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author | Jens Axboe <jens.axboe@oracle.com> | 2009-07-03 12:57:48 +0200 |
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committer | Jens Axboe <jens.axboe@oracle.com> | 2009-09-11 14:33:30 +0200 |
commit | 5ad531db6e0f3c3c985666e83d3c1c4d53acccf9 (patch) | |
tree | f5bd394c493f425e12fc6991d2b7adf2121ba506 /block/cfq-iosched.c | |
parent | scsi,block: update SCSI to handle mixed merge failures (diff) | |
download | linux-5ad531db6e0f3c3c985666e83d3c1c4d53acccf9.tar.xz linux-5ad531db6e0f3c3c985666e83d3c1c4d53acccf9.zip |
cfq-iosched: drain device queue before switching to a sync queue
To lessen the impact of async IO on sync IO, let the device drain of
any async IO in progress when switching to a sync cfqq that has idling
enabled.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to '')
-rw-r--r-- | block/cfq-iosched.c | 38 |
1 files changed, 25 insertions, 13 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index fd7080ed7935..93693bf6083e 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -140,7 +140,7 @@ struct cfq_data { */ unsigned int busy_rt_queues; - int rq_in_driver; + int rq_in_driver[2]; int sync_flight; /* @@ -239,6 +239,11 @@ static struct cfq_queue *cfq_get_queue(struct cfq_data *, int, static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, struct io_context *); +static inline int rq_in_driver(struct cfq_data *cfqd) +{ + return cfqd->rq_in_driver[0] + cfqd->rq_in_driver[1]; +} + static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, int is_sync) { @@ -760,9 +765,9 @@ static void cfq_activate_request(struct request_queue *q, struct request *rq) { struct cfq_data *cfqd = q->elevator->elevator_data; - cfqd->rq_in_driver++; + cfqd->rq_in_driver[rq_is_sync(rq)]++; cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", - cfqd->rq_in_driver); + rq_in_driver(cfqd)); cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); } @@ -770,11 +775,12 @@ static void cfq_activate_request(struct request_queue *q, struct request *rq) static void cfq_deactivate_request(struct request_queue *q, struct request *rq) { struct cfq_data *cfqd = q->elevator->elevator_data; + const int sync = rq_is_sync(rq); - WARN_ON(!cfqd->rq_in_driver); - cfqd->rq_in_driver--; + WARN_ON(!cfqd->rq_in_driver[sync]); + cfqd->rq_in_driver[sync]--; cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", - cfqd->rq_in_driver); + rq_in_driver(cfqd)); } static void cfq_remove_request(struct request *rq) @@ -1080,7 +1086,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) /* * still requests with the driver, don't idle */ - if (cfqd->rq_in_driver) + if (rq_in_driver(cfqd)) return; /* @@ -1312,6 +1318,12 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) return 0; /* + * Drain async requests before we start sync IO + */ + if (cfq_cfqq_idle_window(cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC]) + return 0; + + /* * If this is an async queue and we have sync IO in flight, let it wait */ if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq)) @@ -2130,11 +2142,11 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq) */ static void cfq_update_hw_tag(struct cfq_data *cfqd) { - if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak) - cfqd->rq_in_driver_peak = cfqd->rq_in_driver; + if (rq_in_driver(cfqd) > cfqd->rq_in_driver_peak) + cfqd->rq_in_driver_peak = rq_in_driver(cfqd); if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && - cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) + rq_in_driver(cfqd) <= CFQ_HW_QUEUE_MIN) return; if (cfqd->hw_tag_samples++ < 50) @@ -2161,9 +2173,9 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) cfq_update_hw_tag(cfqd); - WARN_ON(!cfqd->rq_in_driver); + WARN_ON(!cfqd->rq_in_driver[sync]); WARN_ON(!cfqq->dispatched); - cfqd->rq_in_driver--; + cfqd->rq_in_driver[sync]--; cfqq->dispatched--; if (cfq_cfqq_sync(cfqq)) @@ -2197,7 +2209,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) cfq_arm_slice_timer(cfqd); } - if (!cfqd->rq_in_driver) + if (!rq_in_driver(cfqd)) cfq_schedule_dispatch(cfqd); } |