diff options
Diffstat (limited to 'ANDROID_3.4.5/block/cfq-iosched.c')
| -rw-r--r-- | ANDROID_3.4.5/block/cfq-iosched.c | 3936 |
1 files changed, 0 insertions, 3936 deletions
diff --git a/ANDROID_3.4.5/block/cfq-iosched.c b/ANDROID_3.4.5/block/cfq-iosched.c deleted file mode 100644 index 3c38536b..00000000 --- a/ANDROID_3.4.5/block/cfq-iosched.c +++ /dev/null @@ -1,3936 +0,0 @@ -/* - * CFQ, or complete fairness queueing, disk scheduler. - * - * Based on ideas from a previously unfinished io - * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. - * - * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> - */ -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/blkdev.h> -#include <linux/elevator.h> -#include <linux/jiffies.h> -#include <linux/rbtree.h> -#include <linux/ioprio.h> -#include <linux/blktrace_api.h> -#include "blk.h" -#include "cfq.h" - -/* - * tunables - */ -/* max queue in one round of service */ -static const int cfq_quantum = 8; -static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; -/* maximum backwards seek, in KiB */ -static const int cfq_back_max = 16 * 1024; -/* penalty of a backwards seek */ -static const int cfq_back_penalty = 2; -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 int cfq_group_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 - */ -#define CFQ_IDLE_DELAY (HZ / 5) - -/* - * below this threshold, we consider thinktime immediate - */ -#define CFQ_MIN_TT (2) - -#define CFQ_SLICE_SCALE (5) -#define CFQ_HW_QUEUE_MIN (5) -#define CFQ_SERVICE_SHIFT 12 - -#define CFQQ_SEEK_THR (sector_t)(8 * 100) -#define CFQQ_CLOSE_THR (sector_t)(8 * 1024) -#define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) -#define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) - -#define RQ_CIC(rq) icq_to_cic((rq)->elv.icq) -#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elv.priv[0]) -#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elv.priv[1]) - -static struct kmem_cache *cfq_pool; - -#define CFQ_PRIO_LISTS IOPRIO_BE_NR -#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) -#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) - -struct cfq_ttime { - unsigned long last_end_request; - - unsigned long ttime_total; - unsigned long ttime_samples; - unsigned long ttime_mean; -}; - -/* - * Most of our rbtree usage is for sorting with min extraction, so - * if we cache the leftmost node we don't have to walk down the tree - * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should - * move this into the elevator for the rq sorting as well. - */ -struct cfq_rb_root { - struct rb_root rb; - struct rb_node *left; - unsigned count; - unsigned total_weight; - u64 min_vdisktime; - struct cfq_ttime ttime; -}; -#define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \ - .ttime = {.last_end_request = jiffies,},} - -/* - * Per process-grouping structure - */ -struct cfq_queue { - /* reference count */ - int 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; - unsigned int slice_dispatch; - /* time when first request from queue completed and slice started. */ - unsigned long slice_start; - unsigned long slice_end; - long slice_resid; - - /* pending priority requests */ - int prio_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; - - pid_t pid; - - u32 seek_history; - sector_t last_request_pos; - - struct cfq_rb_root *service_tree; - struct cfq_queue *new_cfqq; - struct cfq_group *cfqg; - /* Number of sectors dispatched from queue in single 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, - CFQ_PRIO_NR, -}; - -/* - * 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; - unsigned int new_weight; - bool needs_update; - - /* number of cfqq currently on this group */ - int nr_cfqq; - - /* - * Per group busy queues average. Useful for workload slice calc. We - * create the array for each prio class but at run time it is used - * only for RT and BE class and slot for IDLE class remains unused. - * This is primarily done to avoid confusion and a gcc warning. - */ - unsigned int busy_queues_avg[CFQ_PRIO_NR]; - /* - * rr lists of queues with requests. We maintain service trees for - * RT and BE classes. These trees are subdivided in subclasses - * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE - * class there is no subclassification and all the cfq queues go on - * a single tree service_tree_idle. - * 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; - int ref; -#endif - /* number of requests that are on the dispatch list or inside driver */ - int dispatched; - struct cfq_ttime ttime; -}; - -struct cfq_io_cq { - struct io_cq icq; /* must be the first member */ - struct cfq_queue *cfqq[2]; - struct cfq_ttime ttime; -}; - -/* - * 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; - - /* - * The priority currently being served - */ - enum wl_prio_t serving_prio; - enum wl_type_t serving_type; - unsigned long workload_expires; - struct cfq_group *serving_group; - - /* - * Each priority tree is sorted by next_request position. These - * trees are used when determining if two or more queues are - * interleaving requests (see cfq_close_cooperator). - */ - struct rb_root prio_trees[CFQ_PRIO_LISTS]; - - unsigned int busy_queues; - unsigned int busy_sync_queues; - - int rq_in_driver; - int rq_in_flight[2]; - - /* - * queue-depth detection - */ - int rq_queued; - int hw_tag; - /* - * 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 - */ - struct timer_list idle_slice_timer; - struct work_struct unplug_work; - - struct cfq_queue *active_queue; - struct cfq_io_cq *active_cic; - - /* - * async queue for each priority case - */ - struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; - struct cfq_queue *async_idle_cfqq; - - sector_t last_position; - - /* - * tunables, see top of file - */ - unsigned int cfq_quantum; - unsigned int cfq_fifo_expire[2]; - unsigned int cfq_back_penalty; - unsigned int cfq_back_max; - unsigned int cfq_slice[2]; - unsigned int cfq_slice_async_rq; - unsigned int cfq_slice_idle; - unsigned int cfq_group_idle; - unsigned int cfq_latency; - unsigned int cfq_target_latency; - - /* - * Fallback dummy cfqq for extreme OOM conditions - */ - struct cfq_queue oom_cfqq; - - unsigned long last_delayed_sync; - - /* List of cfq groups being managed on this device*/ - struct hlist_head cfqg_list; - - /* Number of groups which are on blkcg->blkg_list */ - unsigned int nr_blkcg_linked_grps; -}; - -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) -{ - 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_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, /* 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) \ -static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ -{ \ - (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ -} \ -static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ -{ \ - (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ -} \ -static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ -{ \ - return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ -} - -CFQ_CFQQ_FNS(on_rr); -CFQ_CFQQ_FNS(wait_request); -CFQ_CFQQ_FNS(must_dispatch); -CFQ_CFQQ_FNS(must_alloc_slice); -CFQ_CFQQ_FNS(fifo_expire); -CFQ_CFQQ_FNS(idle_window); -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_CFQ_GROUP_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 bool cfq_io_thinktime_big(struct cfq_data *cfqd, - struct cfq_ttime *ttime, bool group_idle) -{ - unsigned long slice; - if (!sample_valid(ttime->ttime_samples)) - return false; - if (group_idle) - slice = cfqd->cfq_group_idle; - else - slice = cfqd->cfq_slice_idle; - return ttime->ttime_mean > slice; -} - -static inline bool iops_mode(struct cfq_data *cfqd) -{ - /* - * If we are not idling on queues and it is a NCQ drive, parallel - * execution of requests is on and measuring time is not possible - * in most of the cases until and unless we drive shallower queue - * depths and that becomes a performance bottleneck. In such cases - * switch to start providing fairness in terms of number of IOs. - */ - if (!cfqd->cfq_slice_idle && cfqd->hw_tag) - return true; - else - return false; -} - -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 *, bool, - struct io_context *, gfp_t); - -static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq) -{ - /* cic->icq is the first member, %NULL will convert to %NULL */ - return container_of(icq, struct cfq_io_cq, icq); -} - -static