X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=block%2Fcfq-iosched.c;h=023f4e69a3378cab44faefbf6c69823e6ec16b48;hb=a49c65037146bfb2fe300b8277b10b4479fea5fc;hp=a877eeee80af7e82a09e3c3d0c1d75220b2b0f44;hpb=25fb5169d4c9d4255107abbb7c08ab712434efc8;p=safe%2Fjmp%2Flinux-2.6 diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index a877eee..023f4e6 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -42,16 +42,13 @@ static const int cfq_hist_divisor = 4; */ #define CFQ_MIN_TT (2) -/* - * Allow merged cfqqs to perform this amount of seeky I/O before - * deciding to break the queues up again. - */ -#define CFQQ_COOP_TOUT (HZ) - #define CFQ_SLICE_SCALE (5) #define CFQ_HW_QUEUE_MIN (5) #define CFQ_SERVICE_SHIFT 12 +#define CFQQ_SEEK_THR 8 * 1024 +#define CFQQ_SEEKY(cfqq) ((cfqq)->seek_mean > CFQQ_SEEK_THR) + #define RQ_CIC(rq) \ ((struct cfq_io_context *) (rq)->elevator_private) #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2) @@ -117,6 +114,7 @@ struct cfq_queue { /* time when queue got scheduled in to dispatch first request. */ unsigned long dispatch_start; + unsigned int allocated_slice; /* time when first request from queue completed and slice started. */ unsigned long slice_start; unsigned long slice_end; @@ -136,13 +134,15 @@ struct cfq_queue { u64 seek_total; sector_t seek_mean; sector_t last_request_pos; - unsigned long seeky_start; pid_t pid; struct cfq_rb_root *service_tree; struct cfq_queue *new_cfqq; struct cfq_group *cfqg; + struct cfq_group *orig_cfqg; + /* Sectors dispatched in current dispatch round */ + unsigned long nr_sectors; }; /* @@ -192,6 +192,7 @@ struct cfq_group { struct blkio_group blkg; #ifdef CONFIG_CFQ_GROUP_IOSCHED struct hlist_node cfqd_node; + atomic_t ref; #endif }; @@ -203,8 +204,6 @@ struct cfq_data { /* Root service tree for cfq_groups */ struct cfq_rb_root grp_service_tree; struct cfq_group root_group; - /* Number of active cfq groups on group service tree */ - int nr_groups; /* * The priority currently being served @@ -269,6 +268,7 @@ struct cfq_data { unsigned int cfq_slice_async_rq; unsigned int cfq_slice_idle; unsigned int cfq_latency; + unsigned int cfq_group_isolation; struct list_head cic_list; @@ -277,18 +277,18 @@ struct cfq_data { */ struct cfq_queue oom_cfqq; - unsigned long last_end_sync_rq; + unsigned long last_delayed_sync; /* List of cfq groups being managed on this device*/ struct hlist_head cfqg_list; + struct rcu_head rcu; }; static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, enum wl_prio_t prio, - enum wl_type_t type, - struct cfq_data *cfqd) + enum wl_type_t type) { if (!cfqg) return NULL; @@ -310,7 +310,9 @@ enum cfqq_state_flags { CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ CFQ_CFQQ_FLAG_sync, /* synchronous queue */ CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ + CFQ_CFQQ_FLAG_split_coop, /* shared cfqq will be splitted */ CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ + CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ }; #define CFQ_CFQQ_FNS(name) \ @@ -337,11 +339,26 @@ CFQ_CFQQ_FNS(prio_changed); CFQ_CFQQ_FNS(slice_new); CFQ_CFQQ_FNS(sync); CFQ_CFQQ_FNS(coop); +CFQ_CFQQ_FNS(split_coop); CFQ_CFQQ_FNS(deep); +CFQ_CFQQ_FNS(wait_busy); #undef CFQ_CFQQ_FNS +#ifdef CONFIG_DEBUG_CFQ_IOSCHED +#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ + blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \ + cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \ + blkg_path(&(cfqq)->cfqg->blkg), ##args); + +#define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \ + blk_add_trace_msg((cfqd)->queue, "%s " fmt, \ + blkg_path(&(cfqg)->blkg), ##args); \ + +#else #define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) +#define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0); +#endif #define cfq_log(cfqd, fmt, args...) \ blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) @@ -387,6 +404,13 @@ static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, + cfqg->service_trees[wl][SYNC_WORKLOAD].count; } +static inline int cfqg_busy_async_queues(struct cfq_data *cfqd, + struct cfq_group *cfqg) +{ + return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count + + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count; +} + static void cfq_dispatch_insert(struct request_queue *, struct request *); static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, struct io_context *, gfp_t); @@ -562,6 +586,7 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) } cfqq->slice_start = jiffies; cfqq->slice_end = jiffies + slice; + cfqq->allocated_slice = slice; cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); } @@ -812,7 +837,6 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg) __cfq_group_service_tree_add(st, cfqg); cfqg->on_st = true; - cfqd->nr_groups++; st->total_weight += cfqg->weight; } @@ -831,17 +855,18 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg) if (cfqg->nr_cfqq) return; + cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); cfqg->on_st = false; - cfqd->nr_groups--; st->total_weight -= cfqg->weight; if (!RB_EMPTY_NODE(&cfqg->rb_node)) cfq_rb_erase(&cfqg->rb_node, st); cfqg->saved_workload_slice = 0; + blkiocg_update_blkio_group_dequeue_stats(&cfqg->blkg, 1); } static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq) { - unsigned int slice_used, allocated_slice; + unsigned int slice_used; /* * Queue got expired before even a single request completed or @@ -858,12 +883,12 @@ static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq) 1); } else { slice_used = jiffies - cfqq->slice_start; - allocated_slice = cfqq->slice_end - cfqq->slice_start; - if (slice_used > allocated_slice) - slice_used = allocated_slice; + if (slice_used > cfqq->allocated_slice) + slice_used = cfqq->allocated_slice; } - cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u", slice_used); + cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u sect=%lu", slice_used, + cfqq->nr_sectors); return slice_used; } @@ -871,13 +896,19 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, struct cfq_queue *cfqq) { struct cfq_rb_root *st = &cfqd->grp_service_tree; - unsigned int used_sl; + unsigned int used_sl, charge_sl; + int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg) + - cfqg->service_tree_idle.count; + + BUG_ON(nr_sync < 0); + used_sl = charge_sl = cfq_cfqq_slice_usage(cfqq); - used_sl = cfq_cfqq_slice_usage(cfqq); + if (!cfq_cfqq_sync(cfqq) && !nr_sync) + charge_sl = cfqq->allocated_slice; /* Can't update vdisktime while group is on service tree */ cfq_rb_erase(&cfqg->rb_node, st); - cfqg->vdisktime += cfq_scale_slice(used_sl, cfqg); + cfqg->vdisktime += cfq_scale_slice(charge_sl, cfqg); __cfq_group_service_tree_add(st, cfqg); /* This group is being expired. Save the context */ @@ -888,6 +919,11 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, cfqg->saved_serving_prio = cfqd->serving_prio; } else cfqg->saved_workload_slice = 0; + + cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime, + st->min_vdisktime); + blkiocg_update_blkio_group_stats(&cfqg->blkg, used_sl, + cfqq->nr_sectors); } #ifdef CONFIG_CFQ_GROUP_IOSCHED @@ -898,6 +934,12 @@ static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) return NULL; } +void +cfq_update_blkio_group_weight(struct blkio_group *blkg, unsigned int weight) +{ + cfqg_of_blkg(blkg)->weight = weight; +} + static struct cfq_group * cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) { @@ -906,9 +948,11 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) void *key = cfqd; int i, j; struct cfq_rb_root *st; + struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; + unsigned int major, minor; /* Do we need to take this reference */ - if (!css_tryget(&blkcg->css)) + if (!blkiocg_css_tryget(blkcg)) return NULL;; cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); @@ -924,14 +968,24 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) *st = CFQ_RB_ROOT; RB_CLEAR_NODE(&cfqg->rb_node); + /* + * Take the initial reference that will be released on destroy + * This can be thought of a joint reference by cgroup and + * elevator which will be dropped by either elevator exit + * or cgroup deletion path depending on who is exiting first. + */ + atomic_set(&cfqg->ref, 1); + /* Add group onto cgroup list */ - blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd); + sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); + blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd, + MKDEV(major, minor)); /* Add group on cfqd list */ hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); done: - css_put(&blkcg->css); + blkiocg_css_put(blkcg); return cfqg; } @@ -960,7 +1014,77 @@ static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) cfqg = &cfqq->cfqd->root_group; cfqq->cfqg = cfqg; + /* cfqq reference on cfqg */ + atomic_inc(&cfqq->cfqg->ref); +} + +static void cfq_put_cfqg(struct cfq_group *cfqg) +{ + struct cfq_rb_root *st; + int i, j; + + BUG_ON(atomic_read(&cfqg->ref) <= 0); + if (!atomic_dec_and_test(&cfqg->ref)) + return; + for_each_cfqg_st(cfqg, i, j, st) + BUG_ON(!RB_EMPTY_ROOT(&st->rb) || st->active != NULL); + kfree(cfqg); +} + +static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) +{ + /* Something wrong if we are trying to remove same group twice */ + BUG_ON(hlist_unhashed(&cfqg->cfqd_node)); + + hlist_del_init(&cfqg->cfqd_node); + + /* + * Put the reference taken at the time of creation so that when all + * queues are gone, group can be destroyed. + */ + cfq_put_cfqg(cfqg); +} + +static void cfq_release_cfq_groups(struct cfq_data *cfqd) +{ + struct hlist_node *pos, *n; + struct cfq_group *cfqg; + + hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) { + /* + * If cgroup removal path got to blk_group first and removed + * it from cgroup list, then it will take care of destroying + * cfqg also. + */ + if (!blkiocg_del_blkio_group(&cfqg->blkg)) + cfq_destroy_cfqg(cfqd, cfqg); + } +} + +/* + * Blk cgroup controller notification saying that blkio_group object is being + * delinked as associated cgroup object is going away. That also means that + * no new IO will come in this group. So get rid of this group as soon as + * any pending IO in the group is finished. + * + * This function is called under rcu_read_lock(). key is the rcu protected + * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu + * read lock. + * + * "key" was fetched from blkio_group under blkio_cgroup->lock. That means + * it should not be NULL as even if elevator was exiting, cgroup deltion + * path got to it first. + */ +void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg) +{ + unsigned long flags; + struct cfq_data *cfqd = key; + + spin_lock_irqsave(cfqd->queue->queue_lock, flags); + cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg)); + spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); } + #else /* GROUP_IOSCHED */ static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) { @@ -971,6 +1095,9 @@ cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) { cfqq->cfqg = cfqg; } +static void cfq_release_cfq_groups(struct cfq_data *cfqd) {} +static inline void cfq_put_cfqg(struct cfq_group *cfqg) {} + #endif /* GROUP_IOSCHED */ /* @@ -987,9 +1114,36 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, struct cfq_rb_root *service_tree; int left; int new_cfqq = 1; + int group_changed = 0; + +#ifdef CONFIG_CFQ_GROUP_IOSCHED + if (!cfqd->cfq_group_isolation + && cfqq_type(cfqq) == SYNC_NOIDLE_WORKLOAD + && cfqq->cfqg && cfqq->cfqg != &cfqd->root_group) { + /* Move this cfq to root group */ + cfq_log_cfqq(cfqd, cfqq, "moving to root group"); + if (!RB_EMPTY_NODE(&cfqq->rb_node)) + cfq_group_service_tree_del(cfqd, cfqq->cfqg); + cfqq->orig_cfqg = cfqq->cfqg; + cfqq->cfqg = &cfqd->root_group; + atomic_inc(&cfqd->root_group.ref); + group_changed = 1; + } else if (!cfqd->cfq_group_isolation + && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) { + /* cfqq is sequential now needs to go to its original group */ + BUG_ON(cfqq->cfqg != &cfqd->root_group); + if (!RB_EMPTY_NODE(&cfqq->rb_node)) + cfq_group_service_tree_del(cfqd, cfqq->cfqg); + cfq_put_cfqg(cfqq->cfqg); + cfqq->cfqg = cfqq->orig_cfqg; + cfqq->orig_cfqg = NULL; + group_changed = 1; + cfq_log_cfqq(cfqd, cfqq, "moved to origin group"); + } +#endif