02_blk_generic-dispatch-queue-update-for-ioscheds.patch
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.
Signed-off-by: Tejun Heo <[email protected]>
as-iosched.c | 294 +++++++++++++--------------------------------
cfq-iosched.c | 344 ++++++++++++-----------------------------------------
deadline-iosched.c | 95 ++------------
noop-iosched.c | 17 --
4 files changed, 191 insertions(+), 559 deletions(-)
Index: blk-fixes/drivers/block/as-iosched.c
===================================================================
--- blk-fixes.orig/drivers/block/as-iosched.c 2005-10-19 21:26:16.000000000 +0900
+++ blk-fixes/drivers/block/as-iosched.c 2005-10-19 21:34:02.000000000 +0900
@@ -98,7 +98,6 @@ struct as_data {
struct as_rq *next_arq[2]; /* next in sort order */
sector_t last_sector[2]; /* last REQ_SYNC & REQ_ASYNC sectors */
- struct list_head *dispatch; /* driver dispatch queue */
struct list_head *hash; /* request hash */
unsigned long exit_prob; /* probability a task will exit while
@@ -239,6 +238,25 @@ static struct io_context *as_get_io_cont
return ioc;
}
+static void as_put_io_context(struct as_rq *arq)
+{
+ struct as_io_context *aic;
+
+ if (unlikely(!arq->io_context))
+ return;
+
+ aic = arq->io_context->aic;
+
+ if (arq->is_sync == REQ_SYNC && aic) {
+ spin_lock(&aic->lock);
+ set_bit(AS_TASK_IORUNNING, &aic->state);
+ aic->last_end_request = jiffies;
+ spin_unlock(&aic->lock);
+ }
+
+ put_io_context(arq->io_context);
+}
+
/*
* the back merge hash support functions
*/
@@ -950,23 +968,12 @@ static void as_completed_request(request
WARN_ON(!list_empty(&rq->queuelist));
- if (arq->state == AS_RQ_PRESCHED) {
- WARN_ON(arq->io_context);
- goto out;
- }
-
- if (arq->state == AS_RQ_MERGED)
- goto out_ioc;
-
if (arq->state != AS_RQ_REMOVED) {
printk("arq->state %d\n", arq->state);
WARN_ON(1);
goto out;
}
- if (!blk_fs_request(rq))
- goto out;
-
if (ad->changed_batch && ad->nr_dispatched == 1) {
kblockd_schedule_work(&ad->antic_work);
ad->changed_batch = 0;
@@ -1001,21 +1008,7 @@ static void as_completed_request(request
}
}
-out_ioc:
- if (!arq->io_context)
- goto out;
-
- if (arq->is_sync == REQ_SYNC) {
- struct as_io_context *aic = arq->io_context->aic;
- if (aic) {
- spin_lock(&aic->lock);
- set_bit(AS_TASK_IORUNNING, &aic->state);
- aic->last_end_request = jiffies;
- spin_unlock(&aic->lock);
- }
- }
-
- put_io_context(arq->io_context);
+ as_put_io_context(arq);
out:
arq->state = AS_RQ_POSTSCHED;
}
@@ -1052,68 +1045,6 @@ static void as_remove_queued_request(req
}
/*
- * as_remove_dispatched_request is called to remove a request which has gone
- * to the dispatch list.
- */
-static void as_remove_dispatched_request(request_queue_t *q, struct request *rq)
-{
- struct as_rq *arq = RQ_DATA(rq);
- struct as_io_context *aic;
-
- if (!arq) {
- WARN_ON(1);
- return;
- }
-
- WARN_ON(arq->state != AS_RQ_DISPATCHED);
- WARN_ON(ON_RB(&arq->rb_node));
- if (arq->io_context && arq->io_context->aic) {
- aic = arq->io_context->aic;
- if (aic) {
- WARN_ON(!atomic_read(&aic->nr_dispatched));
- atomic_dec(&aic->nr_dispatched);
- }
- }
-}
-
-/*
- * as_remove_request is called when a driver has finished with a request.
- * This should be only called for dispatched requests, but for some reason
- * a POWER4 box running hwscan it does not.
- */
-static void as_remove_request(request_queue_t *q, struct request *rq)
-{
- struct as_rq *arq = RQ_DATA(rq);
-
- if (unlikely(arq->state == AS_RQ_NEW))
- goto out;
-
- if (ON_RB(&arq->rb_node)) {
- if (arq->state != AS_RQ_QUEUED) {
- printk("arq->state %d\n", arq->state);
- WARN_ON(1);
- goto out;
- }
- /*
- * We'll lose the aliased request(s) here. I don't think this
- * will ever happen, but if it does, hopefully someone will
- * report it.
