| Message ID | 20210303115740.127001-4-jefflexu@linux.alibaba.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | dm: support polling | expand |
On Wed, Mar 03 2021 at 6:57am -0500, Jeffle Xu <jefflexu@linux.alibaba.com> wrote: > ->poll_fn was introduced in commit ea435e1b9392 ("block: add a poll_fn > callback to struct request_queue") to support bio-based queues such as > nvme multipath, but was later removed in commit 529262d56dbe ("block: > remove ->poll_fn"). > > Given commit c62b37d96b6e ("block: move ->make_request_fn to struct > block_device_operations") restore the possibility of bio-based IO > polling support by adding an ->poll method to gendisk->fops. > > Make blk_mq_poll() specific to blk-mq, while blk_bio_poll() is > originally a copy from blk_mq_poll(), and is specific to bio-based > polling. Currently hybrid polling is not supported by bio-based polling. > > Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> > --- > block/blk-core.c | 58 ++++++++++++++++++++++++++++++++++++++++++ > block/blk-mq.c | 22 +--------------- > include/linux/blk-mq.h | 1 + > include/linux/blkdev.h | 1 + > 4 files changed, 61 insertions(+), 21 deletions(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index fc60ff208497..6d7d53030d7c 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -1119,6 +1119,64 @@ blk_qc_t submit_bio(struct bio *bio) > } > EXPORT_SYMBOL(submit_bio); > > + Minor nit: Extra empty new line here? ^ Otherwise, looks good (I like the end result of blk-mq and bio-based polling being decoupled like hch suggested). Reviewed-by: Mike Snitzer <snitzer@redhat.com> > +static int blk_bio_poll(struct request_queue *q, blk_qc_t cookie, bool spin) > +{ > + long state; > + struct gendisk *disk = queue_to_disk(q); > + > + state = current->state; > + do { > + int ret; > + > + ret = disk->fops->poll(q, cookie); > + if (ret > 0) { > + __set_current_state(TASK_RUNNING); > + return ret; > + } > + > + if (signal_pending_state(state, current)) > + __set_current_state(TASK_RUNNING); > + > + if (current->state == TASK_RUNNING) > + return 1; > + if (ret < 0 || !spin) > + break; > + cpu_relax(); > + } while (!need_resched()); > + > + __set_current_state(TASK_RUNNING); > + return 0; > +} > + > +/** > + * blk_poll - poll for IO completions > + * @q: the queue > + * @cookie: cookie passed back at IO submission time > + * @spin: whether to spin for completions > + * > + * Description: > + * Poll for completions on the passed in queue. Returns number of > + * completed entries found. If @spin is true, then blk_poll will continue > + * looping until at least one completion is found, unless the task is > + * otherwise marked running (or we need to reschedule). > + */ > +int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) > +{ > + if (!blk_qc_t_valid(cookie) || > + !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) > + return 0; > + > + if (current->plug) > + blk_flush_plug_list(current->plug, false); > + > + if (queue_is_mq(q)) > + return blk_mq_poll(q, cookie, spin); > + else > + return blk_bio_poll(q, cookie, spin); > +} > +EXPORT_SYMBOL_GPL(blk_poll); > + > /** > * blk_cloned_rq_check_limits - Helper function to check a cloned request > * for the new queue limits > diff --git a/block/blk-mq.c b/block/blk-mq.c > index d4d7c1caa439..214fa30b460a 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -3852,30 +3852,11 @@ static bool blk_mq_poll_hybrid(struct request_queue *q, > return blk_mq_poll_hybrid_sleep(q, rq); > } > > -/** > - * blk_poll - poll for IO completions > - * @q: the queue > - * @cookie: cookie passed back at IO submission time > - * @spin: whether to spin for completions > - * > - * Description: > - * Poll for completions on the passed in queue. Returns number of > - * completed entries found. If @spin is true, then blk_poll will continue > - * looping until at least one completion is found, unless the task is > - * otherwise marked running (or we need to reschedule). > - */ > -int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) > +int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin) > { > struct blk_mq_hw_ctx *hctx; > long state; > > - if (!blk_qc_t_valid(cookie) || > - !