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cfq-iosched: development update
- Implement logic for detecting cooperating processes, so we choose the best available queue whenever possible. - Improve residual slice time accounting. - Remove dead code: we no longer see async requests coming in on sync queues. That part was removed a long time ago. That means that we can also remove the difference between cfq_cfqq_sync() and cfq_cfqq_class_sync(), they are now indentical. And we can kill the on_dispatch array, just make it a counter. - Allow a process to go into the current list, if it hasn't been serviced in this scheduler tick yet. Possible future improvements including caching the cfqq lookup in cfq_close_cooperator(), so we don't have to look it up twice. cfq_get_best_queue() should just use that last decision instead of doing it again. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
parent
1e3335de05
commit
6d048f5310
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@ -56,13 +56,7 @@ static struct completion *ioc_gone;
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#define ASYNC (0)
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#define ASYNC (0)
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#define SYNC (1)
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#define SYNC (1)
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#define cfq_cfqq_dispatched(cfqq) \
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#define cfq_cfqq_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
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((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
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#define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
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#define cfq_cfqq_sync(cfqq) \
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(cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
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#define sample_valid(samples) ((samples) > 80)
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#define sample_valid(samples) ((samples) > 80)
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@ -79,6 +73,7 @@ struct cfq_data {
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struct list_head busy_rr;
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struct list_head busy_rr;
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struct list_head cur_rr;
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struct list_head cur_rr;
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struct list_head idle_rr;
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struct list_head idle_rr;
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unsigned long cur_rr_tick;
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unsigned int busy_queues;
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unsigned int busy_queues;
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/*
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/*
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@ -98,11 +93,12 @@ struct cfq_data {
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struct cfq_queue *active_queue;
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struct cfq_queue *active_queue;
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struct cfq_io_context *active_cic;
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struct cfq_io_context *active_cic;
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int cur_prio, cur_end_prio;
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int cur_prio, cur_end_prio;
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unsigned long prio_time;
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unsigned int dispatch_slice;
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unsigned int dispatch_slice;
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struct timer_list idle_class_timer;
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struct timer_list idle_class_timer;
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sector_t last_sector;
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sector_t last_position;
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unsigned long last_end_request;
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unsigned long last_end_request;
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/*
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/*
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@ -117,6 +113,9 @@ struct cfq_data {
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unsigned int cfq_slice_idle;
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unsigned int cfq_slice_idle;
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struct list_head cic_list;
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struct list_head cic_list;
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sector_t new_seek_mean;
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u64 new_seek_total;
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};
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};
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/*
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/*
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@ -133,6 +132,8 @@ struct cfq_queue {
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unsigned int key;
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unsigned int key;
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/* member of the rr/busy/cur/idle cfqd list */
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/* member of the rr/busy/cur/idle cfqd list */
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struct list_head cfq_list;
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struct list_head cfq_list;
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/* in what tick we were last serviced */
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unsigned long rr_tick;
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/* sorted list of pending requests */
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/* sorted list of pending requests */
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struct rb_root sort_list;
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struct rb_root sort_list;
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/* if fifo isn't expired, next request to serve */
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/* if fifo isn't expired, next request to serve */
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@ -148,10 +149,11 @@ struct cfq_queue {
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unsigned long slice_end;
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unsigned long slice_end;
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unsigned long service_last;
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unsigned long service_last;
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unsigned long slice_start;
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long slice_resid;
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long slice_resid;
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/* number of requests that are on the dispatch list */
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/* number of requests that are on the dispatch list or inside driver */
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int on_dispatch[2];
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int dispatched;
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/* io prio of this group */
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/* io prio of this group */
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unsigned short ioprio, org_ioprio;
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unsigned short ioprio, org_ioprio;
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@ -159,6 +161,8 @@ struct cfq_queue {
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/* various state flags, see below */
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/* various state flags, see below */
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unsigned int flags;
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unsigned int flags;
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sector_t last_request_pos;
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};
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};
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enum cfqq_state_flags {
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enum cfqq_state_flags {
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@ -259,6 +263,8 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
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* easily introduce oscillations.