- */
- WARN_ON(!list_empty(&rq->queuelist));
- as_remove_queued_request(q, rq);
- } else {
- if (arq->state != AS_RQ_DISPATCHED) {
- printk("arq->state %d\n", arq->state);
- WARN_ON(1);
- goto out;
- }
- as_remove_dispatched_request(q, rq);
- }
-out:
- arq->state = AS_RQ_REMOVED;
-}
-
-/*
* as_fifo_expired returns 0 if there are no expired reads on the fifo,
* 1 otherwise. It is ratelimited so that we only perform the check once per
* `fifo_expire' interval. Otherwise a large number of expired requests
@@ -1162,10 +1093,9 @@ static inline int as_batch_expired(struc
/*
* move an entry to dispatch queue
*/
-static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
+static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq, int force)
{
struct request *rq = arq->request;
- struct list_head *insert;
const int data_dir = arq->is_sync;
BUG_ON(!ON_RB(&arq->rb_node));
@@ -1198,13 +1128,13 @@ static void as_move_to_dispatch(struct a
/*
* take it off the sort and fifo list, add to dispatch queue
*/
- insert = ad->dispatch->prev;
-
while (!list_empty(&rq->queuelist)) {
struct request *__rq = list_entry_rq(rq->queuelist.next);
struct as_rq *__arq = RQ_DATA(__rq);
- list_move_tail(&__rq->queuelist, ad->dispatch);
+ list_del(&__rq->queuelist);
+
+ elv_dispatch_insert(ad->q, __rq, force);
if (__arq->io_context && __arq->io_context->aic)
atomic_inc(&__arq->io_context->aic->nr_dispatched);
@@ -1218,7 +1148,8 @@ static void as_move_to_dispatch(struct a
as_remove_queued_request(ad->q, rq);
WARN_ON(arq->state != AS_RQ_QUEUED);
- list_add(&rq->queuelist, insert);
+ elv_dispatch_insert(ad->q, rq, force);
+
arq->state = AS_RQ_DISPATCHED;
if (arq->io_context && arq->io_context->aic)
atomic_inc(&arq->io_context->aic->nr_dispatched);
@@ -1230,12 +1161,42 @@ static void as_move_to_dispatch(struct a
* read/write expire, batch expire, etc, and moves it to the dispatch
* queue. Returns 1 if a request was found, 0 otherwise.
*/
-static int as_dispatch_request(struct as_data *ad)
+static int as_dispatch_request(request_queue_t *q, int force)
{
+ struct as_data *ad = q->elevator->elevator_data;
struct as_rq *arq;
const int reads = !list_empty(&ad->fifo_list[REQ_SYNC]);
const int writes = !list_empty(&ad->fifo_list[REQ_ASYNC]);
+ if (unlikely(force)) {
+ /*
+ * Forced dispatch, accounting is useless. Reset
+ * accounting states and dump fifo_lists. Note that
+ * batch_data_dir is reset to REQ_SYNC to avoid
+ * screwing write batch accounting as write batch
+ * accounting occurs on W->R transition.
+ */
+ int dispatched = 0;
+
+ ad->batch_data_dir = REQ_SYNC;
+ ad->changed_batch = 0;
+ ad->new_batch = 0;
+
+ while (ad->next_arq[REQ_SYNC]) {
+ as_move_to_dispatch(ad, ad->next_arq[REQ_SYNC], 1);
+ dispatched++;
+ }
+ ad->last_check_fifo[REQ_SYNC] = jiffies;
+
+ while (ad->next_arq[REQ_ASYNC]) {
+ as_move_to_dispatch(ad, ad->next_arq[REQ_ASYNC], 1);
+ dispatched++;
+ }
+ ad->last_check_fifo[REQ_ASYNC] = jiffies;
+
+ return dispatched;
+ }
+
/* Signal that the write batch was uncontended, so we can't time it */
if (ad->batch_data_dir == REQ_ASYNC && !reads) {
if (ad->current_write_count == 0 || !writes)
@@ -1354,25 +1315,11 @@ fifo_expired:
/*
* arq is the selected appropriate request.
