X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=block%2Fcfq-iosched.c;h=0d3b70de3d80e7385d5fce32186819dc4f52e618;hb=6707bd3d420f53ae8f090dac871843f6f43c9980;hp=03a5953bb5df0cb16eb004bf8acb9bdbf3baad22;hpb=a68bbddba486020c9c74825ce90c4c1ec463e0e8;p=safe%2Fjmp%2Flinux-2.6 diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 03a5953..0d3b70d 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -56,9 +56,6 @@ static DEFINE_SPINLOCK(ioc_gone_lock); #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) -#define ASYNC (0) -#define SYNC (1) - #define sample_valid(samples) ((samples) > 80) /* @@ -83,7 +80,20 @@ struct cfq_data { * rr list of queues with requests and the count of them */ struct cfq_rb_root service_tree; + + /* + * Each priority tree is sorted by next_request position. These + * trees are used when determining if two or more queues are + * interleaving requests (see cfq_close_cooperator). + */ + struct rb_root prio_trees[CFQ_PRIO_LISTS]; + unsigned int busy_queues; + /* + * Used to track any pending rt requests so we can pre-empt current + * non-RT cfqq in service when this value is non-zero. + */ + unsigned int busy_rt_queues; int rq_in_driver; int sync_flight; @@ -142,6 +152,8 @@ struct cfq_queue { struct rb_node rb_node; /* service_tree key */ unsigned long rb_key; + /* prio tree member */ + struct rb_node p_node; /* sorted list of pending requests */ struct rb_root sort_list; /* if fifo isn't expired, next request to serve */ @@ -155,6 +167,7 @@ struct cfq_queue { unsigned long slice_end; long slice_resid; + unsigned int slice_dispatch; /* pending metadata requests */ int meta_pending; @@ -171,15 +184,15 @@ struct cfq_queue { enum cfqq_state_flags { CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ + CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */ CFQ_CFQQ_FLAG_must_alloc, /* must be allowed rq alloc */ CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ - CFQ_CFQQ_FLAG_must_dispatch, /* must dispatch, even if expired */ CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ - CFQ_CFQQ_FLAG_queue_new, /* queue never been serviced */ CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ CFQ_CFQQ_FLAG_sync, /* synchronous queue */ + CFQ_CFQQ_FLAG_coop, /* has done a coop jump of the queue */ }; #define CFQ_CFQQ_FNS(name) \ @@ -198,15 +211,15 @@ static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ CFQ_CFQQ_FNS(on_rr); CFQ_CFQQ_FNS(wait_request); +CFQ_CFQQ_FNS(must_dispatch); CFQ_CFQQ_FNS(must_alloc); CFQ_CFQQ_FNS(must_alloc_slice); -CFQ_CFQQ_FNS(must_dispatch); CFQ_CFQQ_FNS(fifo_expire); CFQ_CFQQ_FNS(idle_window); CFQ_CFQQ_FNS(prio_changed); -CFQ_CFQQ_FNS(queue_new); CFQ_CFQQ_FNS(slice_new); CFQ_CFQQ_FNS(sync); +CFQ_CFQQ_FNS(coop); #undef CFQ_CFQQ_FNS #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ @@ -415,13 +428,17 @@ static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) return NULL; } +static void rb_erase_init(struct rb_node *n, struct rb_root *root) +{ + rb_erase(n, root); + RB_CLEAR_NODE(n); +} + static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) { if (root->left == n) root->left = NULL; - - rb_erase(n, &root->rb); - RB_CLEAR_NODE(n); + rb_erase_init(n, &root->rb); } /* @@ -466,8 +483,8 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd, * requests waiting to be processed. It is sorted in the order that * we will service the queues. */ -static void cfq_service_tree_add(struct cfq_data *cfqd, - struct cfq_queue *cfqq, int add_front) +static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, + int add_front) { struct rb_node **p, *parent; struct cfq_queue *__cfqq; @@ -540,6 +557,63 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb); } +static struct cfq_queue * +cfq_prio_tree_lookup(struct cfq_data *cfqd, int ioprio, sector_t sector, + struct rb_node **ret_parent, struct rb_node ***rb_link) +{ + struct rb_root *root = &cfqd->prio_trees[ioprio]; + struct rb_node **p, *parent; + struct cfq_queue *cfqq = NULL; + + parent = NULL; + p = &root->rb_node; + while (*p) { + struct rb_node **n; + + parent = *p; + cfqq = rb_entry(parent, struct cfq_queue, p_node); + + /* + * Sort strictly based on sector. Smallest to the left, + * largest to the right. + */ + if (sector > cfqq->next_rq->sector) + n = &(*p)->rb_right; + else if (sector < cfqq->next_rq->sector) + n = &(*p)->rb_left; + else + break; + p = n; + } + + *ret_parent = parent; + if (rb_link) + *rb_link = p; + return NULL; +} + +static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) +{ + struct rb_root *root = &cfqd->prio_trees[cfqq->ioprio]; + struct rb_node **p, *parent; + struct cfq_queue *__cfqq; + + if (!RB_EMPTY_NODE(&cfqq->p_node)) + rb_erase_init(&cfqq->p_node, root); + + if (cfq_class_idle(cfqq)) + return; + if (!cfqq->next_rq) + return; + + __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->ioprio, cfqq->next_rq->sector, + &parent, &p); + BUG_ON(__cfqq); + + rb_link_node(&cfqq->p_node, parent, p); + rb_insert_color(&cfqq->p_node, root); +} + /* * Update cfqq's position in the service tree. */ @@ -548,8 +622,10 @@ static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) /* * Resorting requires the cfqq to be on the RR list already. */ - if (cfq_cfqq_on_rr(cfqq)) + if (cfq_cfqq_on_rr(cfqq)) { cfq_service_tree_add(cfqd, cfqq, 0); + cfq_prio_tree_add(cfqd, cfqq); + } } /* @@ -562,6 +638,8 @@ static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) BUG_ON(cfq_cfqq_on_rr(cfqq)); cfq_mark_cfqq_on_rr(cfqq); cfqd->busy_queues++; + if (cfq_class_rt(cfqq)) + cfqd->busy_rt_queues++; cfq_resort_rr_list(cfqd, cfqq); } @@ -578,9 +656,13 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) if (!RB_EMPTY_NODE(&cfqq->rb_node)) cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); + if (!RB_EMPTY_NODE(&cfqq->p_node)) + rb_erase_init(&cfqq->p_node, &cfqd->prio_trees[cfqq->ioprio]); BUG_ON(!cfqd->busy_queues); cfqd->busy_queues--; + if (cfq_class_rt(cfqq)) + cfqd->busy_rt_queues--; } /* @@ -605,7 +687,7 @@ static void cfq_add_rq_rb(struct request *rq) { struct cfq_queue *cfqq = RQ_CFQQ(rq); struct cfq_data *cfqd = cfqq->cfqd; - struct request *__alias; + struct request *__alias, *prev; cfqq->queued[rq_is_sync(rq)]++; @@ -622,7 +704,15 @@ static void cfq_add_rq_rb(struct request *rq) /* * check if this request is a better next-serve candidate */ + prev = cfqq->next_rq; cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq); + + /* + * adjust priority tree position, if ->next_rq changes + */ + if (prev != cfqq->next_rq) + cfq_prio_tree_add(cfqd, cfqq); + BUG_ON(!cfqq->next_rq); } @@ -765,10 +855,15 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd, if (cfqq) { cfq_log_cfqq(cfqd, cfqq, "set_active"); cfqq->slice_end = 0; + cfqq->slice_dispatch = 0; + + cfq_clear_cfqq_wait_request(cfqq); + cfq_clear_cfqq_must_dispatch(cfqq); cfq_clear_cfqq_must_alloc_slice(cfqq); cfq_clear_cfqq_fifo_expire(cfqq); cfq_mark_cfqq_slice_new(cfqq); - cfq_clear_cfqq_queue_new(cfqq); + + del_timer(&cfqd->idle_slice_timer); } cfqd->active_queue = cfqq; @@ -786,7 +881,6 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cfq_cfqq_wait_request(cfqq)) del_timer(&cfqd->idle_slice_timer); - cfq_clear_cfqq_must_dispatch(cfqq); cfq_clear_cfqq_wait_request(cfqq); /* @@ -831,11 +925,15 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) /* * Get and set a new active queue for service. */ -static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) +static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, + struct cfq_queue *cfqq) { - struct cfq_queue *cfqq; + if (!cfqq) { + cfqq = cfq_get_next_queue(cfqd); + if (cfqq) + cfq_clear_cfqq_coop(cfqq); + } - cfqq = cfq_get_next_queue(cfqd); __cfq_set_active_queue(cfqd, cfqq); return cfqq; } @@ -859,17 +957,89 @@ static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq) return cfq_dist_from_last(cfqd, rq) <= cic->seek_mean; } -static int cfq_close_cooperator(struct cfq_data *cfq_data, - struct cfq_queue *cfqq) +static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, + struct cfq_queue *cur_cfqq) { + struct rb_root *root = &cfqd->prio_trees[cur_cfqq->ioprio]; + struct rb_node *parent, *node; + struct cfq_queue *__cfqq; + sector_t sector = cfqd->last_position; + + if (RB_EMPTY_ROOT(root)) + return NULL; + + /* + * First, if we find a request starting at the end of the last + * request, choose it. + */ + __cfqq = cfq_prio_tree_lookup(cfqd, cur_cfqq->ioprio, + sector, &parent, NULL); + if (__cfqq) + return __cfqq; + + /* + * If the exact sector wasn't found, the parent of the NULL leaf + * will contain the closest sector. + */ + __cfqq = rb_entry(parent, struct cfq_queue, p_node); + if (cfq_rq_close(cfqd, __cfqq->next_rq)) + return __cfqq; + + if (__cfqq->next_rq->sector < sector) + node = rb_next(&__cfqq->p_node); + else + node = rb_prev(&__cfqq->p_node); + if (!node) + return NULL; + + __cfqq = rb_entry(node, struct cfq_queue, p_node); + if (cfq_rq_close(cfqd, __cfqq->next_rq)) + return __cfqq; + + return NULL; +} + +/* + * cfqd - obvious + * cur_cfqq - passed in so that we don't decide that the current queue is + * closely cooperating with itself. + * + * So, basically we're assuming that that cur_cfqq has dispatched at least + * one request, and that cfqd->last_position reflects a position on the disk + * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid + * assumption. + */ +static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, + struct cfq_queue *cur_cfqq, + int probe) +{ + struct cfq_queue *cfqq; + + /* + * A valid cfq_io_context is necessary to compare requests against + * the seek_mean of the current cfqq. + */ + if (!cfqd->active_cic) + return NULL; + /* * We should notice if some of the queues are cooperating, eg * working closely on the same area of the disk. In that case, * we can group them together and don't waste time idling. */ - return 0; + cfqq = cfqq_close(cfqd, cur_cfqq); + if (!cfqq) + return NULL; + + if (cfq_cfqq_coop(cfqq)) + return NULL; + + if (!probe) + cfq_mark_cfqq_coop(cfqq); + return cfqq; } + #define CIC_SEEKY(cic) ((cic)->seek_mean > (8 * 1024)) static void cfq_arm_slice_timer(struct cfq_data *cfqd) @@ -879,9 +1049,11 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) unsigned long sl; /* - * SSD device without seek penalty, disable idling + * SSD device without seek penalty, disable idling. But only do so + * for devices that support queuing, otherwise we still have a problem + * with sync vs async workloads. */ - if (blk_queue_nonrot(cfqd->queue)) + if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) return; WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); @@ -906,14 +1078,6 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) if (!cic || !atomic_read(&cic->ioc->nr_tasks)) return; - /* - * See if this prio level has a good candidate - */ - if (cfq_close_cooperator(cfqd, cfqq) && - (sample_valid(cic->ttime_samples) && cic->ttime_mean > 2)) - return; - - cfq_mark_cfqq_must_dispatch(cfqq); cfq_mark_cfqq_wait_request(cfqq); /* @@ -926,7 +1090,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT)); mod_timer(&cfqd->idle_slice_timer, jiffies + sl); - cfq_log(cfqd, "arm_idle: %lu", sl); + cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl); } /* @@ -990,7 +1154,7 @@ cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) */ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) { - struct cfq_queue *cfqq; + struct cfq_queue *cfqq, *new_cfqq = NULL; cfqq = cfqd->active_queue; if (!cfqq) @@ -999,10 +1163,24 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) /* * The active queue has run out of time, expire it and select new. */ - if (cfq_slice_used(cfqq)) + if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) goto expire; /* + * If we have a RT cfqq waiting, then we pre-empt the current non-rt + * cfqq. + */ + if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) { + /* + * We simulate this as cfqq timed out so that it gets to bank + * the remaining of its time slice. + */ + cfq_log_cfqq(cfqd, cfqq, "preempt"); + cfq_slice_expired(cfqd, 1); + goto new_queue; + } + + /* * The active