submitted first. Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> --- block/mq-deadline.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-)