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* easily introduce oscillations.
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*/
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*/
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cfqq->slice_resid = 0;
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cfqq->slice_resid = 0;
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cfqq->slice_start = jiffies;
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}
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}
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/*
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/*
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@ -307,7 +313,7 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
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s1 = rq1->sector;
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s1 = rq1->sector;
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s2 = rq2->sector;
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s2 = rq2->sector;
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last = cfqd->last_sector;
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last = cfqd->last_position;
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/*
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/*
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* by definition, 1KiB is 2 sectors
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* by definition, 1KiB is 2 sectors
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@ -398,39 +404,42 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
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return cfq_choose_req(cfqd, next, prev);
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return cfq_choose_req(cfqd, next, prev);
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}
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}
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static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
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/*
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* This function finds out where to insert a BE queue in the service hierarchy
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*/
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static void cfq_resort_be_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
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int preempted)
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{
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{
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struct cfq_data *cfqd = cfqq->cfqd;
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struct list_head *list, *n;
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struct list_head *list, *n;
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struct cfq_queue *__cfqq;
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struct cfq_queue *__cfqq;
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int add_tail = 0;
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/*
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/*
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* Resorting requires the cfqq to be on the RR list already.
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* if cfqq has requests in flight, don't allow it to be
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* found in cfq_set_active_queue before it has finished them.
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* this is done to increase fairness between a process that
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* has lots of io pending vs one that only generates one
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* sporadically or synchronously
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*/
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*/
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if (!cfq_cfqq_on_rr(cfqq))
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if (cfqq->dispatched)
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return;
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list = &cfqd->busy_rr;
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else if (cfqq->ioprio == (cfqd->cur_prio + 1) &&
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list_del(&cfqq->cfq_list);
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cfq_cfqq_sync(cfqq) &&
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(time_before(cfqd->prio_time, cfqq->service_last) ||
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if (cfq_class_rt(cfqq))
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cfq_cfqq_queue_new(cfqq) || preempted)) {
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list = &cfqd->cur_rr;
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list = &cfqd->cur_rr;
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else if (cfq_class_idle(cfqq))
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add_tail = 1;
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list = &cfqd->idle_rr;
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} else
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else {
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list = &cfqd->rr_list[cfqq->ioprio];
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/*
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* if cfqq has requests in flight, don't allow it to be
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* found in cfq_set_active_queue before it has finished them.
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* this is done to increase fairness between a process that
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* has lots of io pending vs one that only generates one
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* sporadically or synchronously
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*/
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if (cfq_cfqq_dispatched(cfqq))
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list = &cfqd->busy_rr;
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else
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list = &cfqd->rr_list[cfqq->ioprio];
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}
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if (preempted || cfq_cfqq_queue_new(cfqq)) {
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if (!cfq_cfqq_sync(cfqq) || add_tail) {
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/*
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* async queue always goes to the end. this wont be overly
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* unfair to writes, as the sort of the sync queue wont be
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* allowed to pass the async queue again.
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*/
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list_add_tail(&cfqq->cfq_list, list);
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} else if (preempted || cfq_cfqq_queue_new(cfqq)) {
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/*
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/*
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* If this queue was preempted or is new (never been serviced),
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* If this queue was preempted or is new (never been serviced),
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* let it be added first for fairness but beind other new
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* let it be added first for fairness but beind other new
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@ -444,14 +453,7 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
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n = n->next;
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n = n->next;
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}
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}
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list_add_tail(&cfqq->cfq_list, n);
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list_add(&cfqq->cfq_list, n);
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} else if (!cfq_cfqq_class_sync(cfqq)) {
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/*
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* async queue always goes to the end. this wont be overly
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* unfair to writes, as the sort of the sync queue wont be
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* allowed to pass the async queue again.
