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authorJens Axboe <axboe@suse.de>2005-10-20 16:42:29 +0200
committerJens Axboe <axboe@nelson.home.kernel.dk>2005-10-28 08:45:08 +0200
commitb4878f245ec8e168cdd1f170f823a750b7dd4af5 (patch)
treede784c2a7e1174e4843807998f0356bf92ee78be /drivers/block/deadline-iosched.c
parentd9ebb192aa13a026edc6faff137dcb14f2c91731 (diff)
downloadlwn-b4878f245ec8e168cdd1f170f823a750b7dd4af5.tar.gz
lwn-b4878f245ec8e168cdd1f170f823a750b7dd4af5.zip
[PATCH] 02/05: update ioscheds to use generic dispatch queue
This patch updates all four ioscheds to use generic dispatch queue. There's one behavior change in as-iosched. * In as-iosched, when force dispatching (ELEVATOR_INSERT_BACK), batch_data_dir is reset to REQ_SYNC and changed_batch and new_batch are cleared to zero. This prevernts AS from doing incorrect update_write_batch after the forced dispatched requests are finished. * In cfq-iosched, cfqd->rq_in_driver currently counts the number of activated (removed) requests to determine whether queue-kicking is needed and cfq_max_depth has been reached. With generic dispatch queue, I think counting the number of dispatched requests would be more appropriate. * cfq_max_depth can be lowered to 1 again. Original from Tejun Heo, modified version applied. Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'drivers/block/deadline-iosched.c')
-rw-r--r--drivers/block/deadline-iosched.c95
1 files changed, 17 insertions, 78 deletions
diff --git a/drivers/block/deadline-iosched.c b/drivers/block/deadline-iosched.c
index 52a3ae5289a0..07de4d24ddba 100644
--- a/drivers/block/deadline-iosched.c
+++ b/drivers/block/deadline-iosched.c
@@ -50,7 +50,6 @@ struct deadline_data {
* next in sort order. read, write or both are NULL
*/
struct deadline_rq *next_drq[2];
- struct list_head *dispatch; /* driver dispatch queue */
struct list_head *hash; /* request hash */
unsigned int batching; /* number of sequential requests made */
sector_t last_sector; /* head position */
@@ -239,10 +238,9 @@ deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
dd->next_drq[data_dir] = rb_entry_drq(rbnext);
}
- if (ON_RB(&drq->rb_node)) {
- rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
- RB_CLEAR(&drq->rb_node);
- }
+ BUG_ON(!ON_RB(&drq->rb_node));
+ rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
+ RB_CLEAR(&drq->rb_node);
}
static struct request *
@@ -286,7 +284,7 @@ deadline_find_first_drq(struct deadline_data *dd, int data_dir)
/*
* add drq to rbtree and fifo
*/
-static inline void
+static void
deadline_add_request(struct request_queue *q, struct request *rq)
{
struct deadline_data *dd = q->elevator->elevator_data;
@@ -315,14 +313,11 @@ deadline_add_request(struct request_queue *q, struct request *rq)
static void deadline_remove_request(request_queue_t *q, struct request *rq)
{
struct deadline_rq *drq = RQ_DATA(rq);
+ struct deadline_data *dd = q->elevator->elevator_data;
- if (drq) {
- struct deadline_data *dd = q->elevator->elevator_data;
-
- list_del_init(&drq->fifo);
- deadline_remove_merge_hints(q, drq);
- deadline_del_drq_rb(dd, drq);
- }
+ list_del_init(&drq->fifo);
+ deadline_remove_merge_hints(q, drq);
+ deadline_del_drq_rb(dd, drq);
}
static int
@@ -452,7 +447,7 @@ deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq)
request_queue_t *q = drq->request->q;
deadline_remove_request(q, drq->request);
- list_add_tail(&drq->request->queuelist, dd->dispatch);