service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq), - cfqq_type(cfqq), cfqd); + cfqq_type(cfqq)); if (cfq_class_idle(cfqq)) { rb_key = CFQ_IDLE_DELAY; parent = rb_last(&service_tree->rb); @@ -1057,7 +1211,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, rb_link_node(&cfqq->rb_node, parent, p); rb_insert_color(&cfqq->rb_node, &service_tree->rb); service_tree->count++; - if (add_front || !new_cfqq) + if ((add_front || !new_cfqq) && !group_changed) return; cfq_group_service_tree_add(cfqd, cfqq->cfqg); } @@ -1377,8 +1531,10 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd, cfq_log_cfqq(cfqd, cfqq, "set_active"); cfqq->slice_start = 0; cfqq->dispatch_start = jiffies; + cfqq->allocated_slice = 0; cfqq->slice_end = 0; cfqq->slice_dispatch = 0; + cfqq->nr_sectors = 0; cfq_clear_cfqq_wait_request(cfqq); cfq_clear_cfqq_must_dispatch(cfqq); @@ -1405,6 +1561,16 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, del_timer(&cfqd->idle_slice_timer); cfq_clear_cfqq_wait_request(cfqq); + cfq_clear_cfqq_wait_busy(cfqq); + + /* + * If this cfqq is shared between multiple processes, check to + * make sure that those processes are still issuing I/Os within + * the mean seek distance. If not, it may be time to break the + * queues apart again. + */ + if (cfq_cfqq_coop(cfqq) && CFQQ_SEEKY(cfqq)) + cfq_mark_cfqq_split_coop(cfqq); /* * store what was left of this slice, if the queue idled/timed out @@ -1449,7 +1615,7 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) { struct cfq_rb_root *service_tree = service_tree_for(cfqd->serving_group, cfqd->serving_prio, - cfqd->serving_type, cfqd); + cfqd->serving_type); if (!cfqd->rq_queued) return NULL; @@ -1504,17 +1670,18 @@ static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, return cfqd->last_position - blk_rq_pos(rq); } -#define CFQQ_SEEK_THR 8 * 1024 -#define CFQQ_SEEKY(cfqq) ((cfqq)->seek_mean > CFQQ_SEEK_THR) - static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct request *rq) + struct request *rq, bool for_preempt) { sector_t sdist = cfqq->seek_mean; if (!sample_valid(cfqq->seek_samples)) sdist = CFQQ_SEEK_THR; + /* if seek_mean is big, using it as close criteria is meaningless */ + if (sdist > CFQQ_SEEK_THR && !for_preempt) + sdist = CFQQ_SEEK_THR; + return cfq_dist_from_last(cfqd, rq) <= sdist; } @@ -1542,7 +1709,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, * will contain the closest sector. */ __cfqq = rb_entry(parent, struct cfq_queue, p_node); - if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) + if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false)) return __cfqq; if (blk_rq_pos(__cfqq->next_rq) < sector) @@ -1553,7 +1720,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, return NULL; __cfqq = rb_entry(node, struct cfq_queue, p_node); - if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) + if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false)) return __cfqq; return NULL; @@ -1580,6 +1747,12 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, return NULL; /* + * Don't search priority tree if it's the only queue in the group. + */ + if (cur_cfqq->cfqg->nr_cfqq == 1) + 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. @@ -1588,6 +1761,10 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, if (!cfqq) return NULL; + /* If new queue belongs to different cfq_group, don't choose it */ + if (cur_cfqq->cfqg != cfqq->cfqg) + return NULL; + /* * It only makes sense to merge sync queues. */ @@ -1622,14 +1799,15 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) return false; /* We do for queues that were marked with idle window flag. */ - if (cfq_cfqq_idle_window(cfqq)) + if (cfq_cfqq_idle_window(cfqq) && + !