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*/
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list_add_tail(&cfqq->cfq_list, list);
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} else {
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} else {
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/*
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/*
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* sort by last service, but don't cross a new or async
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* sort by last service, but don't cross a new or async
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@ -461,17 +463,54 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
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*/
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*/
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n = list;
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n = list;
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while ((n = n->prev) != list) {
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while ((n = n->prev) != list) {
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struct cfq_queue *__cfqq = list_entry_cfqq(n);
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struct cfq_queue *__c = list_entry_cfqq(n);
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if (!cfq_cfqq_class_sync(cfqq) || !__cfqq->service_last)
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if (!cfq_cfqq_sync(__c) || !__c->service_last)
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break;
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break;
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if (time_before(__cfqq->service_last, cfqq->service_last))
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if (time_before(__c->service_last, cfqq->service_last))
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break;
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break;
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}
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}
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list_add(&cfqq->cfq_list, n);
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list_add(&cfqq->cfq_list, n);
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}
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}
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}
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}
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static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
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{
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struct cfq_data *cfqd = cfqq->cfqd;
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struct list_head *n;
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/*
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* Resorting requires the cfqq to be on the RR list already.
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*/
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if (!cfq_cfqq_on_rr(cfqq))
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return;
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list_del(&cfqq->cfq_list);
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if (cfq_class_rt(cfqq)) {
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/*
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* At to the front of the current list, but behind other
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* RT queues.
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*/
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n = &cfqd->cur_rr;
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while (n->next != &cfqd->cur_rr)
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if (!cfq_class_rt(cfqq))
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break;
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list_add(&cfqq->cfq_list, n);
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} else if (cfq_class_idle(cfqq)) {
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/*
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* IDLE goes to the tail of the idle list
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*/
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list_add_tail(&cfqq->cfq_list, &cfqd->idle_rr);
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} else {
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/*
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* So we get here, ergo the queue is a regular best-effort queue
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*/
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cfq_resort_be_queue(cfqd, cfqq, preempted);
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}
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}
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/*
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/*
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* add to busy list of queues for service, trying to be fair in ordering
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* add to busy list of queues for service, trying to be fair in ordering
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* the pending list according to last request service
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* the pending list according to last request service
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@ -579,6 +618,8 @@ static void cfq_activate_request(request_queue_t *q, struct request *rq)
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*/
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*/
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if (!cfqd->hw_tag && cfqd->rq_in_driver > 4)
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if (!cfqd->hw_tag && cfqd->rq_in_driver > 4)
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cfqd->hw_tag = 1;
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cfqd->hw_tag = 1;
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cfqd->last_position = rq->hard_sector + rq->hard_nr_sectors;
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}
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}
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static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
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static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