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) > - return 0; > - > - if (current->plug) > - blk_flush_plug_list(current->plug, false); > - > hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)]; > > /* > @@ -3917,7 +3898,6 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) > __set_current_state(TASK_RUNNING); > return 0; > } > -EXPORT_SYMBOL_GPL(blk_poll); > > unsigned int blk_mq_rq_cpu(struct request *rq) > { > diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h > index 2c473c9b8990..6a7b693b9917 100644 > --- a/include/linux/blk-mq.h > +++ b/include/linux/blk-mq.h > @@ -615,6 +615,7 @@ static inline void blk_rq_bio_prep(struct request *rq, struct bio *bio, > } > > blk_qc_t blk_mq_submit_bio(struct bio *bio); > +int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin); > void blk_mq_hctx_set_fq_lock_class(struct blk_mq_hw_ctx *hctx, > struct lock_class_key *key); > > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index b81a9fe015ab..9dc83c30e7bc 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -1866,6 +1866,7 @@ static inline void blk_ksm_unregister(struct request_queue *q) { } > > struct block_device_operations { > blk_qc_t (*submit_bio) (struct bio *bio); > + int (*poll)(struct request_queue *q, blk_qc_t cookie); > int (*open) (struct block_device *, fmode_t); > void (*release) (struct gendisk *, fmode_t); > int (*rw_page)(struct block_device *, sector_t, struct page *, unsigned int); > -- > 2.27.0 > -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel
On 3/11/21 6:01 AM, Mike Snitzer wrote: > On Wed, Mar 03 2021 at 6:57am -0500, > Jeffle Xu <jefflexu@linux.alibaba.com> wrote: > >> ->poll_fn was introduced in commit ea435e1b9392 ("block: add a poll_fn >> callback to struct request_queue") to support bio-based queues such as >> nvme multipath, but was later removed in commit 529262d56dbe ("block: >> remove ->poll_fn"). >> >> Given commit c62b37d96b6e ("block: move ->make_request_fn to struct >> block_device_operations") restore the possibility of bio-based IO >> polling support by adding an ->poll method to gendisk->fops. >> >> Make blk_mq_poll() specific to blk-mq, while blk_bio_poll() is >> originally a copy from blk_mq_poll(), and is specific to bio-based >> polling. Currently hybrid polling is not supported by bio-based polling. >> >> Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> >> --- >> block/blk-core.c | 58 ++++++++++++++++++++++++++++++++++++++++++ >> block/blk-mq.c | 22 +--------------- >> include/linux/blk-mq.h | 1 + >> include/linux/blkdev.h | 1 + >> 4 files changed, 61 insertions(+), 21 deletions(-) >> >> diff --git a/block/blk-core.c b/block/blk-core.c >> index fc60ff208497..6d7d53030d7c 100644 >> --- a/block/blk-core.c >> +++ b/block/blk-core.c >> @@ -1119,6 +1119,64 @@ blk_qc_t submit_bio(struct bio *bio) >> } >> EXPORT_SYMBOL(submit_bio); >> >> + > > Minor nit: Extra empty new line here? ^ Regards. Thanks. > > Otherwise, looks good (I like the end result of blk-mq and bio-based > polling being decoupled like hch suggested). > > Reviewed-by: Mike Snitzer <snitzer@redhat.com> > >> +static int blk_bio_poll(struct request_queue *q, blk_qc_t cookie, bool spin) >> +{ >> + long state; >> + struct gendisk *disk = queue_to_disk(q); >> + >> + state = current->state; >> + do { >> + int ret; >> + >> + ret = disk->fops->poll(q, cookie); >> + if (ret > 0) { >> + __set_current_state(TASK_RUNNING); >> + return ret; >> + } >> + >> + if (signal_pending_state(state, current)) >> + __set_current_state(TASK_RUNNING); >> + >> + if (current->state == TASK_RUNNING) >> + return 1; >> + if (ret < 0 || !spin) >> + break; >> + cpu_relax(); >> + } while (!need_resched()); >> + >> + __set_current_state(TASK_RUNNING); >> + return 0; >> +} >> + >> +/** >> + * blk_poll - poll for IO completions >> + * @q: the queue >> + * @cookie: cookie passed back at IO submission time >> + * @spin: whether to spin for completions >> + * >> + * Description: >> + * Poll for completions on the passed in queue. Returns number of >> + * completed entries found. If @spin is true, then blk_poll will continue >> + * looping until at least one completion is found, unless the task is >> + * otherwise marked running (or we need to reschedule). >> + */ >> +int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) >> +{ >> + if (!blk_qc_t_valid(cookie) || >> + !