+ elv_dispatch_add_tail(q, drq->request);
}
/*
@@ -502,8 +497,9 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
* deadline_dispatch_requests selects the best request according to
* read/write expire, fifo_batch, etc
*/
-static int deadline_dispatch_requests(struct deadline_data *dd)
+static int deadline_dispatch_requests(request_queue_t *q, int force)
{
+ struct deadline_data *dd = q->elevator->elevator_data;
const int reads = !list_empty(&dd->fifo_list[READ]);
const int writes = !list_empty(&dd->fifo_list[WRITE]);
struct deadline_rq *drq;
@@ -597,65 +593,12 @@ dispatch_request:
return 1;
}
-static struct request *deadline_next_request(request_queue_t *q)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
- struct request *rq;
-
- /*
- * if there are still requests on the dispatch queue, grab the first one
- */
- if (!list_empty(dd->dispatch)) {
-dispatch:
- rq = list_entry_rq(dd->dispatch->next);
- return rq;
- }
-
- if (deadline_dispatch_requests(dd))
- goto dispatch;
-
- return NULL;
-}
-
-static void
-deadline_insert_request(request_queue_t *q, struct request *rq, int where)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
-
- /* barriers must flush the reorder queue */
- if (unlikely(rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)
- && where == ELEVATOR_INSERT_SORT))
- where = ELEVATOR_INSERT_BACK;
-
- switch (where) {
- case ELEVATOR_INSERT_BACK:
- while (deadline_dispatch_requests(dd))
- ;
- list_add_tail(&rq->queuelist, dd->dispatch);
- break;
- case ELEVATOR_INSERT_FRONT:
- list_add(&rq->queuelist, dd->dispatch);
- break;
- case ELEVATOR_INSERT_SORT:
- BUG_ON(!blk_fs_request(rq));
- deadline_add_request(q, rq);
- break;
- default:
- printk("%s: bad insert point %d\n", __FUNCTION__,where);
- return;
- }
-}
-
static int deadline_queue_empty(request_queue_t *q)
{
struct deadline_data *dd = q->elevator->elevator_data;
- if (!list_empty(&dd->fifo_list[WRITE])
- || !list_empty(&dd->fifo_list[READ])
- || !list_empty(dd->dispatch))
- return 0;
-
- return 1;
+ return list_empty(&dd->fifo_list[WRITE])
+ && list_empty(&dd->fifo_list[READ]);
}
static struct request *
@@ -733,7 +676,6 @@ static int deadline_init_queue(request_queue_t *q, elevator_t *e)
INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
dd->sort_list[READ] = RB_ROOT;
dd->sort_list[WRITE] = RB_ROOT;
- dd->dispatch = &q->queue_head;
dd->fifo_expire[READ] = read_expire;
dd->fifo_expire[WRITE] = write_expire;
dd->writes_starved = writes_starved;
@@ -748,10 +690,8 @@ static void deadline_put_request(request_queue_t *q, struct request *rq)
struct deadline_data *dd = q->elevator->elevator_data;
struct deadline_rq *drq = RQ_DATA(rq);
- if (drq) {
- mempool_free(drq, dd->drq_pool);
- rq->elevator_private = NULL;
- }
+ mempool_free(drq, dd->drq_pool);
+ rq->elevator_private = NULL;
}
static int
@@ -917,9 +857,8 @@ static struct elevator_type iosched_deadline = {
.elevator_merge_fn = deadline_merge,
.elevator_merged_fn = deadline_merged_request,
.elevator_merge_req_fn = deadline_merged_requests,
- .elevator_next_req_fn = deadline_next_request,
- .elevator_add_req_fn = deadline_insert_request,
- .elevator_remove_req_fn = deadline_remove_request,
+ .elevator_dispatch_fn = deadline_dispatch_requests,
+ .elevator_add_req_fn = deadline_add_request,
.elevator_queue_empty_fn = deadline_queue_empty,
.elevator_former_req_fn = deadline_former_request,
.elevator_latter_req_fn = deadline_latter_request,