inline struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *cfqd, - struct io_context *ioc) -{ - if (ioc) - return icq_to_cic(ioc_lookup_icq(ioc, cfqd->queue)); - return NULL; -} - -static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync) -{ - return cic->cfqq[is_sync]; -} - -static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq, - bool is_sync) -{ - cic->cfqq[is_sync] = cfqq; -} - -static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic) -{ - return cic->icq.q->elevator->elevator_data; -} - -/* - * 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 bool cfq_bio_sync(struct bio *bio) -{ - return bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC); -} - -/* - * scheduler run of queue, if there are requests pending and no one in the - * driver that will restart queueing - */ -static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) -{ - if (cfqd->busy_queues) { - cfq_log(cfqd, "schedule dispatch"); - kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); - } -} - -/* - * Scale schedule slice based on io priority. Use the sync time slice only - * 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, bool sync, - unsigned short prio) -{ - const int base_slice = cfqd->cfq_slice[sync]; - - WARN_ON(prio >= IOPRIO_BE_NR); - - return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); -} - -static inline int -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) -{ - struct cfq_group *cfqg; - - if (st->left) { - cfqg = rb_entry_cfqg(st->left); - st->min_vdisktime = max_vdisktime(st->min_vdisktime, - cfqg->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 cfqd->cfq_target_latency * cfqg->weight / st->total_weight; -} - -static inline unsigned -cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - 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); - } - } - return slice; -} - -static inline void -cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - unsigned slice = cfq_scaled_cfqq_slice(cfqd, 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); -} - -/* - * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end - * isn't valid until the first request from the dispatch is activated - * and the slice time set. - */ -static inline bool cfq_slice_used(struct cfq_queue *cfqq) -{ - if (cfq_cfqq_slice_new(cfqq)) - return false; - if (time_before(jiffies, cfqq->slice_end)) - return false; - - return true; -} - -/* - * Lifted from AS - choose which of rq1 and rq2 that is best served now. - * We choose the request that is closest to the head right now. Distance - * 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, sector_t last) -{ - 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 */ - unsigned wrap = 0; /* bit mask: requests behind the disk head? */ - - if (rq1 == NULL || rq1 == rq2) - return rq2; - if (rq2 == NULL) - return rq1; - - if (rq_is_sync(rq1) != rq_is_sync(rq2)) - return rq_is_sync(rq1) ? rq1 : rq2; - - if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO) - return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2; - - s1 = blk_rq_pos(rq1); - s2 = blk_rq_pos(rq2); - - /* - * by definition, 1KiB is 2 sectors - */ - back_max = cfqd->cfq_back_max * 2; - - /* - * Strict one way elevator _except_ in the case where we allow - * short backward seeks which are biased as twice the cost of a - * similar forward seek. - */ - if (s1 >= last) - d1 = s1 - last; - else if (s1 + back_max >= last) - d1 = (last - s1) * cfqd->cfq_back_penalty; - else - wrap |= CFQ_RQ1_WRAP; - - if (s2 >= last) - d2 = s2 - last; - else if (s2 + back_max >= last) - d2 = (last - s2) * cfqd->cfq_back_penalty; - else - wrap |= CFQ_RQ2_WRAP; - - /* Found required data */ - - /* - * By doing switch() on the bit mask "wrap" we avoid having to - * check two variables for all permutations: --> faster! - */ - switch (wrap) { - case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ - if (d1 < d2) - return rq1; - else if (d2 < d1) - return rq2; - else { - if (s1 >= s2) - return rq1; - else - return rq2; - } - - case CFQ_RQ2_WRAP: - return rq1; - case CFQ_RQ1_WRAP: - return rq2; - case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ - default: - /* - * Since both rqs are wrapped, - * start with the one that's further behind head - * (--> only *one* back seek required), - * since back seek takes more time than forward. - */ - if (s1 <= s2) - return rq1; - else - return rq2; - } -} - -/* - * The below is leftmost cache rbtree addon - */ -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); - - if (root->left) - return rb_entry(root->left, struct cfq_queue, rb_node); - - 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); - RB_CLEAR_NODE(n); -} - -static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) -{ - if (root->left == n) - root->left = NULL; - rb_erase_init(n, &root->rb); - --root->count; -} - -/* - * would be nice to take fifo expire time into account as well - */ -static struct request * -cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct request *last) -{ - struct rb_node *rbnext = rb_next(&last->rb_node); - struct rb_node *rbprev = rb_prev(&last->rb_node); - struct request *next = NULL, *prev = NULL; - - BUG_ON(RB_EMPTY_NODE(&last->rb_node)); - - if (rbprev) - prev = rb_entry_rq(rbprev); - - if (rbnext) - next = rb_entry_rq(rbnext); - else { - rbnext = rb_first(&cfqq->sort_list); - if (rbnext && rbnext != &last->rb_node) - next = rb_entry_rq(rbnext); - } - - return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last)); -} - -static unsigned long cfq_slice_offset(struct cfq_data *cfqd, - struct cfq_queue *cfqq) -{ - /* - * just an approximation, should be ok. - */ - 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_update_group_weight(struct cfq_group *cfqg) -{ - BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); - if (cfqg->needs_update) { - cfqg->weight = cfqg->new_weight; - cfqg->needs_update = false; - } -} - -static void -cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) -{ - BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node)); - - cfq_update_group_weight(cfqg); - __cfq_group_service_tree_add(st, cfqg); - st->total_weight += cfqg->weight; -} - -static void -cfq_group_notify_queue_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 (!RB_EMPTY_NODE(&cfqg->rb_node)) - 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 continuously 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); -} - -static void -cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg) -{ - st->total_weight -= cfqg->weight; - if (!RB_EMPTY_NODE(&cfqg->rb_node)) - cfq_rb_erase(&cfqg->rb_node, st); -} - -static void -cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg) -{ - struct cfq_rb_root *st = &cfqd->grp_service_tree; - - 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"); - cfq_group_service_tree_del(st, cfqg); - cfqg->saved_workload_slice = 0; - cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1); -} - -static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq, - unsigned int *unaccounted_time) -{ - 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) { - *unaccounted_time = slice_used - cfqq->allocated_slice; - slice_used = cfqq->allocated_slice; - } - if (time_after(cfqq->slice_start, cfqq->dispatch_start)) - *unaccounted_time += cfqq->slice_start - - cfqq->dispatch_start; - } - - 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, unaccounted_sl = 0; - 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 = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl); - - if (iops_mode(cfqd)) - charge = cfqq->slice_dispatch; - else if (!cfq_cfqq_sync(cfqq) && !nr_sync) - charge = cfqq->allocated_slice; - - /* Can't update vdisktime while group is on service tree */ - cfq_group_service_tree_del(st, cfqg); - cfqg->vdisktime += cfq_scale_slice(charge, cfqg); - /* If a new weight was requested, update now, off tree */ - 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); - cfq_log_cfqq(cfqq->cfqd, cfqq, - "sl_used=%u disp=%u charge=%u iops=%u sect=%lu", - used_sl, cfqq->slice_dispatch, charge, - iops_mode(cfqd), cfqq->nr_sectors); - cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl, - unaccounted_sl); - cfq_blkiocg_set_start_empty_time(&cfqg->blkg); -} - -#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; -} - -static void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg, - unsigned int weight) -{ - struct cfq_group *cfqg = cfqg_of_blkg(blkg); - cfqg->new_weight = weight; - cfqg->needs_update = true; -} - -static void cfq_init_add_cfqg_lists(struct cfq_data *cfqd, - struct cfq_group *cfqg, struct blkio_cgroup *blkcg) -{ - struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; - unsigned int major, minor; - - /* - * Add group onto cgroup list. It might happen that bdi->dev is - * not initialized yet. Initialize this new group without major - * and minor info and this info will be filled in once a new thread - * comes for IO. - */ - if (bdi->dev) { - sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); - cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, - (void *)cfqd, MKDEV(major, minor)); - } else - cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, - (void *)cfqd, 0); - - cfqd->nr_blkcg_linked_grps++; - cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev); - - /* Add group on cfqd list */ - hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); -} - -/* - * Should be called from sleepable context. No request queue lock as per - * cpu stats are allocated dynamically and alloc_percpu needs to be called - * from sleepable context. - */ -static struct cfq_group * cfq_alloc_cfqg(struct cfq_data *cfqd) -{ - struct cfq_group *cfqg = NULL; - int i, j, ret; - struct cfq_rb_root *st; - - cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node); - if (!cfqg) - return NULL; - - for_each_cfqg_st(cfqg, i, j, st) - *st = CFQ_RB_ROOT; - RB_CLEAR_NODE(&cfqg->rb_node); - - cfqg->ttime.last_end_request = jiffies; - - /* - * 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. - */ - cfqg->ref = 1; - - ret = blkio_alloc_blkg_stats(&cfqg->blkg); - if (ret) { - kfree(cfqg); - return NULL; - } - - return cfqg; -} - -static struct cfq_group * -cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg) -{ - struct cfq_group *cfqg = NULL; - void *key = cfqd; - struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info; - unsigned int major, minor; - - /* - * This is the common case when there are no blkio cgroups. - * Avoid lookup in this case - */ - if (blkcg == &blkio_root_cgroup) - cfqg = &cfqd->root_group; - else - cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key)); - - if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) { - sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor); - cfqg->blkg.dev = MKDEV(major, minor); - } - - return cfqg; -} - -/* - * Search for the cfq group current task belongs to. request_queue lock must - * be held. - */ -static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd) -{ - struct blkio_cgroup *blkcg; - struct cfq_group *cfqg = NULL, *__cfqg = NULL; - struct request_queue *q = cfqd->queue; - - rcu_read_lock(); - blkcg = task_blkio_cgroup(current); - cfqg = cfq_find_cfqg(cfqd, blkcg); - if (cfqg) { - rcu_read_unlock(); - return cfqg; - } - - /* - * Need to allocate a group. Allocation of group also needs allocation - * of per cpu stats which in-turn takes a mutex() and can block. Hence - * we need to drop rcu lock and queue_lock before we call alloc. - * - * Not taking any queue reference here and assuming that queue is - * around by the time we return. CFQ queue allocation code does - * the same. It might be racy though. - */ - - rcu_read_unlock(); - spin_unlock_irq(q->queue_lock); - - cfqg = cfq_alloc_cfqg(cfqd); - - spin_lock_irq(q->queue_lock); - - rcu_read_lock(); - blkcg = task_blkio_cgroup(current); - - /* - * If some other thread already allocated the group while we were - * not holding queue lock, free up the group - */ - __cfqg = cfq_find_cfqg(cfqd, blkcg); - - if (__cfqg) { - kfree(cfqg); - rcu_read_unlock(); - return __cfqg; - } - - if (!cfqg) - cfqg = &cfqd->root_group; - - cfq_init_add_cfqg_lists(cfqd, cfqg, blkcg); - rcu_read_unlock(); - return cfqg; -} - -static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) -{ - cfqg->ref++; - 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 */ - cfqq->cfqg->ref++; -} - -static void cfq_put_cfqg(struct cfq_group *cfqg) -{ - struct cfq_rb_root *st; - int i, j; - - BUG_ON(cfqg->ref <= 0); - cfqg->ref--; - if (cfqg->ref) - return; - for_each_cfqg_st(cfqg, i, j, st) - BUG_ON(!RB_EMPTY_ROOT(&st->rb)); - free_percpu(cfqg->blkg.stats_cpu); - 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); - - BUG_ON(cfqd->nr_blkcg_linked_grps <= 0); - cfqd->nr_blkcg_linked_grps--; - - /* - * 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 (!cfq_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. - */ -static 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) -{ - return &cfqd->root_group; -} - -static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg) -{ - return cfqg; -} - -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_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, - 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; - - 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(&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; - cfqq->slice_resid = 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 && - cfqq->service_tree == service_tree) - return; - - cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree); - cfqq->service_tree = NULL; - } - - left = 1; - parent = NULL; - cfqq->service_tree = service_tree; - p = &service_tree->rb.rb_node; - while (*p) { - struct rb_node **n; - - parent = *p; - __cfqq = rb_entry(parent, struct cfq_queue, rb_node); - - /* - * sort by key, that represents service time. - */ - if (time_before(rb_key, __cfqq->rb_key)) - n = &(*p)->rb_left; - else { - n = &(*p)->rb_right; - left = 0; - } - - p = n; - } - - if (left) - 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, &service_tree->rb); - service_tree->count++; - if (add_front || !new_cfqq) - return; - cfq_group_notify_queue_add(cfqd, cfqq->cfqg); -} - -static struct cfq_queue * -cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root, - sector_t sector, struct rb_node **ret_parent, - struct rb_node ***rb_link) -{ - struct rb_node **p, *parent; - struct cfq_queue *cfqq = NULL; - - parent = NULL; - p = &root->rb_node; - while (*p) { - struct rb_node **n; - - parent = *p; - cfqq = rb_entry(parent, struct cfq_queue, p_node); - - /* - * Sort strictly based on sector. Smallest to the left, - * largest to the right. - */ - if (sector > blk_rq_pos(cfqq->next_rq)) - n = &(*p)->rb_right; - else if (sector < blk_rq_pos(cfqq->next_rq)) - n = &(*p)->rb_left; - else - break; - p = n; - cfqq = NULL; - } - - *ret_parent = parent; - if (rb_link) - *rb_link = p; - return cfqq; -} - -static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - struct rb_node **p, *parent; - struct cfq_queue *__cfqq; - - if (cfqq->p_root) { - rb_erase(&cfqq->p_node, cfqq->p_root); - cfqq->p_root = NULL; - } - - if (cfq_class_idle(cfqq)) - return; - if (!cfqq->next_rq) - return; - - cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio]; - __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root, - blk_rq_pos(cfqq->next_rq), &parent, &p); - if (!__cfqq) { - rb_link_node(&cfqq->p_node, parent, p); - rb_insert_color(&cfqq->p_node, cfqq->p_root); - } else - cfqq->p_root = NULL; -} - -/* - * Update cfqq's position in the service tree. - */ -static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - /* - * Resorting requires the cfqq to be on the RR list already. - */ - if (cfq_cfqq_on_rr(cfqq)) { - cfq_service_tree_add(cfqd, cfqq, 0); - cfq_prio_tree_add(cfqd, cfqq); - } -} - -/* - * add to busy list of queues for service, trying to be fair in ordering - * the pending list according to last request service - */ -static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); - BUG_ON(cfq_cfqq_on_rr(cfqq)); - cfq_mark_cfqq_on_rr(cfqq); - cfqd->busy_queues++; - if (cfq_cfqq_sync(cfqq)) - cfqd->busy_sync_queues++; - - cfq_resort_rr_list(cfqd, cfqq); -} - -/* - * Called when the cfqq no longer has requests pending, remove it from - * the service tree. - */ -static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); - 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, 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_notify_queue_del(cfqd, cfqq->cfqg); - BUG_ON(!cfqd->busy_queues); - cfqd->busy_queues--; - if (cfq_cfqq_sync(cfqq)) - cfqd->busy_sync_queues--; -} - -/* - * rb tree support functions - */ -static void cfq_del_rq_rb(struct request *rq) -{ - struct cfq_queue *cfqq = RQ_CFQQ(rq); - const int sync = rq_is_sync(rq); - - BUG_ON(!cfqq->queued[sync]); - cfqq->queued[sync]--; - - elv_rb_del(&cfqq->sort_list, rq); - - 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) -{ - struct cfq_queue *cfqq = RQ_CFQQ(rq); - struct cfq_data *cfqd = cfqq->cfqd; - struct request *prev; - - cfqq->queued[rq_is_sync(rq)]++; - - elv_rb_add(&cfqq->sort_list, rq); - - if (!cfq_cfqq_on_rr(cfqq)) - cfq_add_cfqq_rr(cfqd, cfqq); - - /* - * 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, cfqd->last_position); - - /* - * adjust priority tree position, if ->next_rq changes - */ - if (prev != cfqq->next_rq) - cfq_prio_tree_add(cfqd, cfqq); - - BUG_ON(!cfqq->next_rq); -} - -static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) -{ - elv_rb_del(&cfqq->sort_list, rq); - cfqq->queued[rq_is_sync(rq)]--; - cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, - rq_data_dir(rq), rq_is_sync(rq)); - cfq_add_rq_rb(rq); - cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, - &cfqq->cfqd->serving_group->blkg, rq_data_dir(rq), - rq_is_sync(rq)); -} - -static struct request * -cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) -{ - struct task_struct *tsk = current; - struct cfq_io_cq *cic; - struct cfq_queue *cfqq; - - cic = cfq_cic_lookup(cfqd, tsk->io_context); - if (!cic) - return NULL; - - cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); - if (cfqq) { - sector_t sector = bio->bi_sector + bio_sectors(bio); - - return elv_rb_find(&cfqq->sort_list, sector); - } - - return NULL; -} - -static void cfq_activate_request(struct request_queue *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - cfqd->rq_in_driver++; - cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", - cfqd->rq_in_driver); - - cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq); -} - -static void cfq_deactivate_request(struct request_queue *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - WARN_ON(!cfqd->rq_in_driver); - cfqd->rq_in_driver--; - cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", - cfqd->rq_in_driver); -} - -static void cfq_remove_request(struct request *rq) -{ - struct cfq_queue *cfqq = RQ_CFQQ(rq); - - if (cfqq->next_rq == rq) - cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); - - list_del_init(&rq->queuelist); - cfq_del_rq_rb(rq); - - cfqq->cfqd->rq_queued--; - cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, - rq_data_dir(rq), rq_is_sync(rq)); - if (rq->cmd_flags & REQ_PRIO) { - WARN_ON(!cfqq->prio_pending); - cfqq->prio_pending--; - } -} - -static int cfq_merge(struct request_queue *q, struct request **req, - struct bio *bio) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct request *__rq; - - __rq = cfq_find_rq_fmerge(cfqd, bio); - if (__rq && elv_rq_merge_ok(__rq, bio)) { - *req = __rq; - return ELEVATOR_FRONT_MERGE; - } - - return ELEVATOR_NO_MERGE; -} - -static void cfq_merged_request(struct request_queue *q, struct request *req, - int type) -{ - if (type == ELEVATOR_FRONT_MERGE) { - struct cfq_queue *cfqq = RQ_CFQQ(req); - - cfq_reposition_rq_rb(cfqq, req); - } -} - -static void cfq_bio_merged(struct request_queue *q, struct request *req, - struct bio *bio) -{ - cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg, - bio_data_dir(bio), cfq_bio_sync(bio)); -} - -static void -cfq_merged_requests(struct request_queue *q, struct request *rq, - struct request *next) -{ - struct cfq_queue *cfqq = RQ_CFQQ(rq); - struct cfq_data *cfqd = q->elevator->elevator_data; - - /* - * reposition in fifo if next is older than rq - */ - if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && - 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); - cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg, - rq_data_dir(next), rq_is_sync(next)); - - cfqq = RQ_CFQQ(next); - /* - * all requests of this queue are merged to other queues, delete it - * from the service tree. If it's the active_queue, - * cfq_dispatch_requests() will choose to expire it or do idle - */ - if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list) && - cfqq != cfqd->active_queue) - cfq_del_cfqq_rr(cfqd, cfqq); -} - -static int cfq_allow_merge(struct request_queue *q, struct request *rq, - struct bio *bio) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_io_cq *cic; - struct cfq_queue *cfqq; - - /* - * Disallow merge of a sync bio into an async request. - */ - if (cfq_bio_sync(bio) && !rq_is_sync(rq)) - return false; - - /* - * Lookup the cfqq that this bio will be queued with and allow - * merge only if rq is queued there. - */ - cic = cfq_cic_lookup(cfqd, current->io_context); - if (!cic) - return false; - - cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); - return cfqq == RQ_CFQQ(rq); -} - -static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - del_timer(&cfqd->idle_slice_timer); - cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); -} - -static void __cfq_set_active_queue(struct cfq_data *cfqd, - struct cfq_queue *cfqq) -{ - if (cfqq) { - cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d", - cfqd->serving_prio, cfqd->serving_type); - cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg); - 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); - cfq_clear_cfqq_must_alloc_slice(cfqq); - cfq_clear_cfqq_fifo_expire(cfqq); - cfq_mark_cfqq_slice_new(cfqq); - - cfq_del_timer(cfqd, cfqq); - } - - cfqd->active_queue = cfqq; -} - -/* - * current cfqq expired its slice (or was too idle), select new one - */ -static void -__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, - bool timed_out) -{ - cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); - - if (cfq_cfqq_wait_request(cfqq)) - cfq_del_timer(cfqd, cfqq); - - 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 - */ - if (timed_out) { - if (cfq_cfqq_slice_new(cfqq)) - cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq); - else - cfqq->slice_resid = cfqq->slice_end - jiffies; - 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 (cfqd->active_cic) { - put_io_context(cfqd->active_cic->icq.ioc); - cfqd->active_cic = NULL; - } -} - -static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out) -{ - struct cfq_queue *cfqq = cfqd->active_queue; - - if (cfqq) - __cfq_slice_expired(cfqd, cfqq, timed_out); -} - -/* - * Get next queue for service. Unless we have a queue preemption, - * we'll simply select the first cfqq in the service tree. - */ -static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) -{ - struct cfq_rb_root *service_tree = - service_tree_for(cfqd->serving_group, cfqd->serving_prio, - cfqd->serving_type); - - if (!cfqd->rq_queued) - return NULL; - - /* 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; -} - -/* - * Get and set a new active queue for service. - */ -static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, - struct cfq_queue *cfqq) -{ - if (!cfqq) - cfqq = cfq_get_next_queue(cfqd); - - __cfq_set_active_queue(cfqd, cfqq); - return cfqq; -} - -static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, - struct request *rq) -{ - if (blk_rq_pos(rq) >= cfqd->last_position) - return blk_rq_pos(rq) - cfqd->last_position; - else - return cfqd->last_position - blk_rq_pos(rq); -} - -static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct request *rq) -{ - return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR; -} - -static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, - struct cfq_queue *cur_cfqq) -{ - struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio]; - struct rb_node *parent, *node; - struct cfq_queue *__cfqq; - sector_t sector = cfqd->last_position; - - if (RB_EMPTY_ROOT(root)) - return NULL; - - /* - * First, if we find a request starting at the end of the last - * request, choose it. - */ - __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL); - if (__cfqq) - return __cfqq; - - /* - * If the exact sector wasn't found, the parent of the NULL leaf - * will contain the closest sector. - */ - __cfqq = rb_entry(parent, struct cfq_queue, p_node); - if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) - return __cfqq; - - if (blk_rq_pos(__cfqq->next_rq) < sector) - node = rb_next(&__cfqq->p_node); - else - node = rb_prev(&__cfqq->p_node); - if (!node) - return NULL; - - __cfqq = rb_entry(node, struct cfq_queue, p_node); - if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq)) - return __cfqq; - - return NULL; -} - -/* - * cfqd - obvious - * cur_cfqq - passed in so that we don't decide