diff options
| -rw-r--r-- | block/cfq-iosched.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 8917f2b3a783..70b48ea0e3e9 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -181,6 +181,8 @@ struct cfq_data { * Fallback dummy cfqq for extreme OOM conditions */ struct cfq_queue oom_cfqq; + + unsigned long last_end_sync_rq; }; enum cfqq_state_flags { @@ -1314,6 +1316,8 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) * Does this cfqq already have too much IO in flight? */ if (cfqq->dispatched >= max_dispatch) { + unsigned long load_at = cfqd->last_end_sync_rq + cfq_slice_sync; + /* * idle queue must always only have a single IO in flight */ @@ -1327,6 +1331,14 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) return 0; /* + * If a sync request has completed recently, don't overload + * the dispatch queue yet with async requests. + */ + if (cfqd->cfq_desktop && !cfq_cfqq_sync(cfqq) + && time_before(jiffies, load_at)) + return 0; + + /* * we are the only queue, allow up to 4 times of 'quantum' */ if (cfqq->dispatched >= 4 * max_dispatch) @@ -2158,8 +2170,10 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) if (cfq_cfqq_sync(cfqq)) cfqd->sync_flight--; - if (sync) + if (sync) { RQ_CIC(rq)->last_end_request = now; + cfqd->last_end_sync_rq = now; + } /* * If this is the active queue, check if it needs to be expired, @@ -2483,7 +2497,7 @@ static void *cfq_init_queue(struct request_queue *q) cfqd->cfq_slice_idle = cfq_slice_idle; cfqd->cfq_desktop = 1; cfqd->hw_tag = 1; - + cfqd->last_end_sync_rq = jiffies; return cfqd; } |