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-rw-r--r--block/cfq-iosched.c34
1 files changed, 29 insertions, 5 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f7364621613..1cc10489eaf 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -117,6 +117,7 @@ struct cfq_queue {
/* time when queue got scheduled in to dispatch first request. */
unsigned long dispatch_start;
+ unsigned int allocated_slice;
/* time when first request from queue completed and slice started. */
unsigned long slice_start;
unsigned long slice_end;
@@ -314,6 +315,8 @@ enum cfqq_state_flags {
CFQ_CFQQ_FLAG_sync, /* synchronous queue */
CFQ_CFQQ_FLAG_coop, /* cfqq is shared */
CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */
+ CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */
+ CFQ_CFQQ_FLAG_wait_busy_done, /* Got new request. Expire the queue */
};
#define CFQ_CFQQ_FNS(name) \
@@ -341,6 +344,8 @@ CFQ_CFQQ_FNS(slice_new);
CFQ_CFQQ_FNS(sync);
CFQ_CFQQ_FNS(coop);
CFQ_CFQQ_FNS(deep);
+CFQ_CFQQ_FNS(wait_busy);
+CFQ_CFQQ_FNS(wait_busy_done);
#undef CFQ_CFQQ_FNS
#ifdef CONFIG_DEBUG_CFQ_IOSCHED
@@ -578,6 +583,7 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
}
cfqq->slice_start = jiffies;
cfqq->slice_end = jiffies + slice;
+ cfqq->allocated_slice = slice;
cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
}
@@ -859,7 +865,7 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq)
{
- unsigned int slice_used, allocated_slice;
+ unsigned int slice_used;
/*
* Queue got expired before even a single request completed or
@@ -876,9 +882,8 @@ static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq)
1);
} else {
slice_used = jiffies - cfqq->slice_start;
- allocated_slice = cfqq->slice_end - cfqq->slice_start;
- if (slice_used > allocated_slice)
- slice_used = allocated_slice;
+ if (slice_used > cfqq->allocated_slice)
+ slice_used = cfqq->allocated_slice;
}
cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u sect=%lu", slice_used,
@@ -1495,6 +1500,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
cfq_log_cfqq(cfqd, cfqq, "set_active");
cfqq->slice_start = 0;
cfqq->dispatch_start = jiffies;
+ cfqq->allocated_slice = 0;
cfqq->slice_end = 0;
cfqq->slice_dispatch = 0;
cfqq->nr_sectors = 0;
@@ -1524,6 +1530,8 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
del_timer(&cfqd->idle_slice_timer);
cfq_clear_cfqq_wait_request(cfqq);
+ cfq_clear_cfqq_wait_busy(cfqq);
+ cfq_clear_cfqq_wait_busy_done(cfqq);
/*
* store what was left of this slice, if the queue idled/timed out
@@ -2066,7 +2074,8 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
/*
* The active queue has run out of time, expire it and select new.
*/
- if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq))
+ if ((cfq_slice_used(cfqq) || cfq_cfqq_wait_busy_done(cfqq))
+ && !cfq_cfqq_must_dispatch(cfqq))
goto expire;
/*
@@ -3096,6 +3105,10 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
if (cfqq == cfqd->active_queue) {
+ if (cfq_cfqq_wait_busy(cfqq)) {
+ cfq_clear_cfqq_wait_busy(cfqq);
+ cfq_mark_cfqq_wait_busy_done(cfqq);
+ }
/*
* Remember that we saw a request from this process, but
* don't start queuing just yet. Otherwise we risk seeing lots
@@ -3214,6 +3227,17 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
cfq_set_prio_slice(cfqd, cfqq);
cfq_clear_cfqq_slice_new(cfqq);
}
+
+ /*
+ * If this queue consumed its slice and this is last queue
+ * in the group, wait for next request before we expire
+ * the queue
+ */
+ if (cfq_slice_used(cfqq) && cfqq->cfqg->nr_cfqq == 1) {
+ cfqq->slice_end = jiffies + cfqd->cfq_slice_idle;
+ cfq_mark_cfqq_wait_busy(cfqq);
+ }
+
/*
* Idling is not enabled on:
* - expired queues