*/
- as_move_to_dispatch(ad, arq);
+ as_move_to_dispatch(ad, arq, 0);
return 1;
}
-static struct request *as_next_request(request_queue_t *q)
-{
- struct as_data *ad = q->elevator->elevator_data;
- struct request *rq = NULL;
-
- /*
- * if there are still requests on the dispatch queue, grab the first
- */
- if (!list_empty(ad->dispatch) || as_dispatch_request(ad))
- rq = list_entry_rq(ad->dispatch->next);
-
- return rq;
-}
-
/*
* Add arq to a list behind alias
*/
@@ -1410,11 +1357,19 @@ as_add_aliased_request(struct as_data *a
/*
* add arq to rbtree and fifo
*/
-static void as_add_request(struct as_data *ad, struct as_rq *arq)
+static void as_add_request(request_queue_t *q, struct request *rq)
{
+ struct as_data *ad = q->elevator->elevator_data;
+ struct as_rq *arq = RQ_DATA(rq);
struct as_rq *alias;
int data_dir;
+ if (arq->state != AS_RQ_PRESCHED) {
+ printk("arq->state: %d\n", arq->state);
+ WARN_ON(1);
+ }
+ arq->state = AS_RQ_NEW;
+
if (rq_data_dir(arq->request) == READ
|| current->flags&PF_SYNCWRITE)
arq->is_sync = 1;
@@ -1463,96 +1418,24 @@ static void as_add_request(struct as_dat
arq->state = AS_RQ_QUEUED;
}
-static void as_deactivate_request(request_queue_t *q, struct request *rq)
+static void as_activate_request(request_queue_t *q, struct request *rq)
{
- struct as_data *ad = q->elevator->elevator_data;
struct as_rq *arq = RQ_DATA(rq);
- if (arq) {
- if (arq->state == AS_RQ_REMOVED) {
- arq->state = AS_RQ_DISPATCHED;
- if (arq->io_context && arq->io_context->aic)
- atomic_inc(&arq->io_context->aic->nr_dispatched);
- }
- } else
- WARN_ON(blk_fs_request(rq)
- && (!(rq->flags & (REQ_HARDBARRIER|REQ_SOFTBARRIER))) );
-
- /* Stop anticipating - let this request get through */
- as_antic_stop(ad);
-}
-
-/*
- * requeue the request. The request has not been completed, nor is it a
- * new request, so don't touch accounting.
- */
-static void as_requeue_request(request_queue_t *q, struct request *rq)
-{
- as_deactivate_request(q, rq);
- list_add(&rq->queuelist, &q->queue_head);
-}
-
-/*
- * Account a request that is inserted directly onto the dispatch queue.
- * arq->io_context->aic->nr_dispatched should not need to be incremented
- * because only new requests should come through here: requeues go through
- * our explicit requeue handler.
- */
-static void as_account_queued_request(struct as_data *ad, struct request *rq)
-{
- if (blk_fs_request(rq)) {
- struct as_rq *arq = RQ_DATA(rq);
- arq->state = AS_RQ_DISPATCHED;
- ad->nr_dispatched++;
- }
+ WARN_ON(arq->state != AS_RQ_DISPATCHED);
+ arq->state = AS_RQ_REMOVED;
+ if (arq->io_context && arq->io_context->aic)
+ atomic_dec(&arq->io_context->aic->nr_dispatched);
}
-static void
-as_insert_request(request_queue_t *q, struct request *rq, int where)
+static void as_deactivate_request(request_queue_t *q, struct request *rq)
{
- struct as_data *ad = q->elevator->elevator_data;
struct as_rq *arq = RQ_DATA(rq);
- if (arq) {
- if (arq->state != AS_RQ_PRESCHED) {
- printk("arq->state: %d\n", arq->state);
- WARN_ON(1);
- }
- arq->state = AS_RQ_NEW;
- }
-
- /* barriers must flush the reorder queue */
- if (unlikely(rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)
- && where == ELEVATOR_INSERT_SORT)) {
- WARN_ON(1);
- where = ELEVATOR_INSERT_BACK;
- }
-
- switch (where) {
- case ELEVATOR_INSERT_BACK:
- while (ad->next_arq[REQ_SYNC])
- as_move_to_dispatch(ad, ad->next_arq[REQ_SYNC]);
-
- while (ad->next_arq[REQ_ASYNC])
- as_move_to_dispatch(ad, ad->next_arq[REQ_ASYNC]);
-
- list_add_tail(&rq->queuelist, ad->dispatch);
- as_account_queued_request(ad, rq);
- as_antic_stop(ad);
- break;
- case ELEVATOR_INSERT_FRONT:
- list_add(&rq->queuelist, ad->dispatch);
- as_account_queued_request(ad, rq);
- as_antic_stop(ad);
- break;
- case ELEVATOR_INSERT_SORT:
- BUG_ON(!blk_fs_request(rq));
- as_add_request(ad, arq);
- break;
- default:
- BUG();
- return;
- }
+ WARN_ON(arq->state != AS_RQ_REMOVED);
+ arq->state = AS_RQ_DISPATCHED;
+ if (arq->io_context && arq->io_context->aic)