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) >> + return 0; >> + >> + if (current->plug) >> + blk_flush_plug_list(current->plug, false); >> + >> + if (queue_is_mq(q)) >> + return blk_mq_poll(q, cookie, spin); >> + else >> + return blk_bio_poll(q, cookie, spin); >> +} >> +EXPORT_SYMBOL_GPL(blk_poll); >> + >> /** >> * blk_cloned_rq_check_limits - Helper function to check a cloned request >> * for the new queue limits >> diff --git a/block/blk-mq.c b/block/blk-mq.c >> index d4d7c1caa439..214fa30b460a 100644 >> --- a/block/blk-mq.c >> +++ b/block/blk-mq.c >> @@ -3852,30 +3852,11 @@ static bool blk_mq_poll_hybrid(struct request_queue *q, >> return blk_mq_poll_hybrid_sleep(q, rq); >> } >> >> -/** >> - * blk_poll - poll for IO completions >> - * @q: the queue >> - * @cookie: cookie passed back at IO submission time >> - * @spin: whether to spin for completions >> - * >> - * Description: >> - * Poll for completions on the passed in queue. Returns number of >> - * completed entries found. If @spin is true, then blk_poll will continue >> - * looping until at least one completion is found, unless the task is >> - * otherwise marked running (or we need to reschedule). >> - */ >> -int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) >> +int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin) >> { >> struct blk_mq_hw_ctx *hctx; >> long state; >> >> - if (!blk_qc_t_valid(cookie) || >> - !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) >> - return 0; >> - >> - if (current->plug) >> - blk_flush_plug_list(current->plug, false); >> - >> hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)]; >> >> /* >> @@ -3917,7 +3898,6 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) >> __set_current_state(TASK_RUNNING); >> return 0; >> } >> -EXPORT_SYMBOL_GPL(blk_poll); >> >> unsigned int blk_mq_rq_cpu(struct request *rq) >> { >> diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h >> index 2c473c9b8990..6a7b693b9917 100644 >> --- a/include/linux/blk-mq.h >> +++ b/include/linux/blk-mq.h >> @@ -615,6 +615,7 @@ static inline void blk_rq_bio_prep(struct request *rq, struct bio *bio, >> } >> >> blk_qc_t blk_mq_submit_bio(struct bio *bio); >> +int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin); >> void blk_mq_hctx_set_fq_lock_class(struct blk_mq_hw_ctx *hctx, >> struct lock_class_key *key); >> >> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h >> index b81a9fe015ab..9dc83c30e7bc 100644 >> --- a/include/linux/blkdev.h >> +++ b/include/linux/blkdev.h >> @@ -1866,6 +1866,7 @@ static inline void blk_ksm_unregister(struct request_queue *q) { } >> >> struct block_device_operations { >> blk_qc_t (*submit_bio) (struct bio *bio); >> + int (*poll)(struct request_queue *q, blk_qc_t cookie); >> int (*open) (struct block_device *, fmode_t); >> void (*release) (struct gendisk *, fmode_t); >> int (*rw_page)(struct block_device *, sector_t, struct page *, unsigned int); >> -- >> 2.27.0 >> > > -- > dm-devel mailing list > dm-devel@redhat.com > https://listman.redhat.com/mailman/listinfo/dm-devel >
diff --git a/block/blk-core.c b/block/blk-core.c index fc60ff208497..6d7d53030d7c 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1119,6 +1119,64 @@ blk_qc_t submit_bio(struct bio *bio) } EXPORT_SYMBOL(submit_bio); + +static int blk_bio_poll(struct request_queue *q, blk_qc_t cookie, bool spin) +{ + long state; + struct gendisk *disk = queue_to_disk(q); + + state = current->state; + do { + int ret; + + ret = disk->fops->poll(q, cookie); + if (ret > 0) { + __set_current_state(TASK_RUNNING); + return ret; + } + + if (signal_pending_state(state, current)) + __set_current_state(TASK_RUNNING); + + if (current->state == TASK_RUNNING) + return 1; + if (ret < 0 || !spin) + break; + cpu_relax(); + } while (!need_resched()); + + __set_current_state(TASK_RUNNING); + return 0; +} + +/** + * blk_poll - poll for IO completions + * @q: the queue + * @cookie: cookie passed back at IO submission time + * @spin: whether to spin for completions + * + * Description: + * Poll for completions on the passed in queue. Returns number of + * completed entries found. If @spin is true, then blk_poll will continue + * looping until at least one completion is found, unless the task is + * otherwise marked running (or we need to reschedule). + */ +int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) +{ + if (!blk_qc_t_valid(cookie) || + !