that the current queue is - * closely cooperating with itself. - * - * So, basically we're assuming that that cur_cfqq has dispatched at least - * one request, and that cfqd->last_position reflects a position on the disk - * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid - * assumption. - */ -static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, - struct cfq_queue *cur_cfqq) -{ - struct cfq_queue *cfqq; - - if (cfq_class_idle(cur_cfqq)) - return NULL; - if (!cfq_cfqq_sync(cur_cfqq)) - return NULL; - if (CFQQ_SEEKY(cur_cfqq)) - 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. - */ - cfqq = cfqq_close(cfqd, cur_cfqq); - 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. - */ - 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; - - 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); - - if (!cfqd->cfq_slice_idle) - return false; - - /* 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. - */ - if (service_tree->count == 1 && cfq_cfqq_sync(cfqq) && - !cfq_io_thinktime_big(cfqd, &service_tree->ttime, false)) - return true; - cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d", - service_tree->count); - return false; -} - -static void cfq_arm_slice_timer(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq = cfqd->active_queue; - struct cfq_io_cq *cic; - unsigned long sl, group_idle = 0; - - /* - * SSD device without seek penalty, disable idling. But only do so - * for devices that support queuing, otherwise we still have a problem - * with sync vs async workloads. - */ - if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) - return; - - WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); - WARN_ON(cfq_cfqq_slice_new(cfqq)); - - /* - * idle is disabled, either manually or by past process history - */ - if (!cfq_should_idle(cfqd, cfqq)) { - /* no queue idling. Check for group idling */ - if (cfqd->cfq_group_idle) - group_idle = cfqd->cfq_group_idle; - else - return; - } - - /* - * still active requests from this queue, don't idle - */ - if (cfqq->dispatched) - return; - - /* - * task has exited, don't wait - */ - cic = cfqd->active_cic; - if (!cic || !atomic_read(&cic->icq.ioc->nr_tasks)) - return; - - /* - * 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.ttime_samples) && - (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) { - cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%lu", - cic->ttime.ttime_mean); - return; - } - - /* There are other queues in the group, don't do group idle */ - if (group_idle && cfqq->cfqg->nr_cfqq > 1) - return; - - cfq_mark_cfqq_wait_request(cfqq); - - if (group_idle) - sl = cfqd->cfq_group_idle; - else - sl = cfqd->cfq_slice_idle; - - mod_timer(&cfqd->idle_slice_timer, jiffies + sl); - cfq_blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg); - cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl, - group_idle ? 1 : 0); -} - -/* - * Move request from internal lists to the request queue dispatch list. - */ -static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq = RQ_CFQQ(rq); - - cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); - - cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq); - cfq_remove_request(rq); - cfqq->dispatched++; - (RQ_CFQG(rq))->dispatched++; - elv_dispatch_sort(q, rq); - - cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++; - cfqq->nr_sectors += blk_rq_sectors(rq); - cfq_blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq), - rq_data_dir(rq), rq_is_sync(rq)); -} - -/* - * return expired entry, or NULL to just start from scratch in rbtree - */ -static struct request *cfq_check_fifo(struct cfq_queue *cfqq) -{ - struct request *rq = NULL; - - if (cfq_cfqq_fifo_expire(cfqq)) - return NULL; - - cfq_mark_cfqq_fifo_expire(cfqq); - - if (list_empty(&cfqq->fifo)) - return NULL; - - rq = rq_entry_fifo(cfqq->fifo.next); - if (time_before(jiffies, rq_fifo_time(rq))) - rq = NULL; - - 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) -{ - const int base_rq = cfqd->cfq_slice_async_rq; - - WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); - - return 2 * base_rq * (IOPRIO_BE_NR - 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 = 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; - - /* - * If there are no process references on the new_cfqq, then it is - * unsafe to follow the ->new_cfqq chain as other cfqq's in the - * chain may have dropped their last reference (not just their - * last process reference). - */ - if (!cfqq_process_refs(new_cfqq)) - return; - - /* 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); - new_process_refs = cfqq_process_refs(new_cfqq); - /* - * If the process for the cfqq has gone away, there is no - * sense in merging the queues. - */ - if (process_refs == 0 || new_process_refs == 0) - return; - - /* - * Merge in the direction of the lesser amount of work. - */ - if (new_process_refs >= process_refs) { - cfqq->new_cfqq = new_cfqq; - new_cfqq->ref += process_refs; - } else { - new_cfqq->new_cfqq = cfqq; - cfqq->ref += new_process_refs; - } -} - -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; - enum wl_prio_t original_prio = cfqd->serving_prio; - - /* 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; - } - - if (original_prio != cfqd->serving_prio) - goto new_workload; - - /* - * 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; - -new_workload: - /* 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 = cfqd->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); - cfq_log(cfqd, "workload slice:%d", slice); - cfqd->workload_expires = jiffies + slice; -} - -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); - update_min_vdisktime(st); - return cfqg; -} - -static void cfq_choose_cfqg(struct cfq_data *cfqd) -{ - struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd); - - cfqd->serving_group = cfqg; - - /* 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); -} - -/* - * Select a queue for service. If we have a current active queue, - * check whether to continue servicing it, or retrieve and set a new one. - */ -static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq, *new_cfqq = NULL; - - cfqq = cfqd->active_queue; - if (!cfqq) - goto new_queue; - - if (!cfqd->rq_queued) - return NULL; - - /* - * We were waiting for group to get backlogged. Expire the queue - */ - 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 check_group_idle; - } - - /* - * The active queue has requests and isn't expired, allow it to - * dispatch. - */ - if (!RB_EMPTY_ROOT(&cfqq->sort_list)) - goto keep_queue; - - /* - * If another queue has a request waiting within our mean seek - * distance, let it run. The expire code will check for close - * cooperators and put the close queue at the front of the service - * tree. If possible, merge the expiring queue with the 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 - * flight or is idling for a new request, allow either of these - * conditions to happen (or time out) before selecting a new queue. - */ - if (timer_pending(&cfqd->idle_slice_timer)) { - cfqq = NULL; - goto keep_queue; - } - - /* - * This is a deep seek queue, but the device is much faster than - * the queue can deliver, don't idle - **/ - if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) && - (cfq_cfqq_slice_new(cfqq) || - (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) { - cfq_clear_cfqq_deep(cfqq); - cfq_clear_cfqq_idle_window(cfqq); - } - - if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) { - cfqq = NULL; - goto keep_queue; - } - - /* - * If group idle is enabled and there are requests dispatched from - * this group, wait for requests to complete. - */ -check_group_idle: - if (cfqd->cfq_group_idle && cfqq->cfqg->nr_cfqq == 1 && - cfqq->cfqg->dispatched && - !cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) { - cfqq = NULL; - goto keep_queue; - } - -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; -} - -static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) -{ - int dispatched = 0; - - while (cfqq->next_rq) { - cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); - dispatched++; - } - - 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; -} - -/* - * Drain our current requests. Used for barriers and when switching - * io schedulers on-the-fly. - */ -static int cfq_forced_dispatch(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq; - int dispatched = 0; - - /* Expire