+ atomic_inc(&arq->io_context->aic->nr_dispatched);
}
/*
@@ -1565,12 +1448,8 @@ static int as_queue_empty(request_queue_
{
struct as_data *ad = q->elevator->elevator_data;
- if (!list_empty(&ad->fifo_list[REQ_ASYNC])
- || !list_empty(&ad->fifo_list[REQ_SYNC])
- || !list_empty(ad->dispatch))
- return 0;
-
- return 1;
+ return list_empty(&ad->fifo_list[REQ_ASYNC])
+ && list_empty(&ad->fifo_list[REQ_SYNC]);
}
static struct request *
@@ -1763,6 +1642,7 @@ as_merged_requests(request_queue_t *q, s
* kill knowledge of next, this one is a goner
*/
as_remove_queued_request(q, next);
+ as_put_io_context(anext);
anext->state = AS_RQ_MERGED;
}
@@ -1782,7 +1662,7 @@ static void as_work_handler(void *data)
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
- if (as_next_request(q))
+ if (!as_queue_empty(q))
q->request_fn(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
@@ -1797,7 +1677,9 @@ static void as_put_request(request_queue
return;
}
- if (arq->state != AS_RQ_POSTSCHED && arq->state != AS_RQ_PRESCHED) {
+ if (unlikely(arq->state != AS_RQ_POSTSCHED &&
+ arq->state != AS_RQ_PRESCHED &&
+ arq->state != AS_RQ_MERGED)) {
printk("arq->state %d\n", arq->state);
WARN_ON(1);
}
@@ -1907,7 +1789,6 @@ static int as_init_queue(request_queue_t
INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]);
ad->sort_list[REQ_SYNC] = RB_ROOT;
ad->sort_list[REQ_ASYNC] = RB_ROOT;
- ad->dispatch = &q->queue_head;
ad->fifo_expire[REQ_SYNC] = default_read_expire;
ad->fifo_expire[REQ_ASYNC] = default_write_expire;
ad->antic_expire = default_antic_expire;
@@ -2072,10 +1953,9 @@ static struct elevator_type iosched_as =
.elevator_merge_fn = as_merge,
.elevator_merged_fn = as_merged_request,
.elevator_merge_req_fn = as_merged_requests,
- .elevator_next_req_fn = as_next_request,
- .elevator_add_req_fn = as_insert_request,
- .elevator_remove_req_fn = as_remove_request,
- .elevator_requeue_req_fn = as_requeue_request,
+ .elevator_dispatch_fn = as_dispatch_request,
+ .elevator_add_req_fn = as_add_request,
+ .elevator_activate_req_fn = as_activate_request,
.elevator_deactivate_req_fn = as_deactivate_request,
.elevator_queue_empty_fn = as_queue_empty,
.elevator_completed_req_fn = as_completed_request,
Index: blk-fixes/drivers/block/deadline-iosched.c
===================================================================
--- blk-fixes.orig/drivers/block/deadline-iosched.c 2005-10-19 21:26:16.000000000 +0900
+++ blk-fixes/drivers/block/deadline-iosched.c 2005-10-19 21:34:02.000000000 +0900
@@ -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->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_
/*
* 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_queu
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 deadlin
request_queue_t *q = drq->request->q;
deadline_remove_request(q, drq->request);
- list_add_tail(&drq->request->queuelist, dd->dispatch);
+ elv_dispatch_insert(q, drq->request, 0);
}
/*
@@ -502,8 +497,9 @@ static inline int deadline_check_fifo(st
* 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_q
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
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_dead
.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,
Index: blk-fixes/drivers/block/noop-iosched.c
===================================================================
--- blk-fixes.orig/drivers/block/noop-iosched.c 2005-10-19 21:26:16.000000000 +0900
+++ blk-fixes/drivers/block/noop-iosched.c 2005-10-19 21:34:02.000000000 +0900
@@ -28,13 +28,9 @@ static void elevator_noop_merge_requests
list_del_init(&next->queuelist);
}
-static void elevator_noop_add_request(request_queue_t *q, struct request *rq,
- int where)
+static void elevator_noop_add_request(request_queue_t *q, struct request *rq)
{
- if (where == ELEVATOR_INSERT_FRONT)
- list_add(&rq->queuelist, &q->queue_head);
- else
- list_add_tail(&rq->queuelist, &q->queue_head);
+ elv_dispatch_insert(q, rq, 0);
/*