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@ -684,6 +725,7 @@ __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
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cfq_clear_cfqq_must_alloc_slice(cfqq);
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cfq_clear_cfqq_must_alloc_slice(cfqq);
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cfq_clear_cfqq_fifo_expire(cfqq);
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cfq_clear_cfqq_fifo_expire(cfqq);
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cfq_mark_cfqq_slice_new(cfqq);
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cfq_mark_cfqq_slice_new(cfqq);
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cfqq->rr_tick = cfqd->cur_rr_tick;
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}
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}
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cfqd->active_queue = cfqq;
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cfqd->active_queue = cfqq;
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@ -786,10 +828,46 @@ static int cfq_get_next_prio_level(struct cfq_data *cfqd)
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cfqd->cur_end_prio = 0;
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cfqd->cur_end_prio = 0;
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}
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}
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cfqd->cur_rr_tick++;
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cfqd->prio_time = jiffies;
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return prio;
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return prio;
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}
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}
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static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
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static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
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struct request *rq)
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{
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if (rq->sector >= cfqd->last_position)
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return rq->sector - cfqd->last_position;
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else
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return cfqd->last_position - rq->sector;
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}
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static struct cfq_queue *cfq_get_best_queue(struct cfq_data *cfqd)
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{
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struct cfq_queue *cfqq = NULL, *__cfqq;
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sector_t best = -1, dist;
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list_for_each_entry(__cfqq, &cfqd->cur_rr, cfq_list) {
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if (!__cfqq->next_rq || !cfq_cfqq_sync(__cfqq))
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continue;
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dist = cfq_dist_from_last(cfqd, __cfqq->next_rq);
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if (dist < best) {
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best = dist;
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cfqq = __cfqq;
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}
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}
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/*
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* Only async queue(s) available, grab first entry
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*/
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if (!cfqq)
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cfqq = list_entry_cfqq(cfqd->cur_rr.next);
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return cfqq;
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}
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static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
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{
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{
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struct cfq_queue *cfqq = NULL;
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struct cfq_queue *cfqq = NULL;
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@ -799,7 +877,7 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
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* empty, get next prio level and grab first entry then if any
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* empty, get next prio level and grab first entry then if any
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* are spliced
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* are spliced
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*/
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*/
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cfqq = list_entry_cfqq(cfqd->cur_rr.next);
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cfqq = cfq_get_best_queue(cfqd);
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} else if (!list_empty(&cfqd->busy_rr)) {
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} else if (!list_empty(&cfqd->busy_rr)) {
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/*
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/*
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* If no new queues are available, check if the busy list has
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* If no new queues are available, check if the busy list has
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@ -820,49 +898,128 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
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mod_timer(&cfqd->idle_class_timer, end);
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mod_timer(&cfqd->idle_class_timer, end);
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}
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}
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return cfqq;
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}
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static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
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{
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struct cfq_queue *cfqq;
