diff options
Diffstat (limited to 'block/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 46 |
1 files changed, 40 insertions, 6 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 78c6b312bd3..07b70624377 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -219,9 +219,12 @@ static int cfq_queue_empty(request_queue_t *q) return !cfqd->busy_queues; } -static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) +static inline pid_t cfq_queue_pid(struct task_struct *task, int rw, int is_sync) { - if (rw == READ || rw == WRITE_SYNC) + /* + * Use the per-process queue, for read requests and syncronous writes + */ + if (!(rw & REQ_RW) || is_sync) return task->pid; return CFQ_KEY_ASYNC; @@ -473,7 +476,7 @@ static struct request * cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) { struct task_struct *tsk = current; - pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio)); + pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio), bio_sync(bio)); struct cfq_queue *cfqq; cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); @@ -565,6 +568,33 @@ cfq_merged_requests(request_queue_t *q, struct request *rq, cfq_remove_request(next); } +static int cfq_allow_merge(request_queue_t *q, struct request *rq, + struct bio *bio) +{ + struct cfq_data *cfqd = q->elevator->elevator_data; + const int rw = bio_data_dir(bio); + struct cfq_queue *cfqq; + pid_t key; + + /* + * Disallow merge of a sync bio into an async request. + */ + if ((bio_data_dir(bio) == READ || bio_sync(bio)) && !rq_is_sync(rq)) + return 0; + + /* + * Lookup the cfqq that this bio will be queued with. Allow + * merge only if rq is queued there. + */ + key = cfq_queue_pid(current, rw, bio_sync(bio)); + cfqq = cfq_find_cfq_hash(cfqd, key, current->ioprio); + + if (cfqq == RQ_CFQQ(rq)) + return 1; + + return 0; +} + static inline void __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) { @@ -1748,6 +1778,9 @@ static int cfq_may_queue(request_queue_t *q, int rw) struct cfq_data *cfqd = q->elevator->elevator_data; struct task_struct *tsk = current; struct cfq_queue *cfqq; + unsigned int key; + + key = cfq_queue_pid(tsk, rw, rw & REQ_RW_SYNC); /* * don't force setup of a queue from here, as a call to may_queue @@ -1755,7 +1788,7 @@ static int cfq_may_queue(request_queue_t *q, int rw) * so just lookup a possibly existing queue, or return 'may queue' * if that fails */ - cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); + cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); if (cfqq) { cfq_init_prio_data(cfqq); cfq_prio_boost(cfqq); @@ -1798,10 +1831,10 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask) struct task_struct *tsk = current; struct cfq_io_context *cic; const int rw = rq_data_dir(rq); - pid_t key = cfq_queue_pid(tsk, rw); + const int is_sync = rq_is_sync(rq); + pid_t key = cfq_queue_pid(tsk, rw, is_sync); struct cfq_queue *cfqq; unsigned long flags; - int is_sync = key != CFQ_KEY_ASYNC; might_sleep_if(gfp_mask & __GFP_WAIT); @@ -2119,6 +2152,7 @@ static struct elevator_type iosched_cfq = { .elevator_merge_fn = cfq_merge, .elevator_merged_fn = cfq_merged_request, .elevator_merge_req_fn = cfq_merged_requests, + .elevator_allow_merge_fn = cfq_allow_merge, .elevator_dispatch_fn = cfq_dispatch_requests, .elevator_add_req_fn = cfq_insert_request, .elevator_activate_req_fn = cfq_activate_request, |