* new merges must not precede this barrier
@@ -45,19 +41,16 @@ static void elevator_noop_add_request(re
q->last_merge = rq;
}
-static struct request *elevator_noop_next_request(request_queue_t *q)
+static int elevator_noop_dispatch(request_queue_t *q, int force)
{
- if (!list_empty(&q->queue_head))
- return list_entry_rq(q->queue_head.next);
-
- return NULL;
+ return 0;
}
static struct elevator_type elevator_noop = {
.ops = {
.elevator_merge_fn = elevator_noop_merge,
.elevator_merge_req_fn = elevator_noop_merge_requests,
- .elevator_next_req_fn = elevator_noop_next_request,
+ .elevator_dispatch_fn = elevator_noop_dispatch,
.elevator_add_req_fn = elevator_noop_add_request,
},
.elevator_name = "noop",
Index: blk-fixes/drivers/block/cfq-iosched.c
===================================================================
--- blk-fixes.orig/drivers/block/cfq-iosched.c 2005-10-19 21:26:16.000000000 +0900
+++ blk-fixes/drivers/block/cfq-iosched.c 2005-10-19 21:34:02.000000000 +0900
@@ -84,7 +84,6 @@ static int cfq_max_depth = 2;
(node)->rb_left = NULL; \
} while (0)
#define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL)
-#define ON_RB(node) ((node)->rb_color != RB_NONE)
#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node)
#define rq_rb_key(rq) (rq)->sector
@@ -271,10 +270,7 @@ CFQ_CFQQ_FNS(expired);
#undef CFQ_CFQQ_FNS
enum cfq_rq_state_flags {
- CFQ_CRQ_FLAG_in_flight = 0,
- CFQ_CRQ_FLAG_in_driver,
- CFQ_CRQ_FLAG_is_sync,
- CFQ_CRQ_FLAG_requeued,
+ CFQ_CRQ_FLAG_is_sync = 0,
};
#define CFQ_CRQ_FNS(name) \
@@ -291,14 +287,11 @@ static inline int cfq_crq_##name(const s
return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \
}
-CFQ_CRQ_FNS(in_flight);
-CFQ_CRQ_FNS(in_driver);
CFQ_CRQ_FNS(is_sync);
-CFQ_CRQ_FNS(requeued);
#undef CFQ_CRQ_FNS
static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
-static void cfq_dispatch_sort(request_queue_t *, struct cfq_rq *);
+static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *, int);
static void cfq_put_cfqd(struct cfq_data *cfqd);
#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE)
@@ -347,18 +340,13 @@ static struct request *cfq_find_rq_hash(
return NULL;
}
-static inline int cfq_pending_requests(struct cfq_data *cfqd)
-{
- return !list_empty(&cfqd->queue->queue_head) || cfqd->busy_queues;
-}
-
/*
* scheduler run of queue, if there are requests pending and no one in the
* driver that will restart queueing
*/
static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
{
- if (!cfqd->rq_in_driver && cfq_pending_requests(cfqd))
+ if (!cfqd->rq_in_driver && cfqd->busy_queues)
kblockd_schedule_work(&cfqd->unplug_work);
}
@@ -366,7 +354,7 @@ static int cfq_queue_empty(request_queue
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- return !cfq_pending_requests(cfqd);
+ return !cfqd->busy_queues;
}
/*
@@ -386,11 +374,6 @@ cfq_choose_req(struct cfq_data *cfqd, st
if (crq2 == NULL)
return crq1;
- if (cfq_crq_requeued(crq1) && !cfq_crq_requeued(crq2))
- return crq1;
- else if (cfq_crq_requeued(crq2) && !cfq_crq_requeued(crq1))
- return crq2;
-
if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2))
return crq1;
else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1))
@@ -461,10 +444,7 @@ cfq_find_next_crq(struct cfq_data *cfqd,
struct cfq_rq *crq_next = NULL, *crq_prev = NULL;
struct rb_node *rbnext, *rbprev;
- rbnext = NULL;
- if (ON_RB(&last->rb_node))
- rbnext = rb_next(&last->rb_node);
- if (!rbnext) {
+ if (!(rbnext = rb_next(&last->rb_node))) {
rbnext = rb_first(&cfqq->sort_list);
if (rbnext == &last->rb_node)
rbnext = NULL;
@@ -545,13 +525,13 @@ static void cfq_resort_rr_list(struct cf
* the pending list according to last request service
*/
static inline void
-cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq, int requeue)
+cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
BUG_ON(cfq_cfqq_on_rr(cfqq));
cfq_mark_cfqq_on_rr(cfqq);
cfqd->busy_queues++;
- cfq_resort_rr_list(cfqq, requeue);
+ cfq_resort_rr_list(cfqq, 0);
}
static inline void
