X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=block%2Fcfq-iosched.c;h=ee130f14d1fc9228214fb7d0acbd3d4f4a85acdd;hp=99ac4304d711e093867040d49ace530e832876db;hb=e071041be037eca208b62b84469a06bdfc692bea;hpb=2e46e8b27aa57c6bd34b3102b40ee4d0144b4fab diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 99ac430..ee130f1 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -9,9 +9,11 @@ #include #include #include +#include #include #include #include +#include "blk-cgroup.h" /* * tunables @@ -27,6 +29,8 @@ static const int cfq_slice_sync = HZ / 10; static int cfq_slice_async = HZ / 25; static const int cfq_slice_async_rq = 2; static int cfq_slice_idle = HZ / 125; +static const int cfq_target_latency = HZ * 3/10; /* 300 ms */ +static const int cfq_hist_divisor = 4; /* * offset from end of service tree @@ -38,8 +42,15 @@ static int cfq_slice_idle = HZ / 125; */ #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 RQ_CIC(rq) \ ((struct cfq_io_context *) (rq)->elevator_private) @@ -48,7 +59,7 @@ static int cfq_slice_idle = HZ / 125; static struct kmem_cache *cfq_pool; static struct kmem_cache *cfq_ioc_pool; -static DEFINE_PER_CPU(unsigned long, ioc_count); +static DEFINE_PER_CPU(unsigned long, cfq_ioc_count); static struct completion *ioc_gone; static DEFINE_SPINLOCK(ioc_gone_lock); @@ -57,6 +68,7 @@ static DEFINE_SPINLOCK(ioc_gone_lock); #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) #define sample_valid(samples) ((samples) > 80) +#define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) /* * Most of our rbtree usage is for sorting with min extraction, so @@ -67,19 +79,144 @@ static DEFINE_SPINLOCK(ioc_gone_lock); struct cfq_rb_root { struct rb_root rb; struct rb_node *left; + unsigned count; + u64 min_vdisktime; + struct rb_node *active; + unsigned total_weight; +}; +#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, 0, 0, } + +/* + * Per process-grouping structure + */ +struct cfq_queue { + /* reference count */ + atomic_t ref; + /* various state flags, see below */ + unsigned int flags; + /* parent cfq_data */ + struct cfq_data *cfqd; + /* service_tree member */ + struct rb_node rb_node; + /* service_tree key */ + unsigned long rb_key; + /* prio tree member */ + struct rb_node p_node; + /* prio tree root we belong to, if any */ + struct rb_root *p_root; + /* sorted list of pending requests */ + struct rb_root sort_list; + /* if fifo isn't expired, next request to serve */ + struct request *next_rq; + /* requests queued in sort_list */ + int queued[2]; + /* currently allocated requests */ + int allocated[2]; + /* fifo list of requests in sort_list */ + struct list_head fifo; + + /* 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; + long slice_resid; + unsigned int slice_dispatch; + + /* pending metadata requests */ + int meta_pending; + /* number of requests that are on the dispatch list or inside driver */ + int dispatched; + + /* io prio of this group */ + unsigned short ioprio, org_ioprio; + unsigned short ioprio_class, org_ioprio_class; + + unsigned int seek_samples; + 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; +}; + +/* + * First index in the service_trees. + * IDLE is handled separately, so it has negative index + */ +enum wl_prio_t { + BE_WORKLOAD = 0, + RT_WORKLOAD = 1, + IDLE_WORKLOAD = 2, +}; + +/* + * Second index in the service_trees. + */ +enum wl_type_t { + ASYNC_WORKLOAD = 0, + SYNC_NOIDLE_WORKLOAD = 1, + SYNC_WORKLOAD = 2 +}; + +/* This is per cgroup per device grouping structure */ +struct cfq_group { + /* group service_tree member */ + struct rb_node rb_node; + + /* group service_tree key */ + u64 vdisktime; + unsigned int weight; + bool on_st; + + /* number of cfqq currently on this group */ + int nr_cfqq; + + /* Per group busy queus average. Useful for workload slice calc. */ + unsigned int busy_queues_avg[2]; + /* + * rr lists of queues with requests, onle rr for each priority class. + * Counts are embedded in the cfq_rb_root + */ + struct cfq_rb_root service_trees[2][3]; + struct cfq_rb_root service_tree_idle; + + unsigned long saved_workload_slice; + enum wl_type_t saved_workload; + enum wl_prio_t saved_serving_prio; + struct blkio_group blkg; +#ifdef CONFIG_CFQ_GROUP_IOSCHED + struct hlist_node cfqd_node; + atomic_t ref; +#endif }; -#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, } /* * Per block device queue structure */ struct cfq_data { struct request_queue *queue; + /* Root service tree for cfq_groups */ + struct cfq_rb_root grp_service_tree; + struct cfq_group root_group; /* - * rr list of queues with requests and the count of them + * The priority currently being served */ - struct cfq_rb_root service_tree; + enum wl_prio_t serving_prio; + enum wl_type_t serving_type; + unsigned long workload_expires; + struct cfq_group *serving_group; + bool noidle_tree_requires_idle; /* * Each priority tree is sorted by next_request position. These @@ -89,13 +226,8 @@ struct cfq_data { 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 rq_in_driver[2]; int sync_flight; /* @@ -103,8 +235,14 @@ struct cfq_data { */ int rq_queued; int hw_tag; - int hw_tag_samples; - int rq_in_driver_peak; + /* + * hw_tag can be + * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection) + * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth) + * 0 => no NCQ + */ + int hw_tag_est_depth; + unsigned int hw_tag_samples; /* * idle window management @@ -122,7 +260,6 @@ struct cfq_data { struct cfq_queue *async_idle_cfqq; sector_t last_position; - unsigned long last_end_request; /* * tunables, see top of file @@ -134,67 +271,51 @@ struct cfq_data { unsigned int cfq_slice[2]; 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; -}; -/* - * Per process-grouping structure - */ -struct cfq_queue { - /* reference count */ - atomic_t ref; - /* various state flags, see below */ - unsigned int flags; - /* parent cfq_data */ - struct cfq_data *cfqd; - /* service_tree member */ - struct rb_node rb_node; - /* service_tree key */ - unsigned long rb_key; - /* prio tree member */ - struct rb_node p_node; - /* prio tree root we belong to, if any */ - struct rb_root *p_root; - /* sorted list of pending requests */ - struct rb_root sort_list; - /* if fifo isn't expired, next request to serve */ - struct request *next_rq; - /* requests queued in sort_list */ - int queued[2]; - /* currently allocated requests */ - int allocated[2]; - /* fifo list of requests in sort_list */ - struct list_head fifo; + /* + * Fallback dummy cfqq for extreme OOM conditions + */ + struct cfq_queue oom_cfqq; - unsigned long slice_end; - long slice_resid; - unsigned int slice_dispatch; + unsigned long last_delayed_sync; - /* pending metadata requests */ - int meta_pending; - /* number of requests that are on the dispatch list or inside driver */ - int dispatched; + /* List of cfq groups being managed on this device*/ + struct hlist_head cfqg_list; + struct rcu_head rcu; +}; - /* io prio of this group */ - unsigned short ioprio, org_ioprio; - unsigned short ioprio_class, org_ioprio_class; +static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd); - pid_t pid; -}; +static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg, + enum wl_prio_t prio, + enum wl_type_t type) +{ + if (!cfqg) + return NULL; + + if (prio == IDLE_WORKLOAD) + return &cfqg->service_tree_idle; + + return &cfqg->service_trees[prio][type]; +} 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_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_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 */ + CFQ_CFQQ_FLAG_coop, /* cfqq is shared */ + CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */ + CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */ }; #define CFQ_CFQQ_FNS(name) \ @@ -214,7 +335,6 @@ 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(fifo_expire); CFQ_CFQQ_FNS(idle_window); @@ -222,41 +342,107 @@ CFQ_CFQQ_FNS(prio_changed); CFQ_CFQQ_FNS(slice_new); CFQ_CFQQ_FNS(sync); CFQ_CFQQ_FNS(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) +/* Traverses through cfq group service trees */ +#define for_each_cfqg_st(cfqg, i, j, st) \ + for (i = 0; i <= IDLE_WORKLOAD; i++) \ + for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\ + : &cfqg->service_tree_idle; \ + (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \ + (i == IDLE_WORKLOAD && j == 0); \ + j++, st = i < IDLE_WORKLOAD ? \ + &cfqg->service_trees[i][j]: NULL) \ + + +static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq) +{ + if (cfq_class_idle(cfqq)) + return IDLE_WORKLOAD; + if (cfq_class_rt(cfqq)) + return RT_WORKLOAD; + return BE_WORKLOAD; +} + + +static enum wl_type_t cfqq_type(struct cfq_queue *cfqq) +{ + if (!cfq_cfqq_sync(cfqq)) + return ASYNC_WORKLOAD; + if (!cfq_cfqq_idle_window(cfqq)) + return SYNC_NOIDLE_WORKLOAD; + return SYNC_WORKLOAD; +} + +static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl, + struct cfq_data *cfqd, + struct cfq_group *cfqg) +{ + if (wl == IDLE_WORKLOAD) + return cfqg->service_tree_idle.count; + + return cfqg->service_trees[wl][ASYNC_WORKLOAD].count + + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count + + 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 *, int, +static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, struct io_context *, gfp_t); static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, struct io_context *); +static inline int rq_in_driver(struct cfq_data *cfqd) +{ + return cfqd->rq_in_driver[0] + cfqd->rq_in_driver[1]; +} + static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, - int is_sync) + bool is_sync) { - return cic->cfqq[!!is_sync]; + return cic->cfqq[is_sync]; } static inline void cic_set_cfqq(struct cfq_io_context *cic, - struct cfq_queue *cfqq, int is_sync) + struct cfq_queue *cfqq, bool is_sync) { - cic->cfqq[!!is_sync] = cfqq; + cic->cfqq[is_sync] = cfqq; } /* * We regard a request as SYNC, if it's either a read or has the SYNC bit * set (in which case it could also be direct WRITE). */ -static inline int cfq_bio_sync(struct bio *bio) +static inline bool cfq_bio_sync(struct bio *bio) { - if (bio_data_dir(bio) == READ || bio_sync(bio)) - return 1; - - return 0; + return bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO); } /* @@ -275,7 +461,7 @@ static int cfq_queue_empty(struct request_queue *q) { struct cfq_data *cfqd = q->elevator->elevator_data; - return !cfqd->busy_queues; + return !cfqd->rq_queued; } /* @@ -283,7 +469,7 @@ static int cfq_queue_empty(struct request_queue *q) * if a queue is marked sync and has sync io queued. A sync queue with async * io only, should not get full sync slice length. */ -static inline int cfq_prio_slice(struct cfq_data *cfqd, int sync, +static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync, unsigned short prio) { const int base_slice = cfqd->cfq_slice[sync]; @@ -299,10 +485,110 @@ cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); } +static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) +{ + u64 d = delta << CFQ_SERVICE_SHIFT; + + d = d * BLKIO_WEIGHT_DEFAULT; + do_div(d, cfqg->weight); + return d; +} + +static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) +{ + s64 delta = (s64)(vdisktime - min_vdisktime); + if (delta > 0) + min_vdisktime = vdisktime; + + return min_vdisktime; +} + +static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) +{ + s64 delta = (s64)(vdisktime - min_vdisktime); + if (delta < 0) + min_vdisktime = vdisktime; + + return min_vdisktime; +} + +static void update_min_vdisktime(struct cfq_rb_root *st) +{ + u64 vdisktime = st->min_vdisktime; + struct cfq_group *cfqg; + + if (st->active) { + cfqg = rb_entry_cfqg(st->active); + vdisktime = cfqg->vdisktime; + } + + if (st->left) { + cfqg = rb_entry_cfqg(st->left); + vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime); + } + + st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime); +} + +/* + * get averaged number of queues of RT/BE priority. + * average is updated, with a formula that gives more weight to higher numbers, + * to quickly follows sudden increases and decrease slowly + */ + +static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd, + struct cfq_group *cfqg, bool rt) +{ + unsigned min_q, max_q; + unsigned mult = cfq_hist_divisor - 1; + unsigned round = cfq_hist_divisor / 2; + unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg); + + min_q = min(cfqg->busy_queues_avg[rt], busy); + max_q = max(cfqg->busy_queues_avg[rt], busy); + cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) / + cfq_hist_divisor; + return cfqg->busy_queues_avg[rt]; +} + +static inline unsigned +cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) +{ + struct cfq_rb_root *st = &cfqd->grp_service_tree; + + return cfq_target_latency * cfqg->weight / st->total_weight; +} + static inline void cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) { - cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; + unsigned slice = cfq_prio_to_slice(cfqd, cfqq); + if (cfqd->cfq_latency) { + /* + * interested queues (we consider only the ones with the same + * priority class in the cfq group) + */ + unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg, + cfq_class_rt(cfqq)); + unsigned sync_slice = cfqd->cfq_slice[1]; + unsigned expect_latency = sync_slice * iq; + unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg); + + if (expect_latency > group_slice) { + unsigned base_low_slice = 2 * cfqd->cfq_slice_idle; + /* scale low_slice according to IO priority + * and sync vs async */ + unsigned low_slice = + min(slice, base_low_slice * slice / sync_slice); + /* the adapted slice value is scaled to fit all iqs + * into the target latency */ + slice = max(slice * group_slice / expect_latency, + low_slice); + } + } + 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); } @@ -311,7 +597,7 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) * isn't valid until the first request from the dispatch is activated * and the slice time set. */ -static inline int cfq_slice_used(struct cfq_queue *cfqq) +static inline bool cfq_slice_used(struct cfq_queue *cfqq) { if (cfq_cfqq_slice_new(cfqq)) return 0; @@ -327,9 +613,9 @@ static inline int cfq_slice_used(struct cfq_queue *cfqq) * behind the head is penalized and only allowed to a certain extent. */ static struct request * -cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2) +cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last) { - sector_t last, s1, s2, d1 = 0, d2 = 0; + sector_t s1, s2, d1 = 0, d2 = 0; unsigned long back_max; #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ @@ -352,8 +638,6 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2) s1 = blk_rq_pos(rq1); s2 = blk_rq_pos(rq2); - last = cfqd->last_position; - /* * by definition, 1KiB is 2 sectors */ @@ -421,6 +705,10 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2) */ static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) { + /* Service tree is empty */ + if (!root->count) + return NULL; + if (!root->left) root->left = rb_first(&root->rb); @@ -430,6 +718,17 @@ static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) return NULL; } +static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) +{ + if (!root->left) + root->left = rb_first(&root->rb); + + if (root->left) + return rb_entry_cfqg(root->left); + + return NULL; +} + static void rb_erase_init(struct rb_node *n, struct rb_root *root) { rb_erase(n, root); @@ -441,6 +740,7 @@ static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) if (root->left == n) root->left = NULL; rb_erase_init(n, &root->rb); + --root->count; } /* @@ -467,7 +767,7 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, next = rb_entry_rq(rbnext); } - return cfq_choose_req(cfqd, next, prev); + return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); } static unsigned long cfq_slice_offset(struct cfq_data *cfqd, @@ -476,51 +776,417 