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) + return 0; + + if (current->plug) + blk_flush_plug_list(current->plug, false); + + if (queue_is_mq(q)) + return blk_mq_poll(q, cookie, spin); + else + return blk_bio_poll(q, cookie, spin); +} +EXPORT_SYMBOL_GPL(blk_poll); + /** * blk_cloned_rq_check_limits - Helper function to check a cloned request * for the new queue limits diff --git a/block/blk-mq.c b/block/blk-mq.c index d4d7c1caa439..214fa30b460a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3852,30 +3852,11 @@ static bool blk_mq_poll_hybrid(struct request_queue *q, return blk_mq_poll_hybrid_sleep(q, rq); } -/** - * blk_poll - poll for IO completions - * @q: the queue - * @cookie: cookie passed back at IO submission time - * @spin: whether to spin for completions - * - * Description: - * Poll for completions on the passed in queue. Returns number of - * completed entries found. If @spin is true, then blk_poll will continue - * looping until at least one completion is found, unless the task is - * otherwise marked running (or we need to reschedule). - */ -int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) +int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin) { struct blk_mq_hw_ctx *hctx; long state; - if (!blk_qc_t_valid(cookie) || - !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) - return 0; - - if (current->plug) - blk_flush_plug_list(current->plug, false); - hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)]; /* @@ -3917,7 +3898,6 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) __set_current_state(TASK_RUNNING); return 0; } -EXPORT_SYMBOL_GPL(blk_poll); unsigned int blk_mq_rq_cpu(struct request *rq) { diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 2c473c9b8990..6a7b693b9917 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -615,6 +615,7 @@ static inline void blk_rq_bio_prep(struct request *rq, struct bio *bio, } blk_qc_t blk_mq_submit_bio(struct bio *bio); +int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin); void blk_mq_hctx_set_fq_lock_class(struct blk_mq_hw_ctx *hctx, struct lock_class_key *key); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index b81a9fe015ab..9dc83c30e7bc 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1866,6 +1866,7 @@ static inline void blk_ksm_unregister(struct request_queue *q) { } struct block_device_operations { blk_qc_t (*submit_bio) (struct bio *bio); + int (*poll)(struct request_queue *q, blk_qc_t cookie); int (*open) (struct block_device *, fmode_t); void (*release) (struct gendisk *, fmode_t); int (*rw_page)(struct block_device *, sector_t, struct page *, unsigned int);
->poll_fn was introduced in commit ea435e1b9392 ("block: add a poll_fn callback to struct request_queue") to support bio-based queues such as nvme multipath, but was later removed in commit 529262d56dbe ("block: remove ->poll_fn"). Given commit c62b37d96b6e ("block: move ->make_request_fn to struct block_device_operations") restore the possibility of bio-based IO polling support by adding an ->poll method to gendisk->fops. Make blk_mq_poll() specific to blk-mq, while blk_bio_poll() is originally a copy from blk_mq_poll(), and is specific to bio-based polling. Currently hybrid polling is not supported by bio-based polling. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> --- block/blk-core.c | 58 ++++++++++++++++++++++++++++++++++++++++++ block/blk-mq.c | 22 +--------------- include/linux/blk-mq.h | 1 + include/linux/blkdev.h | 1 + 4 files changed, 61 insertions(+), 21 deletions(-)