@@ -571,22 +551,19 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, s
static inline void cfq_del_crq_rb(struct cfq_rq *crq)
{
struct cfq_queue *cfqq = crq->cfq_queue;
+ struct cfq_data *cfqd = cfqq->cfqd;
+ const int sync = cfq_crq_is_sync(crq);
- if (ON_RB(&crq->rb_node)) {
- struct cfq_data *cfqd = cfqq->cfqd;
- const int sync = cfq_crq_is_sync(crq);
-
- BUG_ON(!cfqq->queued[sync]);
- cfqq->queued[sync]--;
+ BUG_ON(!cfqq->queued[sync]);
+ cfqq->queued[sync]--;
- cfq_update_next_crq(crq);
+ cfq_update_next_crq(crq);
- rb_erase(&crq->rb_node, &cfqq->sort_list);
- RB_CLEAR_COLOR(&crq->rb_node);
+ rb_erase(&crq->rb_node, &cfqq->sort_list);
+ RB_CLEAR_COLOR(&crq->rb_node);
- if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
- cfq_del_cfqq_rr(cfqd, cfqq);
- }
+ if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
+ cfq_del_cfqq_rr(cfqd, cfqq);
}
static struct cfq_rq *
@@ -627,12 +604,12 @@ static void cfq_add_crq_rb(struct cfq_rq
* if that happens, put the alias on the dispatch list
*/
while ((__alias = __cfq_add_crq_rb(crq)) != NULL)
- cfq_dispatch_sort(cfqd->queue, __alias);
+ cfq_dispatch_insert(cfqd->queue, __alias, 1);
rb_insert_color(&crq->rb_node, &cfqq->sort_list);
if (!cfq_cfqq_on_rr(cfqq))
- cfq_add_cfqq_rr(cfqd, cfqq, cfq_crq_requeued(crq));
+ cfq_add_cfqq_rr(cfqd, cfqq);
/*
* check if this request is a better next-serve candidate
@@ -643,10 +620,8 @@ static void cfq_add_crq_rb(struct cfq_rq
static inline void
cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
{
- if (ON_RB(&crq->rb_node)) {
- rb_erase(&crq->rb_node, &cfqq->sort_list);
- cfqq->queued[cfq_crq_is_sync(crq)]--;
- }
+ rb_erase(&crq->rb_node, &cfqq->sort_list);
+ cfqq->queued[cfq_crq_is_sync(crq)]--;
cfq_add_crq_rb(crq);
}
@@ -676,49 +651,28 @@ out:
return NULL;
}
-static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
+static void cfq_activate_request(request_queue_t *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_rq *crq = RQ_DATA(rq);
-
- if (crq) {
- struct cfq_queue *cfqq = crq->cfq_queue;
- if (cfq_crq_in_driver(crq)) {
- cfq_clear_crq_in_driver(crq);
- WARN_ON(!cfqd->rq_in_driver);
- cfqd->rq_in_driver--;
- }
- if (cfq_crq_in_flight(crq)) {
- const int sync = cfq_crq_is_sync(crq);
-
- cfq_clear_crq_in_flight(crq);
- WARN_ON(!cfqq->on_dispatch[sync]);
- cfqq->on_dispatch[sync]--;
- }
- cfq_mark_crq_requeued(crq);
- }
+ cfqd->rq_in_driver++;
}
-/*
- * make sure the service time gets corrected on reissue of this request
- */
-static void cfq_requeue_request(request_queue_t *q, struct request *rq)
+static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
{
- cfq_deactivate_request(q, rq);
- list_add(&rq->queuelist, &q->queue_head);
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+
+ WARN_ON(!cfqd->rq_in_driver);
+ cfqd->rq_in_driver--;
}
-static void cfq_remove_request(request_queue_t *q, struct request *rq)
+static void cfq_remove_request(struct request *rq)
{
struct cfq_rq *crq = RQ_DATA(rq);
- if (crq) {
- list_del_init(&rq->queuelist);
- cfq_del_crq_rb(crq);
- cfq_remove_merge_hints(q, crq);
-
- }
+ list_del_init(&rq->queuelist);
+ cfq_del_crq_rb(crq);
+ cfq_remove_merge_hints(rq->q, crq);
}
static int
@@ -762,7 +716,7 @@ static void cfq_merged_request(request_q
cfq_del_crq_hash(crq);
cfq_add_crq_hash(cfqd, crq);
- if (ON_RB(&crq->rb_node) && (rq_rb_key(req) != crq->rb_key)) {
+ if (rq_rb_key(req) != crq->rb_key) {
struct cfq_queue *cfqq = crq->cfq_queue;
cfq_update_next_crq(crq);
@@ -785,7 +739,7 @@ cfq_merged_requests(request_queue_t *q,
time_before(next->start_time, rq->start_time))
list_move(&rq->queuelist, &next->queuelist);
- cfq_remove_request(q, next);
+ cfq_remove_request(next);
}
static inline void
@@ -992,53 +946,16 @@ static int cfq_arm_slice_timer(struct cf
return 1;
}
-/*
- * we dispatch cfqd->cfq_quantum requests in total from the rr_list queues,
- * this function sector sorts the selected request to minimize seeks. we start
- * at cfqd->last_sector, not 0.