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do {
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long prio;
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cfqq = cfq_get_next_queue(cfqd);
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if (!cfqq)
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break;
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|
prio = cfq_prio_to_slice(cfqd, cfqq);
|
||||||
|
if (cfqq->slice_resid > -prio)
|
||||||
|
break;
|
||||||
|
|
||||||
|
cfqq->slice_resid += prio;
|
||||||
|
list_del_init(&cfqq->cfq_list);
|
||||||
|
list_add_tail(&cfqq->cfq_list, &cfqd->rr_list[cfqq->ioprio]);
|
||||||
|
cfqq = NULL;
|
||||||
|
} while (1);
|
||||||
|
|
||||||
__cfq_set_active_queue(cfqd, cfqq);
|
__cfq_set_active_queue(cfqd, cfqq);
|
||||||
return cfqq;
|
return cfqq;
|
||||||
}
|
}
|
||||||
|
|
||||||
#define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024))
|
static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq)
|
||||||
|
{
|
||||||
|
struct cfq_io_context *cic = cfqd->active_cic;
|
||||||
|
|
||||||
static int cfq_arm_slice_timer(struct cfq_data *cfqd)
|
if (!sample_valid(cic->seek_samples))
|
||||||
|
return 0;
|
||||||
|
|
||||||
|
return cfq_dist_from_last(cfqd, rq) <= cic->seek_mean;
|
||||||
|
}
|
||||||
|
|
||||||
|
static struct cfq_queue *__cfq_close_cooperator(struct cfq_data *cfqd,
|
||||||
|
struct cfq_queue *cur_cfqq,
|
||||||
|
struct list_head *list)
|
||||||
|
{
|
||||||
|
struct cfq_queue *cfqq;
|
||||||
|
|
||||||
|
list_for_each_entry(cfqq, list, cfq_list) {
|
||||||
|
if (cfqq == cur_cfqq || !cfq_cfqq_sync(cfqq))
|
||||||
|
continue;
|
||||||
|
|
||||||
|
BUG_ON(!cfqq->next_rq);
|
||||||
|
|
||||||
|
if (cfq_rq_close(cfqd, cfqq->next_rq))
|
||||||
|
return cfqq;
|
||||||
|
}
|
||||||
|
|
||||||
|
return NULL;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int cfq_close_cooperator(struct cfq_data *cfqd,
|
||||||
|
struct cfq_queue *cur_cfqq)
|
||||||
|
{
|
||||||
|
struct cfq_queue *cfqq;
|
||||||
|
|
||||||
|
if (!cfqd->busy_queues)
|
||||||
|
return 0;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* check cur_rr and same-prio rr_list for candidates
|
||||||
|
*/
|
||||||
|
cfqq = __cfq_close_cooperator(cfqd, cur_cfqq, &cfqd->cur_rr);
|
||||||
|
if (cfqq)
|
||||||
|
return 1;
|
||||||
|
|
||||||
|
cfqq = __cfq_close_cooperator(cfqd, cur_cfqq, &cfqd->rr_list[cur_cfqq->ioprio]);
|
||||||
|
if (cfqq && (cfqq->rr_tick == cfqd->cur_rr_tick))
|
||||||
|
cfqq = NULL;
|
||||||
|
|
||||||
|
return cfqq != NULL;
|
||||||
|
}
|
||||||
|
|
||||||
|
#define CIC_SEEKY(cic) ((cic)->seek_mean > (8 * 1024))
|
||||||
|
|
||||||
|
static void cfq_arm_slice_timer(struct cfq_data *cfqd)
|
||||||
{
|
{
|
||||||
struct cfq_queue *cfqq = cfqd->active_queue;
|
struct cfq_queue *cfqq = cfqd->active_queue;
|
||||||
struct cfq_io_context *cic;
|
struct cfq_io_context *cic;
|
||||||
unsigned long sl;
|
unsigned long sl;
|
||||||
|
|
||||||
WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
|
WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
|
||||||
|
WARN_ON(cfq_cfqq_slice_new(cfqq));
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* idle is disabled, either manually or by past process history
|
* idle is disabled, either manually or by past process history
|
||||||
*/
|
*/
|
||||||
if (!cfqd->cfq_slice_idle)
|
if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq))
|
||||||
return 0;
|
return;
|
||||||
if (!cfq_cfqq_idle_window(cfqq))
|
|
||||||
return 0;
|
|
||||||
/*
|
/*
|
||||||
* task has exited, don't wait
|
* task has exited, don't wait
|
||||||
*/
|
*/
|
||||||
cic = cfqd->active_cic;
|
cic = cfqd->active_cic;
|
||||||
if (!cic || !cic->ioc->task)
|
if (!cic || !cic->ioc->task)
|
||||||
return 0;
|
return;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* See if this prio level has a good candidate
|
||||||
|
*/
|
||||||
|
if (cfq_close_cooperator(cfqd, cfqq))
|
||||||
|
return;
|
||||||
|
|
||||||
cfq_mark_cfqq_must_dispatch(cfqq);
|
cfq_mark_cfqq_must_dispatch(cfqq);
|
||||||
cfq_mark_cfqq_wait_request(cfqq);
|
cfq_mark_cfqq_wait_request(cfqq);
|
||||||
|
|
||||||
sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
|
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* we don't want to idle for seeks, but we do want to allow
|
* we don't want to idle for seeks, but we do want to allow
|
||||||
* fair distribution of slice time for a process doing back-to-back
|
* fair distribution of slice time for a process doing back-to-back
|
||||||
* seeks. so allow a little bit of time for him to submit a new rq
|
* seeks. so allow a little bit of time for him to submit a new rq
|
||||||
*/
|
*/
|
||||||
|
sl = cfqd->cfq_slice_idle;
|
||||||
if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
|
if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
|
||||||
sl = min(sl, msecs_to_jiffies(2));
|
sl = min(sl, msecs_to_jiffies(2));
|
||||||
|
|
||||||
mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
|
mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
|
||||||
return 1;
|
|
||||||
}
|
}
|
||||||
|
|
||||||
static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
|
static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
|
||||||
|
@ -870,7 +1027,7 @@ static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
|
||||||
struct cfq_queue *cfqq = RQ_CFQQ(rq);
|
struct cfq_queue *cfqq = RQ_CFQQ(rq);
|
||||||
|
|
||||||
cfq_remove_request(rq);
|
cfq_remove_request(rq);
|
||||||
cfqq->on_dispatch[rq_is_sync(rq)]++;
|
cfqq->dispatched++;
|
||||||
elv_dispatch_sort(q, rq);
|
elv_dispatch_sort(q, rq);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -891,13 +1048,13 @@ static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq)
|
||||||
if (list_empty(&cfqq->fifo))
|
if (list_empty(&cfqq->fifo))
|
||||||
return NULL;
|
return NULL;
|
||||||
|
|
||||||
fifo = cfq_cfqq_class_sync(cfqq);
|
fifo = cfq_cfqq_sync(cfqq);
|
||||||
rq = rq_entry_fifo(cfqq->fifo.next);
|
rq = rq_entry_fifo(cfqq->fifo.next);
|
||||||
|
|
||||||
if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
|
if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
|
||||||
return rq;
|
return NULL;
|
||||||
|
|
||||||
return NULL;
|
return rq;
|
||||||
}
|
}
|
||||||
|
|
||||||
static inline int
|
static inline int
|
||||||
|
@ -922,23 +1079,26 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
|
||||||
goto new_queue;
|
goto new_queue;
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* slice has expired
|
* The active queue has run out of time, expire it and select new.
