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-rw-r--r--block/cfq-iosched.c53
1 files changed, 22 insertions, 31 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 0452108a932..c6e649f3cae 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -152,7 +152,6 @@ struct cfq_queue {
unsigned long slice_start;
unsigned long slice_end;
unsigned long slice_left;
- unsigned long service_last;
/* number of requests that are on the dispatch list */
int on_dispatch[2];
@@ -174,6 +173,7 @@ enum cfqq_state_flags {
CFQ_CFQQ_FLAG_fifo_expire,
CFQ_CFQQ_FLAG_idle_window,
CFQ_CFQQ_FLAG_prio_changed,
+ CFQ_CFQQ_FLAG_queue_new,
};
#define CFQ_CFQQ_FNS(name) \
@@ -198,6 +198,7 @@ CFQ_CFQQ_FNS(must_dispatch);
CFQ_CFQQ_FNS(fifo_expire);
CFQ_CFQQ_FNS(idle_window);
CFQ_CFQQ_FNS(prio_changed);
+CFQ_CFQQ_FNS(queue_new);
#undef CFQ_CFQQ_FNS
static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
@@ -350,7 +351,7 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
{
struct cfq_data *cfqd = cfqq->cfqd;
- struct list_head *list, *entry;
+ struct list_head *list;
BUG_ON(!cfq_cfqq_on_rr(cfqq));
@@ -375,31 +376,26 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
}
/*
- * if queue was preempted, just add to front to be fair. busy_rr
- * isn't sorted, but insert at the back for fairness.
+ * If this queue was preempted or is new (never been serviced), let
+ * it be added first for fairness but beind other new queues.
+ * Otherwise, just add to the back of the list.
*/
- if (preempted || list == &cfqd->busy_rr) {
- if (preempted)
- list = list->prev;
+ if (preempted || cfq_cfqq_queue_new(cfqq)) {
+ struct list_head *n = list;
+ struct cfq_queue *__cfqq;
- list_add_tail(&cfqq->cfq_list, list);
- return;
- }
+ while (n->next != list) {
+ __cfqq = list_entry_cfqq(n->next);
+ if (!cfq_cfqq_queue_new(__cfqq))
+ break;
- /*
- * sort by when queue was last serviced
- */
- entry = list;
- while ((entry = entry->prev) != list) {
- struct cfq_queue *__cfqq = list_entry_cfqq(entry);
+ n = n->next;
+ }
- if (!__cfqq->service_last)
- break;
- if (time_before(__cfqq->service_last, cfqq->service_last))
- break;
+ list = n;
}
- list_add(&cfqq->cfq_list, entry);
+ list_add_tail(&cfqq->cfq_list, list);
}
/*
@@ -591,13 +587,12 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
if (cfq_cfqq_wait_request(cfqq))
del_timer(&cfqd->idle_slice_timer);
- if (!preempted && !cfq_cfqq_dispatched(cfqq)) {
- cfqq->service_last = now;
+ if (!preempted && !cfq_cfqq_dispatched(cfqq))
cfq_schedule_dispatch(cfqd);
- }
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(cfqq);
+ cfq_clear_cfqq_queue_new(cfqq);
/*
* store what was left of this slice, if the queue idled out
@@ -1297,13 +1292,13 @@ retry:
hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
atomic_set(&cfqq->ref, 0);
cfqq->cfqd = cfqd;
- cfqq->service_last = 0;
/*
* set ->slice_left to allow preemption for a new process
*/
cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
cfq_mark_cfqq_idle_window(cfqq);
cfq_mark_cfqq_prio_changed(cfqq);
+ cfq_mark_cfqq_queue_new(cfqq);
cfq_init_prio_data(cfqq);
}
@@ -1672,12 +1667,8 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
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_dispatched(cfqq) && cfq_cfqq_on_rr(cfqq))
+ cfq_resort_rr_list(cfqq, 0);
if (sync)
RQ_CIC(rq)->last_end_request = now;