queue has requests and isn't expired, allow it to * dispatch. */ @@ -1010,6 +1188,16 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) goto keep_queue; /* + * If another queue has a request waiting within our mean seek + * distance, let it run. The expire code will check for close + * cooperators and put the close queue at the front of the service + * tree. + */ + new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0); + if (new_cfqq) + goto expire; + + /* * 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. @@ -1023,64 +1211,11 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) expire: cfq_slice_expired(cfqd, 0); new_queue: - cfqq = cfq_set_active_queue(cfqd); + cfqq = cfq_set_active_queue(cfqd, new_cfqq); keep_queue: return cfqq; } -/* - * Dispatch some requests from cfqq, moving them to the request queue - * dispatch list. - */ -static int -__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, - int max_dispatch) -{ - int dispatched = 0; - - BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); - - do { - struct request *rq; - - /* - * follow expired path, else get first next available - */ - rq = cfq_check_fifo(cfqq); - if (rq == NULL) - rq = cfqq->next_rq; - - /* - * finally, insert request into driver dispatch list - */ - cfq_dispatch_insert(cfqd->queue, rq); - - dispatched++; - - if (!cfqd->active_cic) { - atomic_inc(&RQ_CIC(rq)->ioc->refcount); - cfqd->active_cic = RQ_CIC(rq); - } - - if (RB_EMPTY_ROOT(&cfqq->sort_list)) - break; - - } while (dispatched < max_dispatch); - - /* - * expire an async queue immediately if it has used up its slice. idle - * queue always expire after 1 dispatch round. - */ - if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && - dispatched >= cfq_prio_to_maxrq(cfqd, cfqq)) || - cfq_class_idle(cfqq))) { - cfqq->slice_end = jiffies + 1; - cfq_slice_expired(cfqd, 0); - } - - return dispatched; -} - static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) { int dispatched = 0; @@ -1114,11 +1249,45 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd) return dispatched; } +/* + * Dispatch a request from cfqq, moving them to the request queue + * dispatch list. + */ +static void cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) +{ + struct request *rq; + + BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); + + /* + * follow expired path, else get first next available + */ + rq = cfq_check_fifo(cfqq); + if (!rq) + rq = cfqq->next_rq; + + /* + * insert request into driver dispatch list + */ + cfq_dispatch_insert(cfqd->queue, rq); + + if (!cfqd->active_cic) { + struct cfq_io_context *cic = RQ_CIC(rq); + + atomic_inc(&cic->ioc->refcount); + cfqd->active_cic = cic; + } +} + +/* + * Find the cfqq that we need to service and move a request from that to the + * dispatch list + */ static int cfq_dispatch_requests(struct request_queue *q, int force) { struct cfq_data *cfqd = q->elevator->elevator_data; struct cfq_queue *cfqq; - int dispatched; + unsigned int max_dispatch; if (!cfqd->busy_queues) return 0; @@ -1126,33 +1295,63 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) if (unlikely(force)) return cfq_forced_dispatch(cfqd); - dispatched = 0; - while ((cfqq = cfq_select_queue(cfqd)) != NULL) { - int max_dispatch; + cfqq = cfq_select_queue(cfqd); + if (!cfqq) + 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)) + return 0; + + max_dispatch = cfqd->cfq_quantum; + if (cfq_class_idle(cfqq)) + max_dispatch = 1; - max_dispatch = cfqd->cfq_quantum; + /* + * Does this cfqq already have too much IO in flight? + */ + if (cfqq->dispatched >= max_dispatch) { + /* + * idle queue must always only have a single IO in flight + */ if (cfq_class_idle(cfqq)) - max_dispatch = 1; + return 0; - if (cfqq->dispatched >= max_dispatch) { - if (cfqd->busy_queues > 1) - break; - if (cfqq->dispatched >= 4 * max_dispatch) - break; - } + /* + * We have other queues, don't allow more IO from this one + */ + if (cfqd->busy_queues > 1) + return 0; - if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq)) - break; + /* + * we