|
||||||
*/
|
*/
|
||||||
if (!cfq_cfqq_must_dispatch(cfqq) && cfq_slice_used(cfqq))
|
if (cfq_slice_used(cfqq))
|
||||||
goto expire;
|
goto expire;
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* if queue has requests, dispatch one. if not, check if
|
* The active queue has requests and isn't expired, allow it to
|
||||||
* enough slice is left to wait for one
|
* dispatch.
|
||||||
*/
|
*/
|
||||||
if (!RB_EMPTY_ROOT(&cfqq->sort_list))
|
if (!RB_EMPTY_ROOT(&cfqq->sort_list))
|
||||||
goto keep_queue;
|
goto keep_queue;
|
||||||
else if (cfq_cfqq_slice_new(cfqq) || cfq_cfqq_dispatched(cfqq)) {
|
|
||||||
|
/*
|
||||||
|
* No requests pending. If the active queue still has requests in
|
||||||
|
* flight or is idling for a new request, allow either of these
|
||||||
|
* conditions to happen (or time out) before selecting a new queue.
|
||||||
|
*/
|
||||||
|
if (cfqq->dispatched || timer_pending(&cfqd->idle_slice_timer)) {
|
||||||
cfqq = NULL;
|
cfqq = NULL;
|
||||||
goto keep_queue;
|
goto keep_queue;
|
||||||
} else if (cfq_cfqq_class_sync(cfqq)) {
|
|
||||||
if (cfq_arm_slice_timer(cfqd))
|
|
||||||
return NULL;
|
|
||||||
}
|
}
|
||||||
|
|
||||||
expire:
|
expire:
|
||||||
|
@ -1039,7 +1199,7 @@ static int
|
||||||
cfq_dispatch_requests(request_queue_t *q, int force)
|
cfq_dispatch_requests(request_queue_t *q, int force)
|
||||||
{
|
{
|
||||||
struct cfq_data *cfqd = q->elevator->elevator_data;
|
struct cfq_data *cfqd = q->elevator->elevator_data;
|
||||||
struct cfq_queue *cfqq, *prev_cfqq;
|
struct cfq_queue *cfqq;
|
||||||
int dispatched;
|
int dispatched;
|
||||||
|
|
||||||
if (!cfqd->busy_queues)
|
if (!cfqd->busy_queues)
|
||||||
|
@ -1049,23 +1209,19 @@ cfq_dispatch_requests(request_queue_t *q, int force)
|
||||||
return cfq_forced_dispatch(cfqd);
|
return cfq_forced_dispatch(cfqd);
|
||||||
|
|
||||||
dispatched = 0;
|
dispatched = 0;
|
||||||
prev_cfqq = NULL;
|
|
||||||
while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
|
while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
|
||||||
int max_dispatch;
|
int max_dispatch;
|
||||||
|
|
||||||
if (cfqd->busy_queues > 1) {
|
if (cfqd->busy_queues > 1) {
|
||||||
/*
|
|
||||||
* Don't repeat dispatch from the previous queue.
|
|
||||||
*/
|
|
||||||
if (prev_cfqq == cfqq)
|
|
||||||
break;
|
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* So we have dispatched before in this round, if the
|
* So we have dispatched before in this round, if the
|
||||||
* next queue has idling enabled (must be sync), don't
|
* next queue has idling enabled (must be sync), don't
|
||||||
* allow it service until the previous have continued.