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)) return true; /* * Otherwise, we do only if they are the last ones * in their service tree. */ - return service_tree->count == 1; + return service_tree->count == 1 && cfq_cfqq_sync(cfqq); } static void cfq_arm_slice_timer(struct cfq_data *cfqd) @@ -1702,6 +1880,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) if (cfq_cfqq_sync(cfqq)) cfqd->sync_flight++; + cfqq->nr_sectors += blk_rq_sectors(rq); } /* @@ -1784,8 +1963,7 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) } static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, - struct cfq_group *cfqg, enum wl_prio_t prio, - bool prio_changed) + struct cfq_group *cfqg, enum wl_prio_t prio) { struct cfq_queue *queue; int i; @@ -1793,24 +1971,9 @@ static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, unsigned long lowest_key = 0; enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; - if (prio_changed) { - /* - * When priorities switched, we prefer starting - * from SYNC_NOIDLE (first choice), or just SYNC - * over ASYNC - */ - if (service_tree_for(cfqg, prio, cur_best, cfqd)->count) - return cur_best; - cur_best = SYNC_WORKLOAD; - if (service_tree_for(cfqg, prio, cur_best, cfqd)->count) - return cur_best; - - return ASYNC_WORKLOAD; - } - - for (i = 0; i < 3; ++i) { - /* otherwise, select the one with lowest rb_key */ - queue = cfq_rb_first(service_tree_for(cfqg, prio, i, cfqd)); + for (i = 0; i <= SYNC_WORKLOAD; ++i) { + /* select the one with lowest rb_key */ + queue = cfq_rb_first(service_tree_for(cfqg, prio, i)); if (queue && (!key_valid || time_before(queue->rb_key, lowest_key))) { lowest_key = queue->rb_key; @@ -1824,8 +1987,6 @@ static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) { - enum wl_prio_t previous_prio = cfqd->serving_prio; - bool prio_changed; unsigned slice; unsigned count; struct cfq_rb_root *st; @@ -1853,24 +2014,19 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload * expiration time */ - prio_changed = (cfqd->serving_prio != previous_prio); - st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type, - cfqd); + st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); count = st->count; /* - * If priority didn't change, check workload expiration, - * and that we still have other queues ready + * check workload expiration, and that we still have other queues ready */ - if (!prio_changed && count && - !time_after(jiffies, cfqd->workload_expires)) + if (count && !time_after(jiffies, cfqd->workload_expires)) return; /* otherwise select new workload type */ cfqd->serving_type = - cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio, prio_changed); - st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type, - cfqd); + cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio); + st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); count = st->count; /* @@ -1884,11 +2040,24 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); - if (cfqd->serving_type == ASYNC_WORKLOAD) + if (cfqd->serving_type == ASYNC_WORKLOAD) { + unsigned int tmp; + + /* + * Async queues are currently system wide. Just taking + * proportion of queues with-in same group will lead to higher + * async ratio system wide as generally root group is going + * to have higher weight. A more accurate thing would be to + * calculate system wide asnc/sync ratio. + */ + tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg); + tmp = tmp/cfqd->busy_queues; + slice = min_t(unsigned, slice, tmp); + /* async workload slice is scaled down according to * the sync/async slice ratio. */ slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1]; - else + } else /* sync workload slice is at least 2 * cfq_slice_idle */ slice = max(slice, 2 * cfqd->cfq_slice_idle); @@ -1921,7 +2090,9 @@ static void cfq_choose_cfqg(struct cfq_data *cfqd) cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; cfqd->serving_type = cfqg->saved_workload; cfqd->serving_prio = cfqg->saved_serving_prio; - } + } else + cfqd->workload_expires = jiffies - 1; + choose_service_tree(cfqd, cfqg); } @@ -1939,13 +2110,35 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) if (!cfqd->rq_queued) return NULL; + /* - * The active queue has run out of time, expire it and select new. + * We were waiting for group to get backlogged. Expire the queue */ - if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) + if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list)) goto expire; /* + * The active queue has run out of time, expire it and select new. + */ + if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { + /* + * If slice had not expired at the completion of last request + * we might not have turned on wait_busy flag. Don't expire + * the queue yet. Allow the group to get backlogged. + * + * The very fact that we have used the slice, that means we + * have been idling all along on this queue and it should be + * ok to wait for this request to complete. + */ + if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list) + && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { + cfqq = NULL; + goto keep_queue; + } else + goto expire; + } + + /* * The active queue has requests and isn't expired, allow it to * dispatch. */ @@ -2074,7 +2267,7 @@ static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) * based on the last sync IO we serviced */ if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { - unsigned long last_sync = jiffies - cfqd->last_end_sync_rq; + unsigned long last_sync = jiffies - cfqd->last_delayed_sync; unsigned int depth; depth = last_sync / cfqd->cfq_slice[1]; @@ -2172,11 +2365,13 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) * task holds one reference to the queue, dropped when task exits. each rq * in-flight on this queue also holds a reference, dropped when rq is freed. * + * Each cfq queue took a reference on the parent group. Drop it now. * queue lock must be held here. */ static void cfq_put_queue(struct cfq_queue *cfqq) { struct cfq_data *cfqd = cfqq->cfqd; + struct cfq_group *cfqg, *orig_cfqg; BUG_ON(atomic_read(&cfqq->ref) <= 0); @@ -2186,6 +2381,8 @@ static void cfq_put_queue(struct cfq_queue *cfqq) cfq_log_cfqq(cfqd, cfqq, "put_queue"); BUG_ON(rb_first(&cfqq->sort_list)); BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); + cfqg = cfqq->cfqg; + orig_cfqg = cfqq->orig_cfqg; if (unlikely(cfqd->active_queue == cfqq)) { __cfq_slice_expired(cfqd, cfqq, 0); @@ -2194,6 +2391,9 @@ static void cfq_put_queue(struct cfq_queue *cfqq) BUG_ON(cfq_cfqq_on_rr(cfqq)); kmem_cache_free(cfq_pool, cfqq); + cfq_put_cfqg(cfqg); + if (orig_cfqg) + cfq_put_cfqg(orig_cfqg); } /* @@ -2486,6 +2686,41 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, cfqq->pid = pid; } +#ifdef CONFIG_CFQ_GROUP_IOSCHED +static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic) +{ + struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); + struct cfq_data *cfqd = cic->key; + unsigned long flags; + struct request_queue *q; + + if (unlikely(!cfqd)) + return; + + q = cfqd->queue; + + spin_lock_irqsave(q->queue_lock, flags); + + if (sync_cfqq) { + /* + * Drop reference to sync queue. A new sync queue will be + * assigned in new group upon arrival of a fresh request. + */ + cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup"); + cic_set_cfqq(cic, NULL, 1); + cfq_put_queue(sync_cfqq); + } + + spin_unlock_irqrestore(q->queue_lock, flags); +} + +static void cfq_ioc_set_cgroup(struct io_context *ioc) +{ + call_for_each_cic(ioc, changed_cgroup); + ioc->cgroup_changed = 0; +} +#endif /* CONFIG_CFQ_GROUP_IOSCHED */ + static struct cfq_queue * cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, gfp_t gfp_mask) @@ -2718,6 +2953,10 @@ out: if (unlikely(ioc->ioprio_changed)) cfq_ioc_set_ioprio(ioc); +#ifdef CONFIG_CFQ_GROUP_IOSCHED + if (unlikely(ioc->cgroup_changed)) + cfq_ioc_set_cgroup(ioc); +#endif return cic; err_free: cfq_cic_free(cic); @@ -2765,19 +3004,6 @@ cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, total = cfqq->seek_total + (cfqq->seek_samples/2); do_div(total, cfqq->seek_samples); cfqq->seek_mean = (sector_t)total; - - /* - * If this cfqq is shared between multiple processes, check to - * make sure that those processes are still issuing I/Os within - * the mean seek distance. If not, it may be time to break the - * queues apart again. - */ - if (cfq_cfqq_coop(cfqq)) { - if (CFQQ_SEEKY(cfqq) && !cfqq->seeky_start) - cfqq->seeky_start = jiffies; - else if (!CFQQ_SEEKY(cfqq)) - cfqq->seeky_start = 0; - } } /* @@ -2835,21 +3061,17 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, if (!cfqq) return false; - if (cfq_slice_used(cfqq)) - return true; - if (cfq_class_idle(new_cfqq)) return false; if (cfq_class_idle(cfqq)) return true; - /* Allow preemption only if we are idling on sync-noidle tree */ - if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && - cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && - new_cfqq->service_tree->count == 2 && - RB_EMPTY_ROOT(&cfqq->sort_list)) - return true; + /* + * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice. + */ + if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq)) + return false; /* * if the new request is sync, but the currently running queue is @@ -2858,6 +3080,19 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) return true; + if (new_cfqq->cfqg != cfqq->cfqg) + return false; + + if (cfq_slice_used(cfqq)) + return true; + + /* Allow preemption only if we are idling on sync-noidle tree */ + if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && + cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && + new_cfqq->service_tree->count == 2 && + RB_EMPTY_ROOT(&cfqq->sort_list)) + return true; + /* * So both queues are sync. Let the new request get disk time if * it's a metadata request and the current queue is doing regular IO. @@ -2878,7 +3113,7 @@ 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 * current cfqq, let it preempt */ - if (cfq_rq_close(cfqd, cfqq, rq)) + if (cfq_rq_close(cfqd, cfqq, rq, true)) return true; return false; @@ -2940,6 +3175,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || cfqd->busy_queues > 1) { del_timer(&cfqd->idle_slice_timer); + cfq_clear_cfqq_wait_request(cfqq); __blk_run_queue(cfqd->queue); } else cfq_mark_cfqq_must_dispatch(cfqq); @@ -3008,6 +3244,35 @@ static void cfq_update_hw_tag(struct cfq_data *cfqd) cfqd->hw_tag = 0; } +static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq) +{ + struct cfq_io_context *cic = cfqd->active_cic; + + /* If there are other queues in the group, don't wait */ + if (cfqq->cfqg->nr_cfqq > 1) + return false; + + if (cfq_slice_used(cfqq)) + return true; + + /* if slice left is less than think time, wait busy */ + if (cic && sample_valid(cic->ttime_samples) + && (cfqq->slice_end - jiffies < cic->ttime_mean)) + return true; + + /* + * If think times is less than a jiffy than ttime_mean=0 and above + * will not be true. It might happen that slice has not expired yet + * but will expire soon (4-5 ns) during select_queue(). To cover the + * case where think time is less than a jiffy, mark the queue wait + * busy if only 1 jiffy is left in the slice. + */ + if (cfqq->slice_end - jiffies == 1) + return true; + + return false; +} + static void cfq_completed_request(struct request_queue *q, struct request *rq) { struct cfq_queue *cfqq = RQ_CFQQ(rq); @@ -3016,7 +3281,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) unsigned long now; now = jiffies; - cfq_log_cfqq(cfqd, cfqq, "complete"); + cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", !!rq_noidle(rq)); cfq_update_hw_tag(cfqd); @@ -3030,7 +3295,8 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) if (sync) { RQ_CIC(rq)->last_end_request = now; - cfqd->last_end_sync_rq = now; + if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) + cfqd->last_delayed_sync = now; } /* @@ -3044,6 +3310,16 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) cfq_set_prio_slice(cfqd, cfqq); cfq_clear_cfqq_slice_new(cfqq); } + + /* + * Should we wait for next request to come in before we expire + * the queue. + */ + if (cfq_should_wait_busy(cfqd, cfqq)) { + cfqq->slice_end = jiffies + cfqd->cfq_slice_idle; + cfq_mark_cfqq_wait_busy(cfqq); + } + /* * Idling is not enabled on: * - expired queues @@ -3063,7 +3339,8 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) * only if we processed at least one !rq_noidle request */ if (cfqd->serving_type == SYNC_WORKLOAD - || cfqd->noidle_tree_requires_idle) + || cfqd->noidle_tree_requires_idle + || cfqq->cfqg->nr_cfqq == 1) cfq_arm_slice_timer(cfqd); } } @@ -3167,14 +3444,6 @@ cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, return cic_to_cfqq(cic, 1); } -static int should_split_cfqq(struct cfq_queue *cfqq) -{ - if (cfqq->seeky_start && - time_after(jiffies, cfqq->seeky_start + CFQQ_COOP_TOUT)) - return 1; - return 0; -} - /* * Returns NULL if a new cfqq should be allocated, or the old cfqq if this * was the last process referring to said cfqq. @@ -3183,9 +3452,9 @@ static struct cfq_queue * split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq) { if (cfqq_process_refs(cfqq) == 1) { - cfqq->seeky_start = 0; cfqq->pid = current->pid; cfq_clear_cfqq_coop(cfqq); + cfq_clear_cfqq_split_coop(cfqq); return cfqq; } @@ -3224,7 +3493,7 @@ new_queue: /* * If the queue was seeky for too long, break it apart. */ - if (cfq_cfqq_coop(cfqq) && should_split_cfqq(cfqq)) { + if (cfq_cfqq_coop(cfqq) && cfq_cfqq_split_coop(cfqq)) { cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); cfqq = split_cfqq(cic, cfqq); if (!cfqq) @@ -3348,6 +3617,11 @@ static void cfq_put_async_queues(struct cfq_data *cfqd) cfq_put_queue(cfqd->async_idle_cfqq); } +static void cfq_cfqd_free(struct rcu_head *head) +{ + kfree(container_of(head, struct cfq_data, rcu)); +} + static void cfq_exit_queue(struct elevator_queue *e) { struct cfq_data *cfqd = e->elevator_data; @@ -3369,12 +3643,15 @@ static void cfq_exit_queue(struct elevator_queue *e) } cfq_put_async_queues(cfqd); + cfq_release_cfq_groups(cfqd); + blkiocg_del_blkio_group(&cfqd->root_group.blkg); spin_unlock_irq(q->queue_lock); cfq_shutdown_timer_wq(cfqd); - kfree(cfqd); + /* Wait for cfqg->blkg->key accessors to exit their grace periods. */ + call_rcu(&cfqd->rcu, cfq_cfqd_free); } static void *cfq_init_queue(struct request_queue *q) @@ -3401,7 +3678,13 @@ static void *cfq_init_queue(struct request_queue *q) cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; #ifdef CONFIG_CFQ_GROUP_IOSCHED - blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd); + /* + * Take a reference to root group which we never drop. This is just + * to make sure that cfq_put_cfqg() does not try to kfree root group + */ + atomic_set(&cfqg->ref, 1); + blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd, + 0); #endif /* * Not strictly needed (since RB_ROOT just clears the node and we @@ -3440,8 +3723,14 @@ static void *cfq_init_queue(struct request_queue *q) cfqd->cfq_slice_async_rq = cfq_slice_async_rq; cfqd->cfq_slice_idle = cfq_slice_idle; cfqd->cfq_latency = 1; + cfqd->cfq_group_isolation = 0; cfqd->hw_tag = -1; - cfqd->last_end_sync_rq = jiffies; + /* + * we optimistically start assuming sync ops weren't delayed in last + * second, in order to have larger depth for async operations. + */ + cfqd->last_delayed_sync = jiffies - HZ; + INIT_RCU_HEAD(&cfqd->rcu); return cfqd; } @@ -3510,6 +3799,7 @@ SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0); +SHOW_FUNCTION(cfq_group_isolation_show, cfqd->cfq_group_isolation, 0); #undef SHOW_FUNCTION #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ @@ -3542,6 +3832,7 @@ STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0); +STORE_FUNCTION(cfq_group_isolation_store, &cfqd->cfq_group_isolation, 0, 1, 0); #undef STORE_FUNCTION #define CFQ_ATTR(name) \ @@ -3558,6 +3849,7 @@ static struct elv_fs_entry cfq_attrs[] = { CFQ_ATTR(slice_async_rq), CFQ_ATTR(slice_idle), CFQ_ATTR(low_latency), + CFQ_ATTR(group_isolation), __ATTR_NULL }; @@ -3587,6 +3879,17 @@ static struct elevator_type iosched_cfq = { .elevator_owner = THIS_MODULE, }; +#ifdef CONFIG_CFQ_GROUP_IOSCHED +static struct blkio_policy_type blkio_policy_cfq = { + .ops = { + .blkio_unlink_group_fn = cfq_unlink_blkio_group, + .blkio_update_group_weight_fn = cfq_update_blkio_group_weight, + }, +}; +#else +static struct blkio_policy_type blkio_policy_cfq; +#endif + static int __init cfq_init(void) { /* @@ -3601,6 +3904,7 @@ static int __init cfq_init(void) return -ENOMEM; elv_register(&iosched_cfq); + blkio_policy_register(&blkio_policy_cfq); return 0; } @@ -3608,6 +3912,7 @@ static int __init cfq_init(void) static void __exit cfq_exit(void) { DECLARE_COMPLETION_ONSTACK(all_gone); + blkio_policy_unregister(&blkio_policy_cfq); elv_unregister(&iosched_cfq); ioc_gone = &all_gone; /* ioc_gone's update must be visible before reading ioc_count */