are the only queue, allow up to 4 times of 'quantum' + */ + if (cfqq->dispatched >= 4 * max_dispatch) + return 0; + } - cfq_clear_cfqq_must_dispatch(cfqq); - cfq_clear_cfqq_wait_request(cfqq); - del_timer(&cfqd->idle_slice_timer); + /* + * Dispatch a request from this cfqq + */ + cfq_dispatch_request(cfqd, cfqq); + cfqq->slice_dispatch++; + cfq_clear_cfqq_must_dispatch(cfqq); - dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); + /* + * expire an async queue immediately if it has used up its slice. idle + * queue always expire after 1 dispatch round. + */ + if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && + cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || + cfq_class_idle(cfqq))) { + cfqq->slice_end = jiffies + 1; + cfq_slice_expired(cfqd, 0); } - cfq_log(cfqd, "dispatched=%d", dispatched); - return dispatched; + cfq_log(cfqd, "dispatched a request"); + return 1; } /* @@ -1295,14 +1494,14 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd, if (ioc->ioc_data == cic) rcu_assign_pointer(ioc->ioc_data, NULL); - if (cic->cfqq[ASYNC]) { - cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]); - cic->cfqq[ASYNC] = NULL; + if (cic->cfqq[BLK_RW_ASYNC]) { + cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); + cic->cfqq[BLK_RW_ASYNC] = NULL; } - if (cic->cfqq[SYNC]) { - cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]); - cic->cfqq[SYNC] = NULL; + if (cic->cfqq[BLK_RW_SYNC]) { + cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); + cic->cfqq[BLK_RW_SYNC] = NULL; } } @@ -1316,7 +1515,15 @@ static void cfq_exit_single_io_context(struct io_context *ioc, unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); - __cfq_exit_single_io_context(cfqd, cic); + + /* + * Ensure we get a fresh copy of the ->key to prevent + * race between exiting task and queue + */ + smp_read_barrier_depends(); + if (cic->key) + __cfq_exit_single_io_context(cfqd, cic); + spin_unlock_irqrestore(q->queue_lock, flags); } } @@ -1403,17 +1610,18 @@ static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) spin_lock_irqsave(cfqd->queue->queue_lock, flags); - cfqq = cic->cfqq[ASYNC]; + cfqq = cic->cfqq[BLK_RW_ASYNC]; if (cfqq) { struct cfq_queue *new_cfqq; - new_cfqq = cfq_get_queue(cfqd, ASYNC, cic->ioc, GFP_ATOMIC); + new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc, + GFP_ATOMIC); if (new_cfqq) { - cic->cfqq[ASYNC] = new_cfqq; + cic->cfqq[BLK_RW_ASYNC] = new_cfqq; cfq_put_queue(cfqq); } } - cfqq = cic->cfqq[SYNC]; + cfqq = cic->cfqq[BLK_RW_SYNC]; if (cfqq) cfq_mark_cfqq_prio_changed(cfqq); @@ -1464,13 +1672,13 @@ retry: } RB_CLEAR_NODE(&cfqq->rb_node); + RB_CLEAR_NODE(&cfqq->p_node); INIT_LIST_HEAD(&cfqq->fifo); atomic_set(&cfqq->ref, 0); cfqq->cfqd = cfqd; cfq_mark_cfqq_prio_changed(cfqq); - cfq_mark_cfqq_queue_new(cfqq); cfq_init_prio_data(cfqq, ioc); @@ -1795,6 +2003,12 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, if (rq_is_meta(rq) && !cfqq->meta_pending) return 1; + /* + * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. + */ + if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) + return 1; + if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) return 0; @@ -1851,23 +2065,31 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cfqq == cfqd->active_queue) { /* - * if we are waiting for a request for this queue, let it rip - * immediately and flag that we must not expire this queue - * just now + * Remember that we saw a request from this process, but + * don't start queuing just yet. Otherwise we risk seeing lots + * of tiny requests, because we disrupt the normal plugging + * and merging. If the request is already larger than a single + * page, let it rip immediately. For that case we assume that + * merging is already done. Ditto for a busy system that + * has other work pending, don't risk delaying until the + * idle timer unplug to continue working. */ if (cfq_cfqq_wait_request(cfqq)) { + if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || + cfqd->busy_queues > 