the timeslice of the current active queue first */ - cfq_slice_expired(cfqd, 0); - while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) { - __cfq_set_active_queue(cfqd, cfqq); - dispatched += __cfq_forced_dispatch_cfqq(cfqq); - } - - BUG_ON(cfqd->busy_queues); - - cfq_log(cfqd, "forced_dispatch=%d", dispatched); - return dispatched; -} - -static inline bool cfq_slice_used_soon(struct cfq_data *cfqd, - struct cfq_queue *cfqq) -{ - /* the queue hasn't finished any request, can't estimate */ - if (cfq_cfqq_slice_new(cfqq)) - return true; - if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched, - cfqq->slice_end)) - return true; - - return false; -} - -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_flight[BLK_RW_ASYNC]) - return false; - - /* - * If this is an async queue and we have sync IO in flight, let it wait - */ - if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq)) - return false; - - max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1); - if (cfq_class_idle(cfqq)) - max_dispatch = 1; - - /* - * Does this cfqq already have too much IO in flight? - */ - if (cfqq->dispatched >= max_dispatch) { - bool promote_sync = false; - /* - * idle queue must always only have a single IO in flight - */ - if (cfq_class_idle(cfqq)) - return false; - - /* - * If there is only one sync queue - * we can ignore async queue here and give the sync - * queue no dispatch limit. The reason is a sync queue can - * preempt async queue, limiting the sync queue doesn't make - * sense. This is useful for aiostress test. - */ - if (cfq_cfqq_sync(cfqq) && cfqd->busy_sync_queues == 1) - promote_sync = true; - - /* - * We have other queues, don't allow more IO from this one - */ - if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq) && - !promote_sync) - return false; - - /* - * Sole queue user, no limit - */ - if (cfqd->busy_queues == 1 || promote_sync) - max_dispatch = -1; - else - /* - * Normally we start throttling cfqq when cfq_quantum/2 - * requests have been dispatched. But we can drive - * deeper queue depths at the beginning of slice - * subjected to upper limit of cfq_quantum. - * */ - max_dispatch = cfqd->cfq_quantum; - } - - /* - * 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 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 - */ - rq = cfq_check_fifo(cfqq); - if (!rq) - rq = cfqq->next_rq; - - /* - * insert request into driver dispatch list - */ - cfq_dispatch_insert(cfqd->queue, rq); - - if (!cfqd->active_cic) { - struct cfq_io_cq *cic = RQ_CIC(rq); - - atomic_long_inc(&cic->icq.ioc->refcount); - cfqd->active_cic = cic; - } - - return true; -} - -/* - * Find the cfqq that we need to service and move a request from that to the - * dispatch list - */ -static int cfq_dispatch_requests(struct request_queue *q, int force) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq; - - if (!cfqd->busy_queues) - return 0; - - if (unlikely(force)) - return cfq_forced_dispatch(cfqd); - - cfqq = cfq_select_queue(cfqd); - if (!cfqq) - return 0; - - /* - * Dispatch a request from this cfqq, if it is allowed - */ - if (!cfq_dispatch_request(cfqd, cfqq)) - return 0; - - cfqq->slice_dispatch++; - cfq_clear_cfqq_must_dispatch(cfqq); - - /* - * expire an async queue immediately if it has used up its slice. idle - * queue always expire after 1 dispatch round. - */ - if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && - cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) || - cfq_class_idle(cfqq))) { - cfqq->slice_end = jiffies + 1; - cfq_slice_expired(cfqd, 0); - } - - cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); - return 1; -} - -/* - * 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; - - BUG_ON(cfqq->ref <= 0); - - cfqq->ref--; - if (cfqq->ref) - return; - - 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; - - 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); -} - -static void cfq_put_cooperator(struct cfq_queue *cfqq) -{ - struct cfq_queue *__cfqq, *next; - - /* - * 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; - } -} - -static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - if (unlikely(cfqq == cfqd->active_queue)) { - __cfq_slice_expired(cfqd, cfqq, 0); - cfq_schedule_dispatch(cfqd); - } - - cfq_put_cooperator(cfqq); - - cfq_put_queue(cfqq); -} - -static void cfq_init_icq(struct io_cq *icq) -{ - struct cfq_io_cq *cic = icq_to_cic(icq); - - cic->ttime.last_end_request = jiffies; -} - -static void cfq_exit_icq(struct io_cq *icq) -{ - struct cfq_io_cq *cic = icq_to_cic(icq); - struct cfq_data *cfqd = cic_to_cfqd(cic); - - if (cic->cfqq[BLK_RW_ASYNC]) { - cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); - cic->cfqq[BLK_RW_ASYNC] = NULL; - } - - if (cic->cfqq[BLK_RW_SYNC]) { - cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]); - cic->cfqq[BLK_RW_SYNC] = NULL; - } -} - -static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) -{ - struct task_struct *tsk = current; - int ioprio_class; - - if (!cfq_cfqq_prio_changed(cfqq)) - return; - - ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); - switch (ioprio_class) { - default: - printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); - case IOPRIO_CLASS_NONE: - /* - * no prio set, inherit CPU scheduling settings - */ - cfqq->ioprio = task_nice_ioprio(tsk); - cfqq->ioprio_class = task_nice_ioclass(tsk); - break; - case IOPRIO_CLASS_RT: - cfqq->ioprio = task_ioprio(ioc); - cfqq->ioprio_class = IOPRIO_CLASS_RT; - break; - case IOPRIO_CLASS_BE: - cfqq->ioprio = task_ioprio(ioc); - cfqq->ioprio_class = IOPRIO_CLASS_BE; - break; - case IOPRIO_CLASS_IDLE: - cfqq->ioprio_class = IOPRIO_CLASS_IDLE; - cfqq->ioprio = 7; - cfq_clear_cfqq_idle_window(cfqq); - break; - } - - /* - * keep track of original prio settings in case we have to temporarily - * elevate the priority of this queue - */ - cfqq->org_ioprio = cfqq->ioprio; - cfq_clear_cfqq_prio_changed(cfqq); -} - -static void changed_ioprio(struct cfq_io_cq *cic) -{ - struct cfq_data *cfqd = cic_to_cfqd(cic); - struct cfq_queue *cfqq; - - if (unlikely(!cfqd)) - return; - - cfqq = cic->cfqq[BLK_RW_ASYNC]; - if (cfqq) { - struct cfq_queue *new_cfqq; - new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->icq.ioc, - GFP_ATOMIC); - if (new_cfqq) { - cic->cfqq[BLK_RW_ASYNC] = new_cfqq; - cfq_put_queue(cfqq); - } - } - - cfqq = cic->cfqq[BLK_RW_SYNC]; - if (cfqq) - cfq_mark_cfqq_prio_changed(cfqq); -} - -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); - - 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 cfq_io_cq *cic) -{ - struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1); - struct cfq_data *cfqd = cic_to_cfqd(cic); - struct request_queue *q; - - if (unlikely(!cfqd)) - return; - - q = cfqd->queue; - - 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); - } -} -#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) -{ - struct cfq_queue *cfqq, *new_cfqq = NULL; - struct cfq_io_cq *cic; - struct cfq_group *cfqg; - -retry: - cfqg = cfq_get_cfqg(cfqd); - cic = cfq_cic_lookup(cfqd, ioc); - /* cic always exists here */ - cfqq = cic_to_cfqq(cic, is_sync); - - /* - * 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) { - spin_unlock_irq(cfqd->queue->queue_lock); - new_cfqq = kmem_cache_alloc_node(cfq_pool, - gfp_mask | __GFP_ZERO, - cfqd->queue->node); - spin_lock_irq(cfqd->queue->queue_lock); - if (new_cfqq) - goto retry; - } else { - cfqq = kmem_cache_alloc_node(cfq_pool, - gfp_mask | __GFP_ZERO, - cfqd->queue->node); - } - - 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); - - return cfqq; -} - -static struct cfq_queue ** -cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) -{ - switch (ioprio_class) { - case IOPRIO_CLASS_RT: - return &cfqd->async_cfqq[0][ioprio]; - case IOPRIO_CLASS_BE: - return &cfqd->async_cfqq[1][ioprio]; - case IOPRIO_CLASS_IDLE: - return &cfqd->async_idle_cfqq; - default: - BUG(); - } -} - -static struct cfq_queue * -cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc, - gfp_t gfp_mask) -{ - const int ioprio = task_ioprio(ioc); - const int ioprio_class = task_ioprio_class(ioc); - struct cfq_queue **async_cfqq = NULL; - struct cfq_queue *cfqq = NULL; - - if (!is_sync) { - async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); - cfqq = *async_cfqq; - } - - if (!cfqq) - cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); - - /* - * pin the queue now that it's allocated, scheduler exit will prune it - */ - if (!is_sync && !