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authorJens Axboe <axboe@fb.com>2017-01-17 06:03:22 -0700
committerJens Axboe <axboe@fb.com>2017-01-17 10:04:20 -0700
commitbd166ef183c263c5ced656d49ef19c7da4adc774 (patch)
tree449bbd3b4e671b370b96e3846b2281116e7089e9 /block/blk-mq-sched.h
parent2af8cbe30531eca73c8f3ba277f155fc0020b01a (diff)
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blk-mq-sched: add framework for MQ capable IO schedulers
This adds a set of hooks that intercepts the blk-mq path of allocating/inserting/issuing/completing requests, allowing us to develop a scheduler within that framework. We reuse the existing elevator scheduler API on the registration side, but augment that with the scheduler flagging support for the blk-mq interfce, and with a separate set of ops hooks for MQ devices. We split driver and scheduler tags, so we can run the scheduling independently of device queue depth. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com>
Diffstat (limited to 'block/blk-mq-sched.h')
-rw-r--r--block/blk-mq-sched.h170
1 files changed, 170 insertions, 0 deletions
diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
new file mode 100644
index 000000000000..35c49e2e008a
--- /dev/null
+++ b/block/blk-mq-sched.h
@@ -0,0 +1,170 @@
+#ifndef BLK_MQ_SCHED_H
+#define BLK_MQ_SCHED_H
+
+#include "blk-mq.h"
+#include "blk-mq-tag.h"
+
+int blk_mq_sched_init_hctx_data(struct request_queue *q, size_t size,
+ int (*init)(struct blk_mq_hw_ctx *),
+ void (*exit)(struct blk_mq_hw_ctx *));
+
+void blk_mq_sched_free_hctx_data(struct request_queue *q,
+ void (*exit)(struct blk_mq_hw_ctx *));
+
+struct request *blk_mq_sched_get_request(struct request_queue *q, struct bio *bio, unsigned int op, struct blk_mq_alloc_data *data);
+void blk_mq_sched_put_request(struct request *rq);
+
+void blk_mq_sched_request_inserted(struct request *rq);
+bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx, struct request *rq);
+bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio);
+bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio);
+bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq);
+
+void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx);
+void blk_mq_sched_move_to_dispatch(struct blk_mq_hw_ctx *hctx,
+ struct list_head *rq_list,
+ struct request *(*get_rq)(struct blk_mq_hw_ctx *));
+
+int blk_mq_sched_setup(struct request_queue *q);
+void blk_mq_sched_teardown(struct request_queue *q);
+
+static inline bool
+blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio)
+{
+ struct elevator_queue *e = q->elevator;
+
+ if (!e || blk_queue_nomerges(q) || !bio_mergeable(bio))
+ return false;
+
+ return __blk_mq_sched_bio_merge(q, bio);
+}
+
+static inline int blk_mq_sched_get_rq_priv(struct request_queue *q,
+ struct request *rq)
+{
+ struct elevator_queue *e = q->elevator;
+
+ if (e && e->type->ops.mq.get_rq_priv)
+ return e->type->ops.mq.get_rq_priv(q, rq);
+
+ return 0;
+}
+
+static inline void blk_mq_sched_put_rq_priv(struct request_queue *q,
+ struct request *rq)
+{
+ struct elevator_queue *e = q->elevator;
+
+ if (e && e->type->ops.mq.put_rq_priv)
+ e->type->ops.mq.put_rq_priv(q, rq);
+}
+
+static inline void
+blk_mq_sched_insert_request(struct request *rq, bool at_head, bool run_queue,
+ bool async)
+{
+ struct request_queue *q = rq->q;
+ struct elevator_queue *e = q->elevator;
+ struct blk_mq_ctx *ctx = rq->mq_ctx;
+ struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
+
+ if (e && e->type->ops.mq.insert_requests) {
+ LIST_HEAD(list);
+
+ list_add(&rq->queuelist, &list);
+ e->type->ops.mq.insert_requests(hctx, &list, at_head);
+ } else {
+ spin_lock(&ctx->lock);
+ __blk_mq_insert_request(hctx, rq, at_head);
+ spin_unlock(&ctx->lock);
+ }
+
+ if (run_queue)
+ blk_mq_run_hw_queue(hctx, async);
+}
+
+static inline void
+blk_mq_sched_insert_requests(struct request_queue *q, struct blk_mq_ctx *ctx,
+ struct list_head *list, bool run_queue_async)
+{
+ struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
+ struct elevator_queue *e = hctx->queue->elevator;
+
+ if (e && e->type->ops.mq.insert_requests)
+ e->type->ops.mq.insert_requests(hctx, list, false);
+ else
+ blk_mq_insert_requests(hctx, ctx, list);
+
+ blk_mq_run_hw_queue(hctx, run_queue_async);
+}
+
+static inline bool
+blk_mq_sched_allow_merge(struct request_queue *q, struct request *rq,
+ struct bio *bio)
+{
+ struct elevator_queue *e = q->elevator;
+
+ if (e && e->type->ops.mq.allow_merge)
+ return e->type->ops.mq.allow_merge(q, rq, bio);
+
+ return true;
+}
+
+static inline void
+blk_mq_sched_completed_request(struct blk_mq_hw_ctx *hctx, struct request *rq)
+{
+ struct elevator_queue *e = hctx->queue->elevator;
+
+ if (e && e->type->ops.mq.completed_request)
+ e->type->ops.mq.completed_request(hctx, rq);
+
+ BUG_ON(rq->internal_tag == -1);
+
+ blk_mq_put_tag(hctx, hctx->sched_tags, rq->mq_ctx, rq->internal_tag);
+
+ if (test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) {
+ clear_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
+ blk_mq_run_hw_queue(hctx, true);
+ }
+}
+
+static inline void blk_mq_sched_started_request(struct request *rq)
+{
+ struct request_queue *q = rq->q;
+ struct elevator_queue *e = q->elevator;
+
+ if (e && e->type->ops.mq.started_request)
+ e->type->ops.mq.started_request(rq);
+}
+
+static inline void blk_mq_sched_requeue_request(struct request *rq)
+{
+ struct request_queue *q = rq->q;
+ struct elevator_queue *e = q->elevator;
+
+ if (e && e->type->ops.mq.requeue_request)
+ e->type->ops.mq.requeue_request(rq);
+}
+
+static inline bool blk_mq_sched_has_work(struct blk_mq_hw_ctx *hctx)
+{
+ struct elevator_queue *e = hctx->queue->elevator;
+
+ if (e && e->type->ops.mq.has_work)
+ return e->type->ops.mq.has_work(hctx);
+
+ return false;
+}
+
+static inline void blk_mq_sched_mark_restart(struct blk_mq_hw_ctx *hctx)
+{
+ if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state))
+ set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
+}
+
+static inline bool blk_mq_sched_needs_restart(struct blk_mq_hw_ctx *hctx)
+{
+ return test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
+}
+
+#endif