diff options
| author | Tatyana Brokhman <tlinder@codeaurora.org> | 2012-12-04 16:04:15 +0200 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2016-08-26 20:07:39 +0200 |
| commit | be8fae6f6fbf2ac2bfdf21b571333b3e98f7c5a9 (patch) | |
| tree | b09f8a26bb2223d9d990e75a39d5a9d5dd99d545 /include | |
| parent | 82356c71fd5b6b4ace46e4f31c318cc68657a598 (diff) | |
block: Add API for urgent request handling
This patch add support in block & elevator layers for handling
urgent requests. The decision if a request is urgent or not is taken
by the scheduler. Urgent request notification is passed to the underlying
block device driver (eMMC for example). Block device driver may decide to
interrupt the currently running low priority request to serve the new
urgent request. By doing so READ latency is greatly reduced in read&write
collision scenarios.
Note that if the current scheduler doesn't implement the urgent request
mechanism, this code path is never activated.
Change-Id: I8aa74b9b45c0d3a2221bd4e82ea76eb4103e7cfa
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: Stefan Guendhoer <stefan@guendhoer.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blkdev.h | 4 | ||||
| -rw-r--r-- | include/linux/elevator.h | 2 |
2 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index b3694b9d6..2e9fc2b42 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -387,6 +387,7 @@ struct request_queue { struct request_list root_rl; request_fn_proc *request_fn; + request_fn_proc *urgent_request_fn; make_request_fn *make_request_fn; prep_rq_fn *prep_rq_fn; unprep_rq_fn *unprep_rq_fn; @@ -487,6 +488,8 @@ struct request_queue { #endif struct queue_limits limits; + bool notified_urgent; + bool dispatched_urgent; /* * sg stuff @@ -993,6 +996,7 @@ extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn, extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *); extern struct request_queue *blk_init_allocated_queue(struct request_queue *, request_fn_proc *, spinlock_t *); +extern void blk_urgent_request(struct request_queue *q, request_fn_proc *fn); extern void blk_cleanup_queue(struct request_queue *); extern void blk_queue_make_request(struct request_queue *, make_request_fn *); extern void blk_queue_bounce_limit(struct request_queue *, u64); diff --git a/include/linux/elevator.h b/include/linux/elevator.h index d458ea48d..b3afa35d5 100644 --- a/include/linux/elevator.h +++ b/include/linux/elevator.h @@ -26,6 +26,7 @@ typedef int (elevator_dispatch_fn) (struct request_queue *, int); typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); typedef int (elevator_reinsert_req_fn) (struct request_queue *, struct request *); +typedef bool (elevator_is_urgent_fn) (struct request_queue *); typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *); typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *); typedef int (elevator_may_queue_fn) (struct request_queue *, int); @@ -53,6 +54,7 @@ struct elevator_ops elevator_dispatch_fn *elevator_dispatch_fn; elevator_add_req_fn *elevator_add_req_fn; elevator_reinsert_req_fn *elevator_reinsert_req_fn; + elevator_is_urgent_fn *elevator_is_urgent_fn; elevator_activate_req_fn *elevator_activate_req_fn; elevator_deactivate_req_fn *elevator_deactivate_req_fn; |