(*async_cfqq)) { - cfqq->ref++; - *async_cfqq = cfqq; - } - - cfqq->ref++; - return cfqq; -} - -static void -__cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle) -{ - unsigned long elapsed = jiffies - ttime->last_end_request; - elapsed = min(elapsed, 2UL * slice_idle); - - ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8; - ttime->ttime_total = (7*ttime->ttime_total + 256*elapsed) / 8; - ttime->ttime_mean = (ttime->ttime_total + 128) / ttime->ttime_samples; -} - -static void -cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_io_cq *cic) -{ - if (cfq_cfqq_sync(cfqq)) { - __cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle); - __cfq_update_io_thinktime(&cfqq->service_tree->ttime, - cfqd->cfq_slice_idle); - } -#ifdef CONFIG_CFQ_GROUP_IOSCHED - __cfq_update_io_thinktime(&cfqq->cfqg->ttime, cfqd->cfq_group_idle); -#endif -} - -static void -cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct request *rq) -{ - sector_t sdist = 0; - sector_t n_sec = blk_rq_sectors(rq); - if (cfqq->last_request_pos) { - if (cfqq->last_request_pos < blk_rq_pos(rq)) - sdist = blk_rq_pos(rq) - cfqq->last_request_pos; - else - sdist = cfqq->last_request_pos - blk_rq_pos(rq); - } - - cfqq->seek_history <<= 1; - if (blk_queue_nonrot(cfqd->queue)) - cfqq->seek_history |= (n_sec < CFQQ_SECT_THR_NONROT); - else - cfqq->seek_history |= (sdist > CFQQ_SEEK_THR); -} - -/* - * Disable idle window if the process thinks too long or seeks so much that - * it doesn't matter - */ -static void -cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_io_cq *cic) -{ - int old_idle, enable_idle; - - /* - * Don't idle for async or idle io prio class - */ - if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) - return; - - enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); - - if (cfqq->queued[0] + cfqq->queued[1] >= 4) - cfq_mark_cfqq_deep(cfqq); - - if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE)) - enable_idle = 0; - else if (!atomic_read(&cic->icq.ioc->nr_tasks) || - !cfqd->cfq_slice_idle || - (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) - enable_idle = 0; - else if (sample_valid(cic->ttime.ttime_samples)) { - if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle) - enable_idle = 0; - else - enable_idle = 1; - } - - if (old_idle != enable_idle) { - cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); - if (enable_idle) - cfq_mark_cfqq_idle_window(cfqq); - else - cfq_clear_cfqq_idle_window(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 bool -cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, - struct request *rq) -{ - struct cfq_queue *cfqq; - - cfqq = cfqd->active_queue; - if (!cfqq) - return false; - - if (cfq_class_idle(new_cfqq)) - return false; - - if (cfq_class_idle(cfqq)) - 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 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->cmd_flags & REQ_PRIO) && !cfqq->prio_pending) - 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 true; - - /* An idle queue should not be idle now for some reason */ - if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) - return true; - - if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) - 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, cfqq, rq)) - return true; - - return false; -} - -/* - * cfqq preempts the active queue. if we allowed preempt with no slice left, - * let it have half of its nominal slice. - */ -static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - enum wl_type_t old_type = cfqq_type(cfqd->active_queue); - - cfq_log_cfqq(cfqd, cfqq, "preempt"); - cfq_slice_expired(cfqd, 1); - - /* - * workload type is changed, don't save slice, otherwise preempt - * doesn't happen - */ - if (old_type != cfqq_type(cfqq)) - cfqq->cfqg->saved_workload_slice = 0; - - /* - * Put the new queue at the front of the of the current list, - * so we know that it will be selected next. - */ - BUG_ON(!cfq_cfqq_on_rr(cfqq)); - - cfq_service_tree_add(cfqd, cfqq, 1); - - cfqq->slice_end = 0; - cfq_mark_cfqq_slice_new(cfqq); -} - -/* - * Called when a new fs request (rq) is added (to cfqq). Check if there's - * something we should do about it - */ -static void -cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct request *rq) -{ - struct cfq_io_cq *cic = RQ_CIC(rq); - - cfqd->rq_queued++; - if (rq->cmd_flags & REQ_PRIO) - cfqq->prio_pending++; - - cfq_update_io_thinktime(cfqd, cfqq, cic); - cfq_update_io_seektime(cfqd, cfqq, rq); - cfq_update_idle_window(cfqd, cfqq, cic); - - cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); - - if (cfqq == cfqd->active_queue) { - /* - * Remember that we saw a request from this process, but - * don't start queuing just yet. Otherwise we risk seeing lots - * of tiny requests, because we disrupt the normal plugging - * and merging. If the request is already larger than a single - * page, let it rip immediately. For that case we assume that - * merging is already done. Ditto for a busy system that - * has other work pending, don't risk delaying until the - * idle timer unplug to continue working. - */ - if (cfq_cfqq_wait_request(cfqq)) { - if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE || - cfqd->busy_queues > 1) { - cfq_del_timer(cfqd, cfqq); - cfq_clear_cfqq_wait_request(cfqq); - __blk_run_queue(cfqd->queue); - } else { - cfq_blkiocg_update_idle_time_stats( - &cfqq->cfqg->blkg); - cfq_mark_cfqq_must_dispatch(cfqq); - } - } - } else if (cfq_should_preempt(cfqd, cfqq, rq)) { - /* - * not the active queue - expire current slice if it is - * idle and has expired it's mean thinktime or this new queue - * has some old slice time left and is of higher priority or - * this new queue is RT and the current one is BE - */ - cfq_preempt_queue(cfqd, cfqq); - __blk_run_queue(cfqd->queue); - } -} - -static void cfq_insert_request(struct request_queue *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq = RQ_CFQQ(rq); - - cfq_log_cfqq(cfqd, cfqq, "insert_request"); - cfq_init_prio_data(cfqq, RQ_CIC(rq)->icq.ioc); - - 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_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg, - &cfqd->serving_group->blkg, rq_data_dir(rq), - rq_is_sync(rq)); - cfq_rq_enqueued(cfqd, cfqq, rq); -} - -/* - * Update hw_tag based on peak queue depth over 50 samples under - * sufficient load. - */ -static void cfq_update_hw_tag(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq = cfqd->active_queue; - - if (cfqd->rq_in_driver > cfqd->hw_tag_est_depth) - cfqd->hw_tag_est_depth = cfqd->rq_in_driver; - - if (cfqd->hw_tag == 1) - return; - - if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && - cfqd->rq_in_driver <= 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 && cfqd->rq_in_driver < CFQ_HW_QUEUE_MIN) - return; - - if (cfqd->hw_tag_samples++ < 50) - return; - - 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_cq *cic = cfqd->active_cic; - - /* If the queue already has requests, don't wait */ - if (!RB_EMPTY_ROOT(&cfqq->sort_list)) - return false; - - /* If there are other queues in the group, don't wait */ - if (cfqq->cfqg->nr_cfqq > 1) - return false; - - /* the only queue in the group, but think time is big */ - if (cfq_io_thinktime_big(cfqd, &cfqq->cfqg->ttime, true)) - 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.ttime_samples) - && (cfqq->slice_end - jiffies < cic->ttime.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); - struct cfq_data *cfqd = cfqq->cfqd; - const int sync = rq_is_sync(rq); - unsigned long now; - - now = jiffies; - cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", - !!