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;
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);
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)
{
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
* 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);
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);
.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,