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd, /* * just an approximation, should be ok. */ - return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) - + return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) - cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); } +static inline s64 +cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) +{ + return cfqg->vdisktime - st->min_vdisktime; +} + +static void +__cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) +{ + struct rb_node **node = &st->rb.rb_node; + struct rb_node *parent = NULL; + struct cfq_group *__cfqg; + s64 key = cfqg_key(st, cfqg); + int left = 1; + + while (*node != NULL) { + parent = *node; + __cfqg = rb_entry_cfqg(parent); + + if (key < cfqg_key(st, __cfqg)) + node = &parent->rb_left; + else { + node = &parent->rb_right; + left = 0; + } + } + + if (left) + st->left = &cfqg->rb_node; + + rb_link_node(&cfqg->rb_node, parent, node); + rb_insert_color(&cfqg->rb_node, &st->rb); +} + +static void +cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg) +{ + struct cfq_rb_root *st = &cfqd->grp_service_tree; + struct cfq_group *__cfqg; + struct rb_node *n; + + cfqg->nr_cfqq++; + if (cfqg->on_st) + return; + + /* + * Currently put the group at the end. Later implement something + * so that groups get lesser vtime based on their weights, so that + * if group does not loose all if it was not continously backlogged. + */ + n = rb_last(&st->rb); + if (n) { + __cfqg = rb_entry_cfqg(n); + cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; + } else + cfqg->vdisktime = st->min_vdisktime; + + __cfq_group_service_tree_add(st, cfqg); + cfqg->on_st = true; + st->total_weight += cfqg->weight; +} + +static void +cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg) +{ + struct cfq_rb_root *st = &cfqd->grp_service_tree; + + if (st->active == &cfqg->rb_node) + st->active = NULL; + + BUG_ON(cfqg->nr_cfqq < 1); + cfqg->nr_cfqq--; + + /* If there are other cfq queues under this group, don't delete it */ + if (cfqg->nr_cfqq) + return; + + cfq_log_cfqg(cfqd, cfqg, "del_from_rr group"); + cfqg->on_st = false; + 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; + + /* + * Queue got expired before even a single request completed or + * got expired immediately after first request completion. + */ + if (!cfqq->slice_start || cfqq->slice_start == jiffies) { + /* + * Also charge the seek time incurred to the group, otherwise + * if there are mutiple queues in the group, each can dispatch + * a single request on seeky media and cause lots of seek time + * and group will never know it. + */ + slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start), + 1); + } else { + slice_used = jiffies - cfqq->slice_start; + if (slice_used > cfqq->allocated_slice) + slice_used = cfqq->allocated_slice; + } + + cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u sect=%lu", slice_used, + cfqq->nr_sectors); + return slice_used; +} + +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, 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); + + 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(charge_sl, cfqg); + __cfq_group_service_tree_add(st, cfqg); + + /* This group is being expired. Save the context */ + if (time_after(cfqd->workload_expires, jiffies)) { + cfqg->saved_workload_slice = cfqd->workload_expires + - jiffies; + cfqg->saved_workload = cfqd->serving_type; + 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 +static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) +{ + if (blkg) + return container_of(blkg, struct cfq_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) +{ + struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); + struct cfq_group *cfqg = NULL; + 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 (!blkiocg_css_tryget(blkcg)) + return NULL;; + + cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); + if (cfqg || !create) + goto done; + + cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); + if (!cfqg) + goto done; + + cfqg->weight = blkcg->weight; + for_each_cfqg_st(cfqg, i, j, st) + *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 */ + 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: + blkiocg_css_put(blkcg); + return cfqg; +} + +/* + * Search for the cfq group current task belongs to. If create = 1, then also + * create the cfq group if it does not exist. request_queue lock must be held. + */ +static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create) +{ + struct cgroup *cgroup; + struct cfq_group *cfqg = NULL; + + rcu_read_lock(); + cgroup = task_cgroup(current, blkio_subsys_id); + cfqg = cfq_find_alloc_cfqg(cfqd, cgroup, create); + if (!cfqg && create) + cfqg = &cfqd->root_group; + rcu_read_unlock(); + return cfqg; +} + +static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) +{ + /* Currently, all async queues are mapped to root group */ + if (!cfq_cfqq_sync(cfqq)) + 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) +{ + return &cfqd->root_group; +} +static inline void +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 */ + /* - * The cfqd->service_tree holds all pending cfq_queue's that have + * The cfqd->service_trees holds all pending cfq_queue's that have * 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) + bool add_front) { struct rb_node **p, *parent; struct cfq_queue *__cfqq; unsigned long rb_key; + 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)); if (cfq_class_idle(cfqq)) { rb_key = CFQ_IDLE_DELAY; - parent = rb_last(&cfqd->service_tree.rb); + parent = rb_last(&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) { + /* + * Get our rb key offset. Subtract any residual slice + * value carried from last service. A negative resid + * count indicates slice overrun, and this should position + * the next service time further away in the tree. + */ rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; - rb_key += cfqq->slice_resid; + rb_key -= cfqq->slice_resid; cfqq->slice_resid = 0; - } else - rb_key = 0; + } else { + rb_key = -HZ; + __cfqq = cfq_rb_first(service_tree); + rb_key += __cfqq ? __cfqq->rb_key : jiffies; + } if (!RB_EMPTY_NODE(&cfqq->rb_node)) { + new_cfqq = 0; /* * same position, nothing more to do */ - if (rb_key == cfqq->rb_key) + if (rb_key == cfqq->rb_key && + cfqq->service_tree == service_tree) return; - cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); + cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); + cfqq->service_tree = NULL; } left = 1; parent = NULL; - p = &cfqd->service_tree.rb.rb_node; + cfqq->service_tree = service_tree; + p = &service_tree->rb.rb_node; while (*p) { struct rb_node **n; @@ -528,35 +1194,28 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, __cfqq = rb_entry(parent, struct cfq_queue, rb_node); /* - * sort RT queues first, we always want to give - * preference to them. IDLE queues goes to the back. - * after that, sort on the next service time. + * sort by key, that represents service time. */ - if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq)) - n = &(*p)->rb_left; - else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq)) - n = &(*p)->rb_right; - else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq)) + if (time_before(rb_key, __cfqq->rb_key)) n = &(*p)->rb_left; - else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq)) - n = &(*p)->rb_right; - else if (rb_key < __cfqq->rb_key) - n = &(*p)->rb_left; - else + else { n = &(*p)->rb_right; - - if (n == &(*p)->rb_right) left = 0; + } p = n; } if (left) - cfqd->service_tree.left = &cfqq->rb_node; + service_tree->left = &cfqq->rb_node; cfqq->rb_key = rb_key; rb_link_node(&cfqq->rb_node, parent, p); - rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb); + rb_insert_color(&cfqq->rb_node, &service_tree->rb); + service_tree->count++; + if ((add_front || !new_cfqq) && !group_changed) + return; + cfq_group_service_tree_add(cfqd, cfqq->cfqg); } static struct cfq_queue * @@ -644,8 +1303,6 @@ 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); } @@ -660,17 +1317,18 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) BUG_ON(!cfq_cfqq_on_rr(cfqq)); cfq_clear_cfqq_on_rr(cfqq); - if (!RB_EMPTY_NODE(&cfqq->rb_node)) - cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); + if (!RB_EMPTY_NODE(&cfqq->rb_node)) { + cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); + cfqq->service_tree = NULL; + } if (cfqq->p_root) { rb_erase(&cfqq->p_node, cfqq->p_root); cfqq->p_root = NULL; } + cfq_group_service_tree_del(cfqd, cfqq->cfqg); BUG_ON(!cfqd->busy_queues); cfqd->busy_queues--; - if (cfq_class_rt(cfqq)) - cfqd->busy_rt_queues--; } /* @@ -679,7 +1337,6 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) static void cfq_del_rq_rb(struct request *rq) { struct cfq_queue *cfqq = RQ_CFQQ(rq); - struct cfq_data *cfqd = cfqq->cfqd; const int sync = rq_is_sync(rq); BUG_ON(!cfqq->queued[sync]); @@ -687,8 +1344,17 @@ static void cfq_del_rq_rb(struct request *rq) elv_rb_del(&cfqq->sort_list, rq); - if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) - cfq_del_cfqq_rr(cfqd, cfqq); + if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { + /* + * Queue will be deleted from service tree when we actually + * expire it later. Right now just remove it from prio tree + * as it is empty. + */ + if (cfqq->p_root) { + rb_erase(&cfqq->p_node, cfqq->p_root); + cfqq->p_root = NULL; + } + } } static void cfq_add_rq_rb(struct request *rq) @@ -713,7 +1379,7 @@ 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); + cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position); /* * adjust priority tree position, if ->next_rq changes @@ -756,9 +1422,9 @@ static void cfq_activate_request(struct request_queue *q, struct request *rq) { struct cfq_data *cfqd = q->elevator->elevator_data; - cfqd->rq_in_driver++; + cfqd->rq_in_driver[rq_is_sync(rq)]++; cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", - cfqd->rq_in_driver); + rq_in_driver(cfqd)); cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); } @@ -766,11 +1432,12 @@ static void cfq_activate_request(struct request_queue *q, struct request *rq) static void cfq_deactivate_request(struct request_queue *q, struct request *rq) { struct cfq_data *cfqd = q->elevator->elevator_data; + const int sync = rq_is_sync(rq); - WARN_ON(!cfqd->rq_in_driver); - cfqd->rq_in_driver--; + WARN_ON(!cfqd->rq_in_driver[sync]); + cfqd->rq_in_driver[sync]--; cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", - cfqd->rq_in_driver); + rq_in_driver(cfqd)); } static void cfq_remove_request(struct request *rq) @@ -819,13 +1486,18 @@ static void cfq_merged_requests(struct request_queue *q, struct request *rq, struct request *next) { + struct cfq_queue *cfqq = RQ_CFQQ(rq); /* * reposition in fifo if next is older than rq */ if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && - time_before(next->start_time, rq->start_time)) + time_before(rq_fifo_time(next), rq_fifo_time(rq))) { list_move(&rq->queuelist, &next->queuelist); + rq_set_fifo_time(rq, rq_fifo_time(next)); + } + if (cfqq->next_rq == next) + cfqq->next_rq = rq; cfq_remove_request(next); } @@ -840,7 +1512,7 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq, * Disallow merge of a sync bio into an async request. */ if (cfq_bio_sync(bio) && !rq_is_sync(rq)) - return 0; + return false; /* * Lookup the cfqq that this bio will be queued with. Allow @@ -848,13 +1520,10 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq, */ cic = cfq_cic_lookup(cfqd, current->io_context); if (!cic) - return 0; + return false; cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); - if (cfqq == RQ_CFQQ(rq)) - return 1; - - return 0; + return cfqq == RQ_CFQQ(rq); } static void __cfq_set_active_queue(struct cfq_data *cfqd, @@ -862,8 +1531,12 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd, { if (cfqq) { 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); @@ -882,7 +1555,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd, */ static void __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, - int timed_out) + bool timed_out) { cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); @@ -890,6 +1563,7 @@ __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); /* * store what was left of this slice, if the queue idled/timed out @@ -899,18 +1573,26 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); } + cfq_group_served(cfqd, cfqq->cfqg, cfqq); + + if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) + cfq_del_cfqq_rr(cfqd, cfqq); + cfq_resort_rr_list(cfqd, cfqq); if (cfqq == cfqd->active_queue) cfqd->active_queue = NULL; + if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active) + cfqd->grp_service_tree.active = NULL; + if (cfqd->active_cic) { put_io_context(cfqd->active_cic->ioc); cfqd->active_cic = NULL; } } -static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out) +static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) { struct cfq_queue *cfqq = cfqd->active_queue; @@ -924,10 +1606,39 @@ static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out) */ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) { - if (RB_EMPTY_ROOT(&cfqd->service_tree.rb)) + struct cfq_rb_root *service_tree = + service_tree_for(cfqd->serving_group, cfqd->serving_prio, + cfqd->serving_type); + + if (!cfqd->rq_queued) return NULL; - return cfq_rb_first(&cfqd->service_tree); + /* There is nothing to dispatch */ + if (!service_tree) + return NULL; + if (RB_EMPTY_ROOT(&service_tree->rb)) + return NULL; + return cfq_rb_first(service_tree); +} + +static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) +{ + struct cfq_group *cfqg; + struct cfq_queue *cfqq; + int i, j; + struct cfq_rb_root *st; + + if (!cfqd->rq_queued) + return NULL; + + cfqg = cfq_get_next_cfqg(cfqd); + if (!cfqg) + return NULL; + + for_each_cfqg_st(cfqg, i, j, st) + if ((cfqq = cfq_rb_first(st)) != NULL) + return cfqq; + return NULL; } /* @@ -936,11 +1647,8 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) { - if (!cfqq) { + if (!cfqq) cfqq = cfq_get_next_queue(cfqd); - if (cfqq) - cfq_clear_cfqq_coop(cfqq); - } __cfq_set_active_queue(cfqd, cfqq); return cfqq; @@ -955,16 +1663,20 @@ static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, return cfqd->last_position - blk_rq_pos(rq); } -#define CIC_SEEK_THR 8 * 1024 -#define CIC_SEEKY(cic) ((cic)->seek_mean > CIC_SEEK_THR) +#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 request *rq) +static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, + struct request *rq, bool for_preempt) { - struct cfq_io_context *cic = cfqd->active_cic; - sector_t sdist = cic->seek_mean; + sector_t sdist = cfqq->seek_mean; + + if (!sample_valid(cfqq->seek_samples)) + sdist = CFQQ_SEEK_THR; - if (!sample_valid(cic->seek_samples)) - sdist = CIC_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; } @@ -993,7 +1705,7 @@ 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, __cfqq->next_rq)) + if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false)) return __cfqq; if (blk_rq_pos(__cfqq->next_rq) < sector) @@ -1004,7 +1716,7 @@ 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, __cfqq->next_rq)) + if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false)) return __cfqq; return NULL; @@ -1021,16 +1733,19 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, * assumption. */ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, - struct cfq_queue *cur_cfqq, - int probe) + struct cfq_queue *cur_cfqq) { struct cfq_queue *cfqq; + if (!cfq_cfqq_sync(cur_cfqq)) + return NULL; + if (CFQQ_SEEKY(cur_cfqq)) + return NULL; + /* - * A valid cfq_io_context is necessary to compare requests against - * the seek_mean of the current cfqq. + * Don't search priority tree if it's the only queue in the group. */ - if (!cfqd->active_cic) + if (cur_cfqq->cfqg->nr_cfqq == 1) return NULL; /* @@ -1042,14 +1757,55 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, if (!cfqq) return NULL; - if (cfq_cfqq_coop(cfqq)) + /* 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. + */ + if (!cfq_cfqq_sync(cfqq)) + return NULL; + if (CFQQ_SEEKY(cfqq)) + return NULL; + + /* + * Do not merge queues of different priority classes + */ + if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq)) return NULL; - if (!probe) - cfq_mark_cfqq_coop(cfqq); return cfqq; } +/* + * Determine whether we should enforce idle window for this queue. + */ + +static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) +{ + enum wl_prio_t prio = cfqq_prio(cfqq); + struct cfq_rb_root *service_tree = cfqq->service_tree; + + BUG_ON(!service_tree); + BUG_ON(!service_tree->count); + + /* We never do for idle class queues. */ + if (prio == IDLE_WORKLOAD) + return false; + + /* We do for queues that were marked with idle window flag. */ + 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; +} + static void cfq_arm_slice_timer(struct cfq_data *cfqd) { struct cfq_queue *cfqq = cfqd->active_queue; @@ -1070,13 +1826,13 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) /* * idle is disabled, either manually or by past process history */ - if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq)) + if (!cfqd->cfq_slice_idle || !cfq_should_idle(cfqd, cfqq)) return; /* - * still requests with the driver, don't idle + * still active requests from this queue, don't idle */ - if (cfqd->rq_in_driver) + if (cfqq->dispatched) return; /* @@ -1086,16 +1842,18 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) if (!cic || !atomic_read(&cic->ioc->nr_tasks)) return; - cfq_mark_cfqq_wait_request(cfqq); - /* - * 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 - * seeks. so allow a little bit of time for him to submit a new rq + * If our average think time is larger than the remaining time + * slice, then don't idle. This avoids overrunning the allotted + * time slice. */ + if (sample_valid(cic->ttime_samples) && + (cfqq->slice_end - jiffies < cic->ttime_mean)) + return; + + cfq_mark_cfqq_wait_request(cfqq); + sl = cfqd->cfq_slice_idle; - if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic)) - sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT)); mod_timer(&cfqd->idle_slice_timer, jiffies + sl); cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl); @@ -1111,12 +1869,14 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); + cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); cfq_remove_request(rq); cfqq->dispatched++; elv_dispatch_sort(q, rq); if (cfq_cfqq_sync(cfqq)) cfqd->sync_flight++; + cfqq->nr_sectors += blk_rq_sectors(rq); } /* @@ -1124,9 +1884,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) */ static struct request *cfq_check_fifo(struct cfq_queue *cfqq) { - struct cfq_data *cfqd = cfqq->cfqd; - struct request *rq; - int fifo; + struct request *rq = NULL; if (cfq_cfqq_fifo_expire(cfqq)) return NULL; @@ -1136,24 +1894,202 @@ static struct request *cfq_check_fifo(struct cfq_queue *cfqq) if (list_empty(&cfqq->fifo)) return NULL; - fifo = cfq_cfqq_sync(cfqq); rq = rq_entry_fifo(cfqq->fifo.next); - - if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) + if (time_before(jiffies, rq_fifo_time(rq))) rq = NULL; - cfq_log_cfqq(cfqd, cfqq, "fifo=%p", rq); + cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq); return rq; } -static inline int -cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) +static inline int +cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) +{ + const int base_rq = cfqd->cfq_slice_async_rq; + + WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); + + return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); +} + +/* + * Must be called with the queue_lock held. + */ +static int cfqq_process_refs(struct cfq_queue *cfqq) +{ + int process_refs, io_refs; + + io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE]; + process_refs = atomic_read(&cfqq->ref) - io_refs; + BUG_ON(process_refs < 0); + return process_refs; +} + +static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq) +{ + int process_refs, new_process_refs; + struct cfq_queue *__cfqq; + + /* Avoid a circular list and skip interim queue merges */ + while ((__cfqq = new_cfqq->new_cfqq)) { + if (__cfqq == cfqq) + return; + new_cfqq = __cfqq; + } + + process_refs = cfqq_process_refs(cfqq); + /* + * If the process for the cfqq has gone away, there is no + * sense in merging the queues. + */ + if (process_refs == 0) + return; + + /* + * Merge in the direction of the lesser amount of work. + */ + new_process_refs = cfqq_process_refs(new_cfqq); + if (new_process_refs >= process_refs) { + cfqq->new_cfqq = new_cfqq; + atomic_add(process_refs, &new_cfqq->ref); + } else { + new_cfqq->new_cfqq = cfqq; + atomic_add(new_process_refs, &cfqq->ref); + } +} + +static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, + struct cfq_group *cfqg, enum wl_prio_t prio) +{ + struct cfq_queue *queue; + int i; + bool key_valid = false; + unsigned long lowest_key = 0; + enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; + + 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; + cur_best = i; + key_valid = true; + } + } + + return cur_best; +} + +static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) +{ + unsigned slice; + unsigned count; + struct cfq_rb_root *st; + unsigned group_slice; + + if (!cfqg) { + cfqd->serving_prio = IDLE_WORKLOAD; + cfqd->workload_expires = jiffies + 1; + return; + } + + /* Choose next priority. RT > BE > IDLE */ + if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg)) + cfqd->serving_prio = RT_WORKLOAD; + else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg)) + cfqd->serving_prio = BE_WORKLOAD; + else { + cfqd->serving_prio = IDLE_WORKLOAD; + cfqd->workload_expires = jiffies + 1; + return; + } + + /* + * For RT and BE, we have to choose also the type + * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload + * expiration time + */ + st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); + count = st->count; + + /* + * check workload expiration, and that we still have other queues ready + */ + 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); + st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type); + count = st->count; + + /* + * the workload slice is computed as a fraction of target latency + * proportional to the number of queues in that workload, over + * all the queues in the same priority class + */ + group_slice = cfq_group_slice(cfqd, cfqg); + + slice = group_slice * count / + 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) { + 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 + /* sync workload slice is at least 2 * cfq_slice_idle */ + slice = max(slice, 2 * cfqd->cfq_slice_idle); + + slice = max_t(unsigned, slice, CFQ_MIN_TT); + cfqd->workload_expires = jiffies + slice; + cfqd->noidle_tree_requires_idle = false; +} + +static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) +{ + struct cfq_rb_root *st = &cfqd->grp_service_tree; + struct cfq_group *cfqg; + + if (RB_EMPTY_ROOT(&st->rb)) + return NULL; + cfqg = cfq_rb_first_group(st); + st->active = &cfqg->rb_node; + update_min_vdisktime(st); + return cfqg; +} + +static void cfq_choose_cfqg(struct cfq_data *cfqd) { - const int base_rq = cfqd->cfq_slice_async_rq; + struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); - WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); + cfqd->serving_group = cfqg; - return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); + /* Restore the workload type data */ + if (cfqg->saved_workload_slice) { + 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); } /* @@ -1168,24 +2104,34 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) if (!cfqq) goto new_queue; + 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; /* - * If we have a RT cfqq waiting, then we pre-empt the current non-rt - * cfqq. + * The active queue has run out of time, expire it and select new. */ - if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) { + if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) { /* - * We simulate this as cfqq timed out so that it gets to bank - * the remaining of its time slice. + * 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. */ - cfq_log_cfqq(cfqd, cfqq, "preempt"); - cfq_slice_expired(cfqd, 1); - goto new_queue; + 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; } /* @@ -1199,11 +2145,14 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) * 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. + * tree. If possible, merge the expiring queue with the new cfqq. */ - new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0); - if (new_cfqq) + new_cfqq = cfq_close_cooperator(cfqd, cfqq); + if (new_cfqq) { + if (!cfqq->new_cfqq) + cfq_setup_merge(cfqq, new_cfqq); goto expire; + } /* * No requests pending. If the active queue still has requests in @@ -1211,7 +2160,7 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) * conditions to happen (or time out) before selecting a new queue. */ if (timer_pending(&cfqd->idle_slice_timer) || - (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) { + (cfqq->dispatched && cfq_should_idle(cfqd, cfqq))) { cfqq = NULL; goto keep_queue; } @@ -1219,6 +2168,13 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) expire: cfq_slice_expired(cfqd, 0); new_queue: + /* + * Current queue expired. Check if we have to switch to a new + * service tree + */ + if (!new_cfqq) + cfq_choose_cfqg(cfqd); + cfqq = cfq_set_active_queue(cfqd, new_cfqq); keep_queue: return cfqq; @@ -1234,6 +2190,9 @@ static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) } BUG_ON(!list_empty(&cfqq->fifo)); + + /* By default cfqq is not expired if it is empty. Do it explicitly */ + __cfq_slice_expired(cfqq->cfqd, cfqq, 0); return dispatched; } @@ -1246,27 +2205,93 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd) struct cfq_queue *cfqq; int dispatched = 0; - while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL) + while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) dispatched += __cfq_forced_dispatch_cfqq(cfqq); cfq_slice_expired(cfqd, 0); - BUG_ON(cfqd->busy_queues); - cfq_log(cfqd, "forced_dispatch=%d\n", dispatched); + cfq_log(cfqd, "forced_dispatch=%d", dispatched); return dispatched; } +static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq) +{ + unsigned int max_dispatch; + + /* + * Drain async requests before we start sync IO + */ + if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC]) + return false; + + /* + * 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 false; + + max_dispatch = cfqd->cfq_quantum; + if (cfq_class_idle(cfqq)) + max_dispatch = 1; + + /* + * 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)) + return false; + + /* + * We have other queues, don't allow more IO from this one + */ + if (cfqd->busy_queues > 1) + return false; + + /* + * Sole queue user, no limit + */ + max_dispatch = -1; + } + + /* + * Async queues must wait a bit before being allowed dispatch. + * We also ramp up the dispatch depth gradually for async IO, + * based on the last sync IO we serviced + */ + if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) { + unsigned long last_sync = jiffies - cfqd->last_delayed_sync; + unsigned int depth; + + depth = last_sync / cfqd->cfq_slice[1]; + if (!depth && !cfqq->dispatched) + depth = 1; + if (depth < max_dispatch) + max_dispatch = depth; + } + + /* + * If we're below the current max, allow a dispatch + */ + return cfqq->dispatched < max_dispatch; +} + /* * 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) +static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) { struct request *rq; BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); + if (!cfq_may_dispatch(cfqd, cfqq)) + return false; + /* * follow expired path, else get first next available */ @@ -1282,9 +2307,11 @@ static void cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq) if (!cfqd->active_cic) { struct cfq_io_context *cic = RQ_CIC(rq); - atomic_inc(&cic->ioc->refcount); + atomic_long_inc(&cic->ioc->refcount); cfqd->active_cic = cic; } + + return true; } /* @@ -1295,7 +2322,6 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) { struct cfq_data *cfqd = q->elevator->elevator_data; struct cfq_queue *cfqq; - unsigned int max_dispatch; if (!cfqd->busy_queues) return 0; @@ -1308,42 +2334,11 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) return 0; /* - * If this is an async queue and we have sync IO in flight, let it wait + * Dispatch a request from this cfqq, if it is allowed */ - if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq)) + if (!cfq_dispatch_request(cfqd, cfqq)) return 0; - max_dispatch = cfqd->cfq_quantum; - if (cfq_class_idle(cfqq)) - max_dispatch = 1; - - /* - * 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)) - return 0; - - /* - * We have other queues, don't allow more IO from this one - */ - if (cfqd->busy_queues > 1) - return 0; - - /* - * we are the only queue, allow up to 4 times of 'quantum' - */ - if (cfqq->dispatched >= 4 * max_dispatch) - return 0; - } - - /* - * Dispatch a request from this cfqq - */ - cfq_dispatch_request(cfqd, cfqq); cfqq->slice_dispatch++; cfq_clear_cfqq_must_dispatch(cfqq); @@ -1358,7 +2353,7 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) cfq_slice_expired(cfqd, 0); } - cfq_log(cfqd, "dispatched a request"); + cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); return 1; } @@ -1366,11 +2361,13 @@ 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); @@ -1380,14 +2377,19 @@ 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]); - BUG_ON(cfq_cfqq_on_rr(cfqq)); + cfqg = cfqq->cfqg; + orig_cfqg = cfqq->orig_cfqg; if (unlikely(cfqd->active_queue == cfqq)) { __cfq_slice_expired(cfqd, cfqq, 0); cfq_schedule_dispatch(cfqd); } + 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); } /* @@ -1423,7 +2425,7 @@ static void cfq_cic_free_rcu(struct rcu_head *head) cic = container_of(head, struct cfq_io_context, rcu_head); kmem_cache_free(cfq_ioc_pool, cic); - elv_ioc_count_dec(ioc_count); + elv_ioc_count_dec(cfq_ioc_count); if (ioc_gone) { /* @@ -1432,7 +2434,7 @@ static void cfq_cic_free_rcu(struct rcu_head *head) * complete ioc_gone and set it back to NULL */ spin_lock(&ioc_gone_lock); - if (ioc_gone && !elv_ioc_count_read(ioc_count)) { + if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) { complete(ioc_gone); ioc_gone = NULL; } @@ -1477,11 +2479,29 @@ static void cfq_free_io_context(struct io_context *ioc) static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) { + struct cfq_queue *__cfqq, *next; + if (unlikely(cfqq == cfqd->active_queue)) { __cfq_slice_expired(cfqd, cfqq, 0); cfq_schedule_dispatch(cfqd); } + /* + * If this queue was scheduled to merge with another queue, be + * sure to drop the reference taken on that queue (and others in + * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs. + */ + __cfqq = cfqq->new_cfqq; + while (__cfqq) { + if (__cfqq == cfqq) { + WARN(1, "cfqq->new_cfqq loop detected\n"); + break; + } + next = __cfqq->new_cfqq; + cfq_put_queue(__cfqq); + __cfqq = next; + } + cfq_put_queue(cfqq); } @@ -1558,7 +2578,7 @@ cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) INIT_HLIST_NODE(&cic->cic_list); cic->dtor = cfq_free_io_context; cic->exit = cfq_exit_io_context; - elv_ioc_count_inc(ioc_count); + elv_ioc_count_inc(cfq_ioc_count); } return cic; @@ -1642,68 +2662,110 @@ static void cfq_ioc_set_ioprio(struct io_context *ioc) ioc->ioprio_changed = 0; } +static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq, + pid_t pid, bool is_sync) +{ + 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); + + if (is_sync) { + if (!cfq_class_idle(cfqq)) + cfq_mark_cfqq_idle_window(cfqq); + cfq_mark_cfqq_sync(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, int is_sync, +cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, gfp_t