|
* allow it service until the previous have completed.
|
||||||
*/
|
*/
|
||||||
if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
|
if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq) &&
|
||||||
|
dispatched)
|
||||||
|
break;
|
||||||
|
if (cfqq->dispatched >= cfqd->cfq_quantum)
|
||||||
break;
|
break;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -1078,7 +1234,6 @@ cfq_dispatch_requests(request_queue_t *q, int force)
|
||||||
max_dispatch = 1;
|
max_dispatch = 1;
|
||||||
|
|
||||||
dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
|
dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
|
||||||
prev_cfqq = cfqq;
|
|
||||||
}
|
}
|
||||||
|
|
||||||
return dispatched;
|
return dispatched;
|
||||||
|
@ -1520,7 +1675,8 @@ cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
|
||||||
}
|
}
|
||||||
|
|
||||||
static void
|
static void
|
||||||
cfq_update_io_seektime(struct cfq_io_context *cic, struct request *rq)
|
cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
|
||||||
|
struct request *rq)
|
||||||
{
|
{
|
||||||
sector_t sdist;
|
sector_t sdist;
|
||||||
u64 total;
|
u64 total;
|
||||||
|
@ -1530,6 +1686,11 @@ cfq_update_io_seektime(struct cfq_io_context *cic, struct request *rq)
|
||||||
else
|
else
|
||||||
sdist = cic->last_request_pos - rq->sector;
|
sdist = cic->last_request_pos - rq->sector;
|
||||||
|
|
||||||
|
if (!cic->seek_samples) {
|
||||||
|
cfqd->new_seek_total = (7*cic->seek_total + (u64)256*sdist) / 8;
|
||||||
|
cfqd->new_seek_mean = cfqd->new_seek_total / 256;
|
||||||
|
}
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* Don't allow the seek distance to get too large from the
|
* Don't allow the seek distance to get too large from the
|
||||||
* odd fragment, pagein, etc
|
* odd fragment, pagein, etc
|
||||||
|
@ -1580,13 +1741,16 @@ static int
|
||||||
cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
|
cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
|
||||||
struct request *rq)
|
struct request *rq)
|
||||||
{
|
{
|
||||||
struct cfq_queue *cfqq = cfqd->active_queue;
|
struct cfq_queue *cfqq;
|
||||||
sector_t dist;
|
|
||||||
|
|
||||||
if (cfq_class_idle(new_cfqq))
|
cfqq = cfqd->active_queue;
|
||||||
|
if (!cfqq)
|
||||||
return 0;
|
return 0;
|
||||||
|
|
||||||
if (!cfqq)
|
if (cfq_slice_used(cfqq))
|
||||||
|
return 1;
|
||||||
|
|
||||||
|
if (cfq_class_idle(new_cfqq))
|
||||||
return 0;
|
return 0;
|
||||||
|
|
||||||
if (cfq_class_idle(cfqq))
|
if (cfq_class_idle(cfqq))
|
||||||
|
@ -1613,12 +1777,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
|
||||||
* if this request is as-good as one we would expect from the
|
* if this request is as-good as one we would expect from the
|
||||||
* current cfqq, let it preempt
|
* current cfqq, let it preempt
|
||||||
*/
|
*/
|
||||||
if (rq->sector > cfqd->last_sector)
|
if (cfq_rq_close(cfqd, rq))
|
||||||
dist = rq->sector - cfqd->last_sector;
|
|
||||||
else
|
|
||||||
dist = cfqd->last_sector - rq->sector;
|
|
||||||
|
|
||||||
if (dist <= cfqd->active_cic->seek_mean)
|
|
||||||
return 1;
|
return 1;
|
||||||
|
|
||||||
return 0;
|
return 0;
|
||||||
|
@ -1656,28 +1815,12 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
|
||||||
if (rq_is_meta(rq))
|
if (rq_is_meta(rq))
|
||||||
cfqq->meta_pending++;
|
cfqq->meta_pending++;
|
||||||
|
|
||||||
/*
|
|
||||||
* we never wait for an async request and we don't allow preemption
|
|
||||||
* of an async request. so just return early
|
|
||||||
*/
|
|
||||||
if (!rq_is_sync(rq)) {
|
|
||||||
/*
|
|
||||||
* sync process issued an async request, if it's waiting
|
|
||||||
* then expire it and kick rq handling.
