diff options
| -rw-r--r-- | block/cfq-iosched.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 11efcf196e74..a4809de6fea6 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -177,6 +177,7 @@ struct cfq_queue { enum cfqq_state_flags { CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ + CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ CFQ_CFQQ_FLAG_must_alloc, /* must be allowed rq alloc */ CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ @@ -202,6 +203,7 @@ static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ CFQ_CFQQ_FNS(on_rr); CFQ_CFQQ_FNS(wait_request); +CFQ_CFQQ_FNS(must_dispatch); CFQ_CFQQ_FNS(must_alloc); CFQ_CFQQ_FNS(must_alloc_slice); CFQ_CFQQ_FNS(fifo_expire); @@ -774,6 +776,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd, cfqq->slice_dispatch = 0; cfq_clear_cfqq_wait_request(cfqq); + cfq_clear_cfqq_must_dispatch(cfqq); cfq_clear_cfqq_must_alloc_slice(cfqq); cfq_clear_cfqq_fifo_expire(cfqq); cfq_mark_cfqq_slice_new(cfqq); @@ -1009,7 +1012,7 @@ 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)) + if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) goto expire; /* @@ -1173,6 +1176,7 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) */ cfq_dispatch_request(cfqd, cfqq); cfqq->slice_dispatch++; + cfq_clear_cfqq_must_dispatch(cfqq); /* * expire an async queue immediately if it has used up its slice. idle @@ -1898,14 +1902,13 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cfqq == cfqd->active_queue) { /* - * if we are waiting for a request for this queue, let it rip - * immediately and flag that we must not expire this queue - * just now + * Remember that we saw a request from this process, but + * don't start queuing just yet. Otherwise we risk seeing lots + * of tiny requests, because we disrupt the normal plugging + * and merging. */ - if (cfq_cfqq_wait_request(cfqq)) { - del_timer(&cfqd->idle_slice_timer); - blk_start_queueing(cfqd->queue); - } + if (cfq_cfqq_wait_request(cfqq)) + cfq_mark_cfqq_must_dispatch(cfqq); } else if (cfq_should_preempt(cfqd, cfqq, rq)) { /* * not the active queue - expire current slice if it is @@ -2175,6 +2178,12 @@ static void cfq_idle_slice_timer(unsigned long data) timed_out = 0; /* + * We saw a request before the queue expired, let it through + */ + if (cfq_cfqq_must_dispatch(cfqq)) + goto out_kick; + + /* * expired */ if (cfq_slice_used(cfqq)) |