- */
-static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq)
+static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq,
+ int force)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = crq->cfq_queue;
- struct list_head *head = &q->queue_head, *entry = head;
- struct request *__rq;
- sector_t last;
-
- list_del(&crq->request->queuelist);
-
- last = cfqd->last_sector;
- list_for_each_entry_reverse(__rq, head, queuelist) {
- struct cfq_rq *__crq = RQ_DATA(__rq);
-
- if (blk_barrier_rq(__rq))
- break;
- if (!blk_fs_request(__rq))
- break;
- if (cfq_crq_requeued(__crq))
- break;
-
- if (__rq->sector <= crq->request->sector)
- break;
- if (__rq->sector > last && crq->request->sector < last) {
- last = crq->request->sector + crq->request->nr_sectors;
- break;
- }
- entry = &__rq->queuelist;
- }
-
- cfqd->last_sector = last;
cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
-
- cfq_del_crq_rb(crq);
- cfq_remove_merge_hints(q, crq);
-
- cfq_mark_crq_in_flight(crq);
- cfq_clear_crq_requeued(crq);
-
+ cfq_remove_request(crq->request);
cfqq->on_dispatch[cfq_crq_is_sync(crq)]++;
- list_add_tail(&crq->request->queuelist, entry);
+ elv_dispatch_insert(q, crq->request, force);
}
/*
@@ -1141,7 +1058,7 @@ keep_queue:
static int
__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- int max_dispatch)
+ int max_dispatch, int force)
{
int dispatched = 0;
@@ -1159,7 +1076,7 @@ __cfq_dispatch_requests(struct cfq_data
/*
* finally, insert request into driver dispatch list
*/
- cfq_dispatch_sort(cfqd->queue, crq);
+ cfq_dispatch_insert(cfqd->queue, crq, force);
cfqd->dispatch_slice++;
dispatched++;
@@ -1194,7 +1111,7 @@ __cfq_dispatch_requests(struct cfq_data
}
static int
-cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force)
+cfq_dispatch_requests(request_queue_t *q, int force)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq;
@@ -1204,106 +1121,31 @@ cfq_dispatch_requests(request_queue_t *q
cfqq = cfq_select_queue(cfqd, force);
if (cfqq) {
+ int max_dispatch;
+
+ /*
+ * if idle window is disabled, allow queue buildup
+ */
+ if (!cfq_cfqq_idle_window(cfqq) &&
+ cfqd->rq_in_driver >= cfqd->cfq_max_depth)
+ return 0;
+
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(cfqq);
del_timer(&cfqd->idle_slice_timer);
- if (cfq_class_idle(cfqq))
- max_dispatch = 1;
+ if (force)
+ max_dispatch = INT_MAX;
+ else
+ max_dispatch =
+ cfq_class_idle(cfqq) ? 1 : cfqd->cfq_quantum;
- return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
+ return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch, force);
}
return 0;
}
-static inline void cfq_account_dispatch(struct cfq_rq *crq)
-{
- struct cfq_queue *cfqq = crq->cfq_queue;
- struct cfq_data *cfqd = cfqq->cfqd;
-
- if (unlikely(!blk_fs_request(crq->request)))
- return;
-
- /*
- * accounted bit is necessary since some drivers will call
- * elv_next_request() many times for the same request (eg ide)
- */
- if (cfq_crq_in_driver(crq))
- return;
-
- cfq_mark_crq_in_driver(crq);
- cfqd->rq_in_driver++;
-}
-
-static inline void
-cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq)
-{
- struct cfq_data *cfqd = cfqq->cfqd;
- unsigned long now;
-
- if (!cfq_crq_in_driver(crq))
- return;
-
- now = jiffies;
-
- WARN_ON(!cfqd->rq_in_driver);
- cfqd->rq_in_driver--;
-
- if (!cfq_class_idle(cfqq))
- cfqd->last_end_request = now;
-
- if (!cfq_cfqq_dispatched(cfqq)) {
- if (cfq_cfqq_on_rr(cfqq)) {
- cfqq->service_last = now;
- cfq_resort_rr_list(cfqq, 0);
- }
- if (cfq_cfqq_expired(cfqq)) {
- __cfq_slice_expired(cfqd, cfqq, 0);
- cfq_schedule_dispatch(cfqd);
- }
- }
-
- if (cfq_crq_is_sync(crq))
- crq->io_context->last_end_request = now;
-}
-
-static struct request *cfq_next_request(request_queue_t *q)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct request *rq;
-
- if (!list_empty(&q->queue_head)) {
- struct cfq_rq *crq;
-dispatch:
- rq = list_entry_rq(q->queue_head.next);
-
- crq = RQ_DATA(rq);
- if (crq) {
- struct cfq_queue *cfqq = crq->cfq_queue;
-
- /*
- * if idle window is disabled, allow queue buildup
- */
- if (!cfq_crq_in_driver(crq) &&
- !cfq_cfqq_idle_window(cfqq) &&
- !blk_barrier_rq(rq) &&
- cfqd->rq_in_driver >= cfqd->cfq_max_depth)
- return NULL;
-
- cfq_remove_merge_hints(q, crq);
- cfq_account_dispatch(crq);
- }
-
- return rq;
- }
-
- if (cfq_dispatch_requests(q, cfqd->cfq_quantum, 0))
- goto dispatch;
-
- return NULL;
-}
-
/*
* task holds one reference to the queue, dropped when task exits. each crq
* in-flight on this queue also holds a reference, dropped when crq is freed.
