[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>
diff --git a/drivers/block/cfq-iosched.c b/drivers/block/cfq-iosched.c
index cd056e7..7b14160 100644
--- a/drivers/block/cfq-iosched.c
+++ b/drivers/block/cfq-iosched.c
@@ -84,7 +84,6 @@
(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 @@
#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 @@
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 *);
static void cfq_put_cfqd(struct cfq_data *cfqd);
#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE)
@@ -347,18 +340,13 @@
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 @@
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- return !cfq_pending_requests(cfqd);
+ return !cfqd->busy_queues;
}
/*
@@ -386,11 +374,6 @@
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 @@
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 @@
* 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 @@
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 @@
* 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);
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 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 @@
return NULL;
}
+static void cfq_activate_request(request_queue_t *q, struct request *rq)
+{
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+
+ cfqd->rq_in_driver++;
+}
+
static void cfq_deactivate_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);
- }
+ WARN_ON(!cfqd->rq_in_driver);
+ 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)
-{
- cfq_deactivate_request(q, rq);
- list_add(&rq->queuelist, &q->queue_head);
-}
-
-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 @@
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 @@
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 +946,15 @@
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)
{
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_sort(q, crq->request);
}
/*
@@ -1159,7 +1075,7 @@
/*
* finally, insert request into driver dispatch list
*/
- cfq_dispatch_sort(cfqd->queue, crq);
+ cfq_dispatch_insert(cfqd->queue, crq);
cfqd->dispatch_slice++;
dispatched++;
@@ -1194,7 +1110,7 @@
}
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;
@@ -1204,12 +1120,25 @@
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 = cfqd->cfq_quantum;
+ if (cfq_class_idle(cfqq))
+ max_dispatch = 1;
+ } else
+ max_dispatch = INT_MAX;
return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
}
@@ -1217,93 +1146,6 @@
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 @@
}
}
-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 @@
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 @@
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 @@
* 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 @@
.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,