gfp_mask) { struct cfq_queue *cfqq, *new_cfqq = NULL; struct cfq_io_context *cic; + struct cfq_group *cfqg; retry: + cfqg = cfq_get_cfqg(cfqd, 1); cic = cfq_cic_lookup(cfqd, ioc); /* cic always exists here */ cfqq = cic_to_cfqq(cic, is_sync); - if (!cfqq) { + /* + * Always try a new alloc if we fell back to the OOM cfqq + * originally, since it should just be a temporary situation. + */ + if (!cfqq || cfqq == &cfqd->oom_cfqq) { + cfqq = NULL; if (new_cfqq) { cfqq = new_cfqq; new_cfqq = NULL; } else if (gfp_mask & __GFP_WAIT) { - /* - * Inform the allocator of the fact that we will - * just repeat this allocation if it fails, to allow - * the allocator to do whatever it needs to attempt to - * free memory. - */ spin_unlock_irq(cfqd->queue->queue_lock); new_cfqq = kmem_cache_alloc_node(cfq_pool, - gfp_mask | __GFP_NOFAIL | __GFP_ZERO, + gfp_mask | __GFP_ZERO, cfqd->queue->node); spin_lock_irq(cfqd->queue->queue_lock); - goto retry; + if (new_cfqq) + goto retry; } else { cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask | __GFP_ZERO, cfqd->queue->node); - if (!cfqq) - goto out; } - 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_init_prio_data(cfqq, ioc); - - if (is_sync) { - if (!cfq_class_idle(cfqq)) - cfq_mark_cfqq_idle_window(cfqq); - cfq_mark_cfqq_sync(cfqq); - } - cfqq->pid = current->pid; - cfq_log_cfqq(cfqd, cfqq, "alloced"); + if (cfqq) { + cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); + cfq_init_prio_data(cfqq, ioc); + cfq_link_cfqq_cfqg(cfqq, cfqg); + cfq_log_cfqq(cfqd, cfqq, "alloced"); + } else + cfqq = &cfqd->oom_cfqq; } if (new_cfqq) kmem_cache_free(cfq_pool, new_cfqq); -out: - WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); return cfqq; } @@ -1723,7 +2785,7 @@ cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) } static struct cfq_queue * -cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc, +cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, gfp_t gfp_mask) { const int ioprio = task_ioprio(ioc); @@ -1736,11 +2798,8 @@ cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc, cfqq = *async_cfqq; } - if (!cfqq) { + if (!cfqq) cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); - if (!cfqq) - return NULL; - } /* * pin the queue now that it's allocated, scheduler exit will prune it @@ -1890,6 +2949,10 @@ 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); @@ -1910,33 +2973,46 @@ cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) } static void -cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic, +cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, struct request *rq) { sector_t sdist; u64 total; - if (!cic->last_request_pos) + if (!cfqq->last_request_pos) sdist = 0; - else if (cic->last_request_pos < blk_rq_pos(rq)) - sdist = blk_rq_pos(rq) - cic->last_request_pos; + else if (cfqq->last_request_pos < blk_rq_pos(rq)) + sdist = blk_rq_pos(rq) - cfqq->last_request_pos; else - sdist = cic->last_request_pos - blk_rq_pos(rq); + sdist = cfqq->last_request_pos - blk_rq_pos(rq); /* * Don't allow the seek distance to get too large from the * odd fragment, pagein, etc */ - if (cic->seek_samples <= 60) /* second&third seek */ - sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024); + if (cfqq->seek_samples <= 60) /* second&third seek */ + sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*1024); else - sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64); + sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*64); + + cfqq->seek_samples = (7*cfqq->seek_samples + 256) / 8; + cfqq->seek_total = (7*cfqq->seek_total + (u64)256*sdist) / 8; + total = cfqq->seek_total + (cfqq->seek_samples/2); + do_div(total, cfqq->seek_samples); + cfqq->seek_mean = (sector_t)total; - cic->seek_samples = (7*cic->seek_samples + 256) / 8; - cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8; - total = cic->seek_total + (cic->seek_samples/2); - do_div(total, cic->seek_samples); - cic->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; + } } /* @@ -1957,8 +3033,12 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); + if (cfqq->queued[0] + cfqq->queued[1] >= 4) + cfq_mark_cfqq_deep(cfqq); + if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || - (cfqd->hw_tag && CIC_SEEKY(cic))) + (!cfq_cfqq_deep(cfqq) && sample_valid(cfqq->seek_samples) + && CFQQ_SEEKY(cfqq))) enable_idle = 0; else if (sample_valid(cic->ttime_samples)) { if (cic->ttime_mean > cfqd->cfq_slice_idle) @@ -1980,7 +3060,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, * Check if new_cfqq should preempt the currently active queue. Return 0 for * no or if we aren't sure, a 1 will cause a preempt. */ -static int +static bool cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, struct request *rq) { @@ -1988,48 +3068,64 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, cfqq = cfqd->active_queue; if (!cfqq) - return 0; - - if (cfq_slice_used(cfqq)) - return 1; + return false; if (cfq_class_idle(new_cfqq)) - return 0; + return false; if (cfq_class_idle(cfqq)) - return 1; + 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 * not, let the sync request have priority. */ if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) - return 1; + 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. */ if (rq_is_meta(rq) && !cfqq->meta_pending) - return 1; + return true; /* * 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; + return true; if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) - return 0; + return false; /* * if this request is as-good as one we would expect from the * current cfqq, let it preempt */ - if (cfq_rq_close(cfqd, rq)) - return 1; + if (cfq_rq_close(cfqd, cfqq, rq, true)) + return true; - return 0; + return false; } /* @@ -2068,10 +3164,10 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, cfqq->meta_pending++; cfq_update_io_thinktime(cfqd, cic); - cfq_update_io_seektime(cfqd, cic, rq); + cfq_update_io_seektime(cfqd, cfqq, rq); cfq_update_idle_window(cfqd, cfqq, cic); - cic->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); + cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); if (cfqq == cfqd->active_queue) { /* @@ -2088,9 +3184,10 @@ 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); - __blk_run_queue(cfqd->queue); - } - cfq_mark_cfqq_must_dispatch(cfqq); + cfq_clear_cfqq_wait_request(cfqq); + __blk_run_queue(cfqd->queue); + } else + cfq_mark_cfqq_must_dispatch(cfqq); } } else if (cfq_should_preempt(cfqd, cfqq, rq)) { /* @@ -2112,9 +3209,9 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq) cfq_log_cfqq(cfqd, cfqq, "insert_request"); cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); - cfq_add_rq_rb(rq); - + rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]); list_add_tail(&rq->queuelist, &cfqq->fifo); + cfq_add_rq_rb(rq); cfq_rq_enqueued(cfqd, cfqq, rq); } @@ -2125,23 +3222,64 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq) */ static void cfq_update_hw_tag(struct cfq_data *cfqd) { - if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak) - cfqd->rq_in_driver_peak = cfqd->rq_in_driver; + struct cfq_queue *cfqq = cfqd->active_queue; + + if (rq_in_driver(cfqd) > cfqd->hw_tag_est_depth) + cfqd->hw_tag_est_depth = rq_in_driver(cfqd); + + if (cfqd->hw_tag == 1) + return; if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && - cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) + rq_in_driver(cfqd) <= CFQ_HW_QUEUE_MIN) + return; + + /* + * If active queue hasn't enough requests and can idle, cfq might not + * dispatch sufficient requests to hardware. Don't zero hw_tag in this + * case + */ + if (cfqq && cfq_cfqq_idle_window(cfqq) && + cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] < + CFQ_HW_QUEUE_MIN && rq_in_driver(cfqd) < CFQ_HW_QUEUE_MIN) return; if (cfqd->hw_tag_samples++ < 50) return; - if (cfqd->rq_in_driver_peak >= CFQ_HW_QUEUE_MIN) + if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN) cfqd->hw_tag = 1; else 