diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/cfq-iosched.c | 117 |
1 files changed, 34 insertions, 83 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 8830893e062..8fe1a0ddb51 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -26,9 +26,9 @@ static const int cfq_slice_async_rq = 2; static int cfq_slice_idle = HZ / 125; /* - * grace period before allowing idle class to get disk access + * offset from end of service tree */ -#define CFQ_IDLE_GRACE (HZ / 10) +#define CFQ_IDLE_DELAY (HZ / 5) /* * below this threshold, we consider thinktime immediate @@ -98,8 +98,6 @@ struct cfq_data { struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; struct cfq_queue *async_idle_cfqq; - struct timer_list idle_class_timer; - sector_t last_position; unsigned long last_end_request; @@ -384,12 +382,15 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2) /* * The below is leftmost cache rbtree addon */ -static struct rb_node *cfq_rb_first(struct cfq_rb_root *root) +static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) { if (!root->left) root->left = rb_first(&root->rb); - return root->left; + if (root->left) + return rb_entry(root->left, struct cfq_queue, rb_node); + + return NULL; } static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) @@ -446,12 +447,20 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd, static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, int add_front) { - struct rb_node **p = &cfqd->service_tree.rb.rb_node; - struct rb_node *parent = NULL; + struct rb_node **p, *parent; + struct cfq_queue *__cfqq; unsigned long rb_key; int left; - if (!add_front) { + if (cfq_class_idle(cfqq)) { + rb_key = CFQ_IDLE_DELAY; + parent = rb_last(&cfqd->service_tree.rb); + if (parent && parent != &cfqq->rb_node) { + __cfqq = rb_entry(parent, struct cfq_queue, rb_node); + rb_key += __cfqq->rb_key; + } else + rb_key += jiffies; + } else if (!add_front) { rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; rb_key += cfqq->slice_resid; cfqq->slice_resid = 0; @@ -469,8 +478,9 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, } left = 1; + parent = NULL; + p = &cfqd->service_tree.rb.rb_node; while (*p) { - struct cfq_queue *__cfqq; struct rb_node **n; parent = *p; @@ -736,11 +746,6 @@ static inline void __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) { if (cfqq) { - /* - * stop potential idle class queues waiting service - */ - del_timer(&cfqd->idle_class_timer); - cfqq->slice_end = 0; cfq_clear_cfqq_must_alloc_slice(cfqq); cfq_clear_cfqq_fifo_expire(cfqq); @@ -789,47 +794,16 @@ static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out) __cfq_slice_expired(cfqd, cfqq, timed_out); } -static int start_idle_class_timer(struct cfq_data *cfqd) -{ - unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; - unsigned long now = jiffies; - - if (time_before(now, end) && - time_after_eq(now, cfqd->last_end_request)) { - mod_timer(&cfqd->idle_class_timer, end); - return 1; - } - - return 0; -} - /* * Get next queue for service. Unless we have a queue preemption, * we'll simply select the first cfqq in the service tree. */ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) { - struct cfq_queue *cfqq; - struct rb_node *n; - if (RB_EMPTY_ROOT(&cfqd->service_tree.rb)) return NULL; - n = cfq_rb_first(&cfqd->service_tree); - cfqq = rb_entry(n, struct cfq_queue, rb_node); - - if (cfq_class_idle(cfqq)) { - /* - * if we have idle queues and no rt or be queues had - * pending requests, either allow immediate service if - * the grace period has passed or arm the idle grace - * timer - */ - if (start_idle_class_timer(cfqd)) - cfqq = NULL; - } - - return cfqq; + return cfq_rb_first(&cfqd->service_tree); } /* @@ -1087,14 +1061,11 @@ static inline int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) */ static int cfq_forced_dispatch(struct cfq_data *cfqd) { + struct cfq_queue *cfqq; int dispatched = 0; - struct rb_node *n; - - while ((n = cfq_rb_first(&cfqd->service_tree)) != NULL) { - struct cfq_queue *cfqq = rb_entry(n, struct cfq_queue, rb_node); + while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL) dispatched += __cfq_forced_dispatch_cfqq(cfqq); - } cfq_slice_expired(cfqd, 0); @@ -1437,15 +1408,16 @@ retry: atomic_set(&cfqq->ref, 0); cfqq->cfqd = cfqd; - if (is_sync) { - cfq_mark_cfqq_idle_window(cfqq); - cfq_mark_cfqq_sync(cfqq); - } - cfq_mark_cfqq_prio_changed(cfqq); cfq_mark_cfqq_queue_new(cfqq); cfq_init_prio_data(cfqq, ioc); + + if (is_sync) { + if (!cfq_class_idle(cfqq)) + cfq_mark_cfqq_idle_window(cfqq); + cfq_mark_cfqq_sync(cfqq); + } } if (new_cfqq) @@ -1697,7 +1669,10 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, { int enable_idle; - if (!cfq_cfqq_sync(cfqq)) + /* + * Don't idle for async or idle io prio class + */ + if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) return; enable_idle = cfq_cfqq_idle_window(cfqq); @@ -1876,7 +1851,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) cfq_set_prio_slice(cfqd, cfqq); cfq_clear_cfqq_slice_new(cfqq); } - if (cfq_slice_used(cfqq)) + if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) cfq_slice_expired(cfqd, 1); else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) cfq_arm_slice_timer(cfqd); @@ -2080,29 +2055,9 @@ out_cont: spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); } -/* - * Timer running if an idle class queue is waiting for service - */ -static void cfq_idle_class_timer(unsigned long data) -{ - struct cfq_data *cfqd = (struct cfq_data *) data; - unsigned long flags; - - spin_lock_irqsave(cfqd->queue->queue_lock, flags); - - /* - * race with a non-idle queue, reset timer - */ - if (!start_idle_class_timer(cfqd)) - cfq_schedule_dispatch(cfqd); - - spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); -} - static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) { del_timer_sync(&cfqd->idle_slice_timer); - del_timer_sync(&cfqd->idle_class_timer); kblockd_flush_work(&cfqd->unplug_work); } @@ -2167,10 +2122,6 @@ static void *cfq_init_queue(struct request_queue *q) cfqd->idle_slice_timer.function = cfq_idle_slice_timer; cfqd->idle_slice_timer.data = (unsigned long) cfqd; - init_timer(&cfqd->idle_class_timer); - cfqd->idle_class_timer.function = cfq_idle_class_timer; - cfqd->idle_class_timer.data = (unsigned long) cfqd; - INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); cfqd->last_end_request = jiffies; |