[PATCH] 01/05 Implement generic dispatch queue
Implements generic dispatch queue which can replace all
dispatch queues implemented by each iosched. This reduces
code duplication, eases enforcing semantics over dispatch
queue, and simplifies specific ioscheds.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index efdc9b5..2c7b915 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -203,6 +203,7 @@
enum rq_flag_bits {
__REQ_RW, /* not set, read. set, write */
__REQ_FAILFAST, /* no low level driver retries */
+ __REQ_SORTED, /* elevator knows about this request */
__REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
__REQ_HARDBARRIER, /* may not be passed by drive either */
__REQ_CMD, /* is a regular fs rw request */
@@ -235,6 +236,7 @@
#define REQ_RW (1 << __REQ_RW)
#define REQ_FAILFAST (1 << __REQ_FAILFAST)
+#define REQ_SORTED (1 << __REQ_SORTED)
#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
#define REQ_CMD (1 << __REQ_CMD)
@@ -333,6 +335,13 @@
end_flush_fn *end_flush_fn;
/*
+ * Dispatch queue sorting
+ */
+ sector_t last_sector;
+ struct request *boundary_rq;
+ unsigned int max_back_kb;
+
+ /*
* Auto-unplugging state
*/
struct timer_list unplug_timer;
@@ -454,6 +463,7 @@
#define blk_pm_request(rq) \
((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
+#define blk_sorted_rq(rq) ((rq)->flags & REQ_SORTED)
#define blk_barrier_rq(rq) ((rq)->flags & REQ_HARDBARRIER)
#define blk_barrier_preflush(rq) ((rq)->flags & REQ_BAR_PREFLUSH)
#define blk_barrier_postflush(rq) ((rq)->flags & REQ_BAR_POSTFLUSH)
@@ -611,12 +621,7 @@
static inline void blkdev_dequeue_request(struct request *req)
{
- BUG_ON(list_empty(&req->queuelist));
-
- list_del_init(&req->queuelist);
-
- if (req->rl)
- elv_remove_request(req->q, req);
+ elv_dequeue_request(req->q, req);
}
/*
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index ea6bbc2..76f4f69 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -8,18 +8,17 @@
typedef void (elevator_merged_fn) (request_queue_t *, struct request *);
-typedef struct request *(elevator_next_req_fn) (request_queue_t *);
+typedef int (elevator_dispatch_fn) (request_queue_t *, int);
-typedef void (elevator_add_req_fn) (request_queue_t *, struct request *, int);
+typedef void (elevator_add_req_fn) (request_queue_t *, struct request *);
typedef int (elevator_queue_empty_fn) (request_queue_t *);
-typedef void (elevator_remove_req_fn) (request_queue_t *, struct request *);
-typedef void (elevator_requeue_req_fn) (request_queue_t *, struct request *);
typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *);
typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *);
typedef int (elevator_may_queue_fn) (request_queue_t *, int, struct bio *);
typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, int);
typedef void (elevator_put_req_fn) (request_queue_t *, struct request *);
+typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *);
typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *);
typedef int (elevator_init_fn) (request_queue_t *, elevator_t *);
@@ -31,10 +30,9 @@
elevator_merged_fn *elevator_merged_fn;
elevator_merge_req_fn *elevator_merge_req_fn;
- elevator_next_req_fn *elevator_next_req_fn;
+ elevator_dispatch_fn *elevator_dispatch_fn;
elevator_add_req_fn *elevator_add_req_fn;
- elevator_remove_req_fn *elevator_remove_req_fn;
- elevator_requeue_req_fn *elevator_requeue_req_fn;
+ elevator_activate_req_fn *elevator_activate_req_fn;
elevator_deactivate_req_fn *elevator_deactivate_req_fn;
elevator_queue_empty_fn *elevator_queue_empty_fn;
@@ -81,15 +79,15 @@
/*
* block elevator interface
*/
+extern void elv_dispatch_insert(request_queue_t *, struct request *, int);
extern void elv_add_request(request_queue_t *, struct request *, int, int);
extern void __elv_add_request(request_queue_t *, struct request *, int, int);
extern int elv_merge(request_queue_t *, struct request **, struct bio *);
extern void elv_merge_requests(request_queue_t *, struct request *,
struct request *);
extern void elv_merged_request(request_queue_t *, struct request *);
-extern void elv_remove_request(request_queue_t *, struct request *);
+extern void elv_dequeue_request(request_queue_t *, struct request *);
extern void elv_requeue_request(request_queue_t *, struct request *);
-extern void elv_deactivate_request(request_queue_t *, struct request *);
extern int elv_queue_empty(request_queue_t *);
extern struct request *elv_next_request(struct request_queue *q);
extern struct request *elv_former_request(request_queue_t *, struct request *);