| Message ID | 0ec9b1167d22966cdf77a1d5140499493ea888a2.1486408944.git.osandov@fb.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/06/2017 12:24 PM, Omar Sandoval wrote: > From: Omar Sandoval <osandov@fb.com> > > In blk_mq_sched_dispatch_requests(), we call blk_mq_sched_mark_restart() > after we dispatch requests left over on our hardware queue dispatch > list. This is so we'll go back and dispatch requests from the scheduler. > In this case, it's only necessary to restart the hardware queue that we > are running; there's no reason to run other hardware queues just because > we are using shared tags. > > So, split out blk_mq_sched_mark_restart() into two operations, one for > just the hardware queue and one for the whole request queue. The core > code uses both, and I/O schedulers may also want to use them. > > Signed-off-by: Omar Sandoval <osandov@fb.com> > --- > Patch based on block/for-next. > > block/blk-mq-sched.c | 2 +- > block/blk-mq-sched.h | 25 ++++++++++++++++++------- > block/blk-mq.c | 5 ++++- > 3 files changed, 23 insertions(+), 9 deletions(-) > > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c > index ee455e7cf9d8..7538565359ea 100644 > --- a/block/blk-mq-sched.c > +++ b/block/blk-mq-sched.c > @@ -201,7 +201,7 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) > * needing a restart in that case. > */ > if (!list_empty(&rq_list)) { > - blk_mq_sched_mark_restart(hctx); > + blk_mq_sched_mark_restart_hctx(hctx); > blk_mq_dispatch_rq_list(hctx, &rq_list); What if we dispatched nothing on this hardware queue, and it currently doesn't have any IO pending?
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index ee455e7cf9d8..7538565359ea 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -201,7 +201,7 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) * needing a restart in that case. */ if (!list_empty(&rq_list)) { - blk_mq_sched_mark_restart(hctx); + blk_mq_sched_mark_restart_hctx(hctx); blk_mq_dispatch_rq_list(hctx, &rq_list); } else if (!e || !e->type->ops.mq.dispatch_request) { blk_mq_flush_busy_ctxs(hctx, &rq_list); diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h index 5954859c8670..46788ef2b3db 100644 --- a/block/blk-mq-sched.h +++ b/block/blk-mq-sched.h @@ -121,16 +121,27 @@ static inline bool blk_mq_sched_has_work(struct blk_mq_hw_ctx *hctx) return false; } -static inline void blk_mq_sched_mark_restart(struct blk_mq_hw_ctx *hctx) +/* + * Mark a hardware queue as needing a restart. + */ +static inline void blk_mq_sched_mark_restart_hctx(struct blk_mq_hw_ctx *hctx) { - if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) { + if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state); - if (hctx->flags & BLK_MQ_F_TAG_SHARED) { - struct request_queue *q = hctx->queue; +} + +/* + * Mark a hardware queue and the request queue it belongs to as needing a + * restart. + */ +static inline void blk_mq_sched_mark_restart_queue(struct blk_mq_hw_ctx *hctx) +{ + struct request_queue *q = hctx->queue; - if (!test_bit(QUEUE_FLAG_RESTART, &q->queue_flags)) - set_bit(QUEUE_FLAG_RESTART, &q->queue_flags); - } + if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) { + set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state); + if (!test_bit(QUEUE_FLAG_RESTART, &q->queue_flags)) + set_bit(QUEUE_FLAG_RESTART, &q->queue_flags); } } diff --git a/block/blk-mq.c b/block/blk-mq.c index be183e6115a1..a494c0b589d5 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -937,7 +937,10 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list) * in case the needed IO completed right before we * marked the queue as needing a restart. */ - blk_mq_sched_mark_restart(hctx); + if (hctx->flags & BLK_MQ_F_TAG_SHARED) + blk_mq_sched_mark_restart_queue(hctx); + else + blk_mq_sched_mark_restart_hctx(hctx); if (!blk_mq_get_driver_tag(rq, &hctx, false)) break; }