@@ -1816,8 +1658,9 @@ cfq_crq_enqueued(struct cfq_data *cfqd,
}
}
-static void cfq_enqueue(struct cfq_data *cfqd, struct request *rq)
+static void cfq_insert_request(request_queue_t *q, struct request *rq)
{
+ struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);
struct cfq_queue *cfqq = crq->cfq_queue;
@@ -1837,56 +1680,37 @@ static void cfq_enqueue(struct cfq_data
cfq_crq_enqueued(cfqd, cfqq, crq);
}
-static void
-cfq_insert_request(request_queue_t *q, struct request *rq, int where)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
-
- switch (where) {
- case ELEVATOR_INSERT_BACK:
- while (cfq_dispatch_requests(q, INT_MAX, 1))
- ;
- list_add_tail(&rq->queuelist, &q->queue_head);
- /*
- * If we were idling with pending requests on
- * inactive cfqqs, force dispatching will
- * remove the idle timer and the queue won't
- * be kicked by __make_request() afterward.
- * Kick it here.
- */
- cfq_schedule_dispatch(cfqd);
- break;
- case ELEVATOR_INSERT_FRONT:
- list_add(&rq->queuelist, &q->queue_head);
- break;
- case ELEVATOR_INSERT_SORT:
- BUG_ON(!blk_fs_request(rq));
- cfq_enqueue(cfqd, rq);
- break;
- default:
- printk("%s: bad insert point %d\n", __FUNCTION__,where);
- return;
- }
-}
-
static void cfq_completed_request(request_queue_t *q, struct request *rq)
{
struct cfq_rq *crq = RQ_DATA(rq);
- struct cfq_queue *cfqq;
+ struct cfq_queue *cfqq = crq->cfq_queue;
+ struct cfq_data *cfqd = cfqq->cfqd;
+ const int sync = cfq_crq_is_sync(crq);
+ unsigned long now;
- if (unlikely(!blk_fs_request(rq)))
- return;
+ now = jiffies;
- cfqq = crq->cfq_queue;
+ WARN_ON(!cfqd->rq_in_driver);
+ WARN_ON(!cfqq->on_dispatch[sync]);
+ cfqd->rq_in_driver--;
+ cfqq->on_dispatch[sync]--;
- if (cfq_crq_in_flight(crq)) {
- const int sync = cfq_crq_is_sync(crq);
+ if (!cfq_class_idle(cfqq))
+ cfqd->last_end_request = now;
- WARN_ON(!cfqq->on_dispatch[sync]);
- cfqq->on_dispatch[sync]--;
+ if (!cfq_cfqq_dispatched(cfqq)) {
+ if (cfq_cfqq_on_rr(cfqq)) {
+ cfqq->service_last = now;
+ cfq_resort_rr_list(cfqq, 0);
+ }
+ if (cfq_cfqq_expired(cfqq)) {
+ __cfq_slice_expired(cfqd, cfqq, 0);
+ cfq_schedule_dispatch(cfqd);
+ }
}
- cfq_account_completion(cfqq, crq);
+ if (cfq_crq_is_sync(crq))
+ crq->io_context->last_end_request = now;
}
static struct request *
@@ -2118,9 +1942,6 @@ cfq_set_request(request_queue_t *q, stru
INIT_HLIST_NODE(&crq->hash);
crq->cfq_queue = cfqq;
crq->io_context = cic;
- cfq_clear_crq_in_flight(crq);
- cfq_clear_crq_in_driver(crq);
- cfq_clear_crq_requeued(crq);
if (rw == READ || process_sync(tsk))
cfq_mark_crq_is_sync(crq);
@@ -2201,7 +2022,7 @@ static void cfq_idle_slice_timer(unsigne
* only expire and reinvoke request handler, if there are
* other queues with pending requests
*/
- if (!cfq_pending_requests(cfqd)) {
+ if (!cfqd->busy_queues) {
cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end);
add_timer(&cfqd->idle_slice_timer);
goto out_cont;
@@ -2576,10 +2397,9 @@ static struct elevator_type iosched_cfq
.elevator_merge_fn = cfq_merge,
.elevator_merged_fn = cfq_merged_request,
.elevator_merge_req_fn = cfq_merged_requests,
- .elevator_next_req_fn = cfq_next_request,
+ .elevator_dispatch_fn = cfq_dispatch_requests,
.elevator_add_req_fn = cfq_insert_request,
- .elevator_remove_req_fn = cfq_remove_request,
- .elevator_requeue_req_fn = cfq_requeue_request,
+ .elevator_activate_req_fn = cfq_activate_request,
.elevator_deactivate_req_fn = cfq_deactivate_request,
.elevator_queue_empty_fn = cfq_queue_empty,
.elevator_completed_req_fn = cfq_completed_request,
-
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