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; - cfqd->hw_tag_samples = 0; - cfqd->rq_in_driver_peak = 0; + return false; } static void cfq_completed_request(struct request_queue *q, struct request *rq) @@ -2152,23 +3290,23 @@ 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); - WARN_ON(!cfqd->rq_in_driver); + WARN_ON(!cfqd->rq_in_driver[sync]); WARN_ON(!cfqq->dispatched); - cfqd->rq_in_driver--; + cfqd->rq_in_driver[sync]--; cfqq->dispatched--; if (cfq_cfqq_sync(cfqq)) cfqd->sync_flight--; - if (!cfq_class_idle(cfqq)) - cfqd->last_end_request = now; - - if (sync) + if (sync) { RQ_CIC(rq)->last_end_request = now; + if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) + cfqd->last_delayed_sync = now; + } /* * If this is the active queue, check if it needs to be expired, @@ -2181,21 +3319,42 @@ 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); + } + /* - * 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. + * Idling is not enabled on: + * - expired queues + * - idle-priority queues + * - async queues + * - queues with still some requests queued + * - when there is a close cooperator */ if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) cfq_slice_expired(cfqd, 1); - else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq, 1) && - sync && !rq_noidle(rq)) - cfq_arm_slice_timer(cfqd); + else if (sync && cfqq_empty && + !cfq_close_cooperator(cfqd, cfqq)) { + cfqd->noidle_tree_requires_idle |= !rq_noidle(rq); + /* + * Idling is enabled for SYNC_WORKLOAD. + * SYNC_NOIDLE_WORKLOAD idles at the end of the tree + * only if we processed at least one !rq_noidle request + */ + if (cfqd->serving_type == SYNC_WORKLOAD + || cfqd->noidle_tree_requires_idle + || cfqq->cfqg->nr_cfqq == 1) + cfq_arm_slice_timer(cfqd); + } } - if (!cfqd->rq_in_driver) + if (!rq_in_driver(cfqd)) cfq_schedule_dispatch(cfqd); } @@ -2216,19 +3375,16 @@ static void cfq_prio_boost(struct cfq_queue *cfqq) cfqq->ioprio = IOPRIO_NORM; } else { /* - * check if we need to unboost the queue + * unboost the queue (if needed) */ - if (cfqq->ioprio_class != cfqq->org_ioprio_class) - cfqq->ioprio_class = cfqq->org_ioprio_class; - if (cfqq->ioprio != cfqq->org_ioprio) - cfqq->ioprio = cfqq->org_ioprio; + cfqq->ioprio_class = cfqq->org_ioprio_class; + cfqq->ioprio = cfqq->org_ioprio; } } static inline int __cfq_may_queue(struct cfq_queue *cfqq) { - if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && - !cfq_cfqq_must_alloc_slice(cfqq)) { + if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { cfq_mark_cfqq_must_alloc_slice(cfqq); return ELV_MQUEUE_MUST; } @@ -2286,6 +3442,43 @@ static void cfq_put_request(struct request *rq) } } +static struct cfq_queue * +cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic, + struct cfq_queue *cfqq) +{ + cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq); + cic_set_cfqq(cic, cfqq->new_cfqq, 1); + cfq_mark_cfqq_coop(cfqq->new_cfqq); + cfq_put_queue(cfqq); + 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. + */ +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); + return cfqq; + } + + cic_set_cfqq(cic, NULL, 1); + cfq_put_queue(cfqq); + return NULL; +} /* * Allocate cfq data structures associated with this request. */ @@ -2295,7 +3488,7 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) struct cfq_data *cfqd = q->elevator->elevator_data; struct cfq_io_context *cic; const int rw = rq_data_dir(rq); - const int is_sync = rq_is_sync(rq); + const bool is_sync = rq_is_sync(rq); struct cfq_queue *cfqq; unsigned long flags; @@ -2308,18 +3501,33 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) if (!cic) goto queue_fail; +new_queue: cfqq = cic_to_cfqq(cic, is_sync); - if (!cfqq) { + if (!cfqq || cfqq == &cfqd->oom_cfqq) { cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); - - if (!cfqq) - goto queue_fail; - cic_set_cfqq(cic, cfqq, is_sync); + } else { + /* + * If the queue was seeky for too long, break it apart. + */ + if (cfq_cfqq_coop(cfqq) && should_split_cfqq(cfqq)) { + cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq"); + cfqq = split_cfqq(cic, cfqq); + if (!cfqq) + goto new_queue; + } + + /* + * Check to see if this queue is scheduled to merge with + * another, closely cooperating queue. The merging of + * queues happens here as it must be done in process context. + * The reference on new_cfqq was taken in merge_cfqqs. + */ + if (cfqq->new_cfqq) + cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq); } cfqq->allocated[rw]++; - cfq_clear_cfqq_must_alloc(cfqq); atomic_inc(&cfqq->ref); spin_unlock_irqrestore(q->queue_lock, flags); @@ -2391,6 +3599,11 @@ static void cfq_idle_slice_timer(unsigned long data) */ if (!RB_EMPTY_ROOT(&cfqq->sort_list)) goto out_kick; + + /* + * Queue depth flag is reset only when the idle didn't succeed + */ + cfq_clear_cfqq_deep(cfqq); } expire: cfq_slice_expired(cfqd, timed_out); @@ -2421,6 +3634,11 @@ 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; @@ -2442,25 +3660,49 @@ 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) { struct cfq_data *cfqd; - int i; + int i, j; + struct cfq_group *cfqg; + struct cfq_rb_root *st; cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); if (!cfqd) return NULL; - cfqd->service_tree = CFQ_RB_ROOT; + /* Init root service tree */ + cfqd->grp_service_tree = CFQ_RB_ROOT; + + /* Init root group */ + cfqg = &cfqd->root_group; + for_each_cfqg_st(cfqg, i, j, st) + *st = CFQ_RB_ROOT; + RB_CLEAR_NODE(&cfqg->rb_node); + + /* Give preference to root group over other groups */ + cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; +#ifdef CONFIG_CFQ_GROUP_IOSCHED + /* + * 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 * zeroed cfqd on alloc), but better be safe in case someone decides @@ -2469,6 +3711,15 @@ static void *cfq_init_queue(struct request_queue *q) for (i = 0; i < CFQ_PRIO_LISTS; i++) cfqd->prio_trees[i] = RB_ROOT; + /* + * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues. + * Grab a permanent reference to it, so that the normal code flow + * will not attempt to free it. + */ + cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0); + atomic_inc(&cfqd->oom_cfqq.ref); + cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); + INIT_LIST_HEAD(&cfqd->cic_list); cfqd->queue = q; @@ -2479,7 +3730,6 @@ static void *cfq_init_queue(struct request_queue *q) INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); - cfqd->last_end_request = jiffies; cfqd->cfq_quantum = cfq_quantum; cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; @@ -2489,8 +3739,15 @@ static void *cfq_init_queue(struct request_queue *q) cfqd->cfq_slice[1] = cfq_slice_sync; cfqd->cfq_slice_async_rq = cfq_slice_async_rq; cfqd->cfq_slice_idle = cfq_slice_idle; - cfqd->hw_tag = 1; - + cfqd->cfq_latency = 1; + cfqd->cfq_group_isolation = 0; + cfqd->hw_tag = -1; + /* + * 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; } @@ -2558,6 +3815,8 @@ SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); 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) \ @@ -2589,6 +3848,8 @@ STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); 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) \ @@ -2604,6 +3865,8 @@ static struct elv_fs_entry cfq_attrs[] = { CFQ_ATTR(slice_async), CFQ_ATTR(slice_async_rq), CFQ_ATTR(slice_idle), + CFQ_ATTR(low_latency), + CFQ_ATTR(group_isolation), __ATTR_NULL }; @@ -2633,6 +3896,17 @@ 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) { /* @@ -2647,6 +3921,7 @@ static int __init cfq_init(void) return -ENOMEM; elv_register(&iosched_cfq); + blkio_policy_register(&blkio_policy_cfq); return 0; } @@ -2654,6 +3929,7 @@ 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 */ @@ -2663,7 +3939,7 @@ static void __exit cfq_exit(void) * this also protects us from entering cfq_slab_kill() with * pending RCU callbacks */ - if (elv_ioc_count_read(ioc_count)) + if (elv_ioc_count_read(cfq_ioc_count)) wait_for_completion(&all_gone); cfq_slab_kill(); }