1) { + del_timer(&cfqd->idle_slice_timer); + blk_start_queueing(cfqd->queue); + } cfq_mark_cfqq_must_dispatch(cfqq); - del_timer(&cfqd->idle_slice_timer); - blk_start_queueing(cfqd->queue); } } else if (cfq_should_preempt(cfqd, cfqq, rq)) { /* * not the active queue - expire current slice if it is * idle and has expired it's mean thinktime or this new queue - * has some old slice time left and is of higher priority + * has some old slice time left and is of higher priority or + * this new queue is RT and the current one is BE */ cfq_preempt_queue(cfqd, cfqq); - cfq_mark_cfqq_must_dispatch(cfqq); blk_start_queueing(cfqd->queue); } } @@ -1943,13 +2165,23 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) * or if we want to idle in case it has no pending requests. */ if (cfqd->active_queue == cfqq) { + const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); + if (cfq_cfqq_slice_new(cfqq)) { cfq_set_prio_slice(cfqd, cfqq); cfq_clear_cfqq_slice_new(cfqq); } + /* + * If there are no requests waiting in this queue, and + * there are other queues ready to issue requests, AND + * those other queues are issuing requests within our + * mean seek distance, give them a chance to run instead + * of idling. + */ if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) cfq_slice_expired(cfqd, 1); - else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) + else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq, 1) && + sync && !rq_noidle(rq)) cfq_arm_slice_timer(cfqd); } @@ -2011,7 +2243,7 @@ static int cfq_may_queue(struct request_queue *q, int rw) if (!cic) return ELV_MQUEUE_MAY; - cfqq = cic_to_cfqq(cic, rw & REQ_RW_SYNC); + cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); if (cfqq) { cfq_init_prio_data(cfqq, cic->ioc); cfq_prio_boost(cfqq); @@ -2101,11 +2333,10 @@ static void cfq_kick_queue(struct work_struct *work) struct cfq_data *cfqd = container_of(work, struct cfq_data, unplug_work); struct request_queue *q = cfqd->queue; - unsigned long flags; - spin_lock_irqsave(q->queue_lock, flags); + spin_lock_irq(q->queue_lock); blk_start_queueing(q); - spin_unlock_irqrestore(q->queue_lock, flags); + spin_unlock_irq(q->queue_lock); } /* @@ -2127,6 +2358,12 @@ static void cfq_idle_slice_timer(unsigned long data) timed_out = 0; /* + * We saw a request before the queue expired, let it through + */ + if (cfq_cfqq_must_dispatch(cfqq)) + goto out_kick; + + /* * expired */ if (cfq_slice_used(cfqq)) @@ -2142,10 +2379,8 @@ static void cfq_idle_slice_timer(unsigned long data) /* * not expired and it has a request pending, let it dispatch */ - if (!RB_EMPTY_ROOT(&cfqq->sort_list)) { - cfq_mark_cfqq_must_dispatch(cfqq); + if (!RB_EMPTY_ROOT(&cfqq->sort_list)) goto out_kick; - } } expire: cfq_slice_expired(cfqd, timed_out); @@ -2158,7 +2393,7 @@ out_cont: static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) { del_timer_sync(&cfqd->idle_slice_timer); - kblockd_flush_work(&cfqd->unplug_work); + cancel_work_sync(&cfqd->unplug_work); } static void cfq_put_async_queues(struct cfq_data *cfqd) @@ -2176,7 +2411,7 @@ static void cfq_put_async_queues(struct cfq_data *cfqd) cfq_put_queue(cfqd->async_idle_cfqq); } -static void cfq_exit_queue(elevator_t *e) +static void cfq_exit_queue(struct elevator_queue *e) { struct cfq_data *cfqd = e->elevator_data; struct request_queue *q = cfqd->queue; @@ -2286,7 +2521,7 @@ cfq_var_store(unsigned int *var, const char *page, size_t count) } #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ -static ssize_t __FUNC(elevator_t *e, char *page) \ +static ssize_t __FUNC(struct elevator_queue *e, char *page) \ { \ struct cfq_data *cfqd = e->elevator_data; \ unsigned int __data = __VAR; \ @@ -2306,7 +2541,7 @@ SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); #undef SHOW_FUNCTION #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ -static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ +static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ { \ struct cfq_data *cfqd = e->elevator_data; \ unsigned int __data; \