|
|
||||||
*/
|
|
||||||
if (cic == cfqd->active_cic &&
|
|
||||||
del_timer(&cfqd->idle_slice_timer)) {
|
|
||||||
cfq_slice_expired(cfqd, 0, 0);
|
|
||||||
blk_start_queueing(cfqd->queue);
|
|
||||||
}
|
|
||||||
return;
|
|
||||||
}
|
|
||||||
|
|
||||||
cfq_update_io_thinktime(cfqd, cic);
|
cfq_update_io_thinktime(cfqd, cic);
|
||||||
cfq_update_io_seektime(cic, rq);
|
cfq_update_io_seektime(cfqd, cic, rq);
|
||||||
cfq_update_idle_window(cfqd, cfqq, cic);
|
cfq_update_idle_window(cfqd, cfqq, cic);
|
||||||
|
|
||||||
cic->last_request_pos = rq->sector + rq->nr_sectors;
|
cic->last_request_pos = rq->sector + rq->nr_sectors;
|
||||||
|
cfqq->last_request_pos = cic->last_request_pos;
|
||||||
|
|
||||||
if (cfqq == cfqd->active_queue) {
|
if (cfqq == cfqd->active_queue) {
|
||||||
/*
|
/*
|
||||||
|
@ -1726,13 +1869,11 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
|
||||||
now = jiffies;
|
now = jiffies;
|
||||||
|
|
||||||
WARN_ON(!cfqd->rq_in_driver);
|
WARN_ON(!cfqd->rq_in_driver);
|
||||||
WARN_ON(!cfqq->on_dispatch[sync]);
|
WARN_ON(!cfqq->dispatched);
|
||||||
cfqd->rq_in_driver--;
|
cfqd->rq_in_driver--;
|
||||||
cfqq->on_dispatch[sync]--;
|
cfqq->dispatched--;
|
||||||
cfqq->service_last = now;
|
cfqq->service_last = now;
|
||||||
|
|
||||||
cfqd->last_sector = rq->hard_sector + rq->hard_nr_sectors;
|
|
||||||
|
|
||||||
if (!cfq_class_idle(cfqq))
|
if (!cfq_class_idle(cfqq))
|
||||||
cfqd->last_end_request = now;
|
cfqd->last_end_request = now;
|
||||||
|
|
||||||
|
@ -1752,11 +1893,12 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
|
||||||
}
|
}
|
||||||
if (cfq_slice_used(cfqq))
|
if (cfq_slice_used(cfqq))
|
||||||
cfq_slice_expired(cfqd, 0, 1);
|
cfq_slice_expired(cfqd, 0, 1);
|
||||||
else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) {
|
else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list))
|
||||||
if (!cfq_arm_slice_timer(cfqd))
|
cfq_arm_slice_timer(cfqd);
|
||||||
cfq_schedule_dispatch(cfqd);
|
|
||||||
}
|
|
||||||
}
|
}
|
||||||
|
|
||||||
|
if (!cfqd->rq_in_driver)
|
||||||
|
cfq_schedule_dispatch(cfqd);
|
||||||
}
|
}
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
@ -2101,7 +2243,6 @@ fail:
|
||||||
/*
|
/*
|
||||||
* sysfs parts below -->
|
* sysfs parts below -->
|
||||||
*/
|
*/
|
||||||
|
|
||||||
static ssize_t
|
static ssize_t
|
||||||
cfq_var_show(unsigned int var, char *page)
|
cfq_var_show(unsigned int var, char *page)
|
||||||
{
|
{
|
||||||
|
|
Loading…
Reference in New Issue
Block a user