(rq->cmd_flags & REQ_NOIDLE)); - - cfq_update_hw_tag(cfqd); - - WARN_ON(!cfqd->rq_in_driver); - WARN_ON(!cfqq->dispatched); - cfqd->rq_in_driver--; - cfqq->dispatched--; - (RQ_CFQG(rq))->dispatched--; - cfq_blkiocg_update_completion_stats(&cfqq->cfqg->blkg, - rq_start_time_ns(rq), rq_io_start_time_ns(rq), - rq_data_dir(rq), rq_is_sync(rq)); - - cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; - - if (sync) { - struct cfq_rb_root *service_tree; - - RQ_CIC(rq)->ttime.last_end_request = now; - - if (cfq_cfqq_on_rr(cfqq)) - service_tree = cfqq->service_tree; - else - service_tree = service_tree_for(cfqq->cfqg, - cfqq_prio(cfqq), cfqq_type(cfqq)); - service_tree->ttime.last_end_request = now; - if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now)) - cfqd->last_delayed_sync = now; - } - -#ifdef CONFIG_CFQ_GROUP_IOSCHED - cfqq->cfqg->ttime.last_end_request = now; -#endif - - /* - * If this is the active queue, check if it needs to be expired, - * or if we want to idle in case it has no pending requests. - */ - if (cfqd->active_queue == cfqq) { - const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list); - - if (cfq_cfqq_slice_new(cfqq)) { - cfq_set_prio_slice(cfqd, cfqq); - cfq_clear_cfqq_slice_new(cfqq); - } - - /* - * Should we wait for next request to come in before we expire - * the queue. - */ - if (cfq_should_wait_busy(cfqd, cfqq)) { - unsigned long extend_sl = cfqd->cfq_slice_idle; - if (!cfqd->cfq_slice_idle) - extend_sl = cfqd->cfq_group_idle; - cfqq->slice_end = jiffies + extend_sl; - cfq_mark_cfqq_wait_busy(cfqq); - cfq_log_cfqq(cfqd, cfqq, "will busy wait"); - } - - /* - * 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 (sync && cfqq_empty && - !cfq_close_cooperator(cfqd, cfqq)) { - cfq_arm_slice_timer(cfqd); - } - } - - if (!cfqd->rq_in_driver) - cfq_schedule_dispatch(cfqd); -} - -static inline int __cfq_may_queue(struct cfq_queue *cfqq) -{ - if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) { - cfq_mark_cfqq_must_alloc_slice(cfqq); - return ELV_MQUEUE_MUST; - } - - return ELV_MQUEUE_MAY; -} - -static int cfq_may_queue(struct request_queue *q, int rw) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct task_struct *tsk = current; - struct cfq_io_cq *cic; - struct cfq_queue *cfqq; - - /* - * don't force setup of a queue from here, as a call to may_queue - * does not necessarily imply that a request actually will be queued. - * so just lookup a possibly existing queue, or return 'may queue' - * if that fails - */ - cic = cfq_cic_lookup(cfqd, tsk->io_context); - if (!cic) - return ELV_MQUEUE_MAY; - - cfqq = cic_to_cfqq(cic, rw_is_sync(rw)); - if (cfqq) { - cfq_init_prio_data(cfqq, cic->icq.ioc); - - return __cfq_may_queue(cfqq); - } - - return ELV_MQUEUE_MAY; -} - -/* - * queue lock held here - */ -static void cfq_put_request(struct request *rq) -{ - struct cfq_queue *cfqq = RQ_CFQQ(rq); - - if (cfqq) { - const int rw = rq_data_dir(rq); - - BUG_ON(!cfqq->allocated[rw]); - cfqq->allocated[rw]--; - - /* Put down rq reference on cfqg */ - cfq_put_cfqg(RQ_CFQG(rq)); - rq->elv.priv[0] = NULL; - rq->elv.priv[1] = NULL; - - cfq_put_queue(cfqq); - } -} - -static struct cfq_queue * -cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_cq *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); -} - -/* - * 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_cq *cic, struct cfq_queue *cfqq) -{ - if (cfqq_process_refs(cfqq) == 1) { - cfqq->pid = current->pid; - cfq_clear_cfqq_coop(cfqq); - cfq_clear_cfqq_split_coop(cfqq); - return cfqq; - } - - cic_set_cfqq(cic, NULL, 1); - - cfq_put_cooperator(cfqq); - - cfq_put_queue(cfqq); - return NULL; -} -/* - * Allocate cfq data structures associated with this request. - */ -static int -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_cq *cic = icq_to_cic(rq->elv.icq); - const int rw = rq_data_dir(rq); - const bool is_sync = rq_is_sync(rq); - struct cfq_queue *cfqq; - unsigned int changed; - - might_sleep_if(gfp_mask & __GFP_WAIT); - - spin_lock_irq(q->queue_lock); - - /* handle changed notifications */ - changed = icq_get_changed(&cic->icq); - if (unlikely(changed & ICQ_IOPRIO_CHANGED)) - changed_ioprio(cic); -#ifdef CONFIG_CFQ_GROUP_IOSCHED - if (unlikely(changed & ICQ_CGROUP_CHANGED)) - changed_cgroup(cic); -#endif - -new_queue: - cfqq = cic_to_cfqq(cic, is_sync); - if (!cfqq || cfqq == &cfqd->oom_cfqq) { - cfqq = cfq_get_queue(cfqd, is_sync, cic->icq.ioc, gfp_mask); - cic_set_cfqq(cic, cfqq, is_sync); - } else { - /* - * If the queue was seeky for too long, break it apart. - */ - 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) - 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]++; - - cfqq->ref++; - rq->elv.priv[0] = cfqq; - rq->elv.priv[1] = cfq_ref_get_cfqg(cfqq->cfqg); - spin_unlock_irq(q->queue_lock); - return 0; -} - -static void cfq_kick_queue(struct work_struct *work) -{ - struct cfq_data *cfqd = - container_of(work, struct cfq_data, unplug_work); - struct request_queue *q = cfqd->queue; - - spin_lock_irq(q->queue_lock); - __blk_run_queue(cfqd->queue); - spin_unlock_irq(q->queue_lock); -} - -/* - * Timer running if the active_queue is currently idling inside its time slice - */ -static void cfq_idle_slice_timer(unsigned long data) -{ - struct cfq_data *cfqd = (struct cfq_data *) data; - struct cfq_queue *cfqq; - unsigned long flags; - int timed_out = 1; - - cfq_log(cfqd, "idle timer fired"); - - spin_lock_irqsave(cfqd->queue->queue_lock, flags); - - cfqq = cfqd->active_queue; - if (cfqq) { - timed_out = 0; - - /* - * We saw a request before the queue expired, let it through - */ - if (cfq_cfqq_must_dispatch(cfqq)) - goto out_kick; - - /* - * expired - */ - if (cfq_slice_used(cfqq)) - goto expire; - - /* - * only expire and reinvoke request handler, if there are - * other queues with pending requests - */ - if (!cfqd->busy_queues) - goto out_cont; - - /* - * not expired and it has a request pending, let it dispatch - */ - 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); -out_kick: - cfq_schedule_dispatch(cfqd); -out_cont: - spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); -} - -static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) -{ - del_timer_sync(&cfqd->idle_slice_timer); - cancel_work_sync(&cfqd->unplug_work); -} - -static void cfq_put_async_queues(struct cfq_data *cfqd) -{ - int i; - - for (i = 0; i < IOPRIO_BE_NR; i++) { - if (cfqd->async_cfqq[0][i]) - cfq_put_queue(cfqd->async_cfqq[0][i]); - if (cfqd->async_cfqq[1][i]) - cfq_put_queue(cfqd->async_cfqq[1][i]); - } - - if (cfqd->async_idle_cfqq) - cfq_put_queue(cfqd->async_idle_cfqq); -} - -static void cfq_exit_queue(struct elevator_queue *e) -{ - struct cfq_data *cfqd = e->elevator_data; - struct request_queue *q = cfqd->queue; - bool wait = false; - - cfq_shutdown_timer_wq(cfqd); - - spin_lock_irq(q->queue_lock); - - if (cfqd->active_queue) - __cfq_slice_expired(cfqd, cfqd->active_queue, 0); - - cfq_put_async_queues(cfqd); - cfq_release_cfq_groups(cfqd); - - /* - * If there are groups which we could not unlink from blkcg list, - * wait for a rcu period for them to be freed. - */ - if (cfqd->nr_blkcg_linked_grps) - wait = true; - - spin_unlock_irq(q->queue_lock); - - cfq_shutdown_timer_wq(cfqd); - - /* - * Wait for cfqg->blkg->key accessors to exit their grace periods. - * Do this wait only if there are other unlinked groups out - * there. This can happen if cgroup deletion path claimed the - * responsibility of cleaning up a group before queue cleanup code - * get to the group. - * - * Do not call synchronize_rcu() unconditionally as there are drivers - * which create/delete request queue hundreds of times during scan/boot - * and synchronize_rcu() can take significant time and slow down boot. - */ - if (wait) - synchronize_rcu(); - -#ifdef CONFIG_CFQ_GROUP_IOSCHED - /* Free up per cpu stats for root group */ - free_percpu(cfqd->root_group.blkg.stats_cpu); -#endif - kfree(cfqd); -} - -static void *cfq_init_queue(struct request_queue *q) -{ - struct cfq_data *cfqd; - 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; - - /* 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 - /* - * Set root group reference to 2. One reference will be dropped when - * all groups on cfqd->cfqg_list are being deleted during queue exit. - * Other reference will remain there as we don't want to delete this - * group as it is statically allocated and gets destroyed when - * throtl_data goes away. - */ - cfqg->ref = 2; - - if (blkio_alloc_blkg_stats(&cfqg->blkg)) { - kfree(cfqg); - kfree(cfqd); - return NULL; - } - - rcu_read_lock(); - - cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, - (void *)cfqd, 0); - rcu_read_unlock(); - cfqd->nr_blkcg_linked_grps++; - - /* Add group on cfqd->cfqg_list */ - hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list); -#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 - * to add magic to the rb code - */ - 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); - cfqd->oom_cfqq.ref++; - cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); - - cfqd->queue = q; - - init_timer(&cfqd->idle_slice_timer); - cfqd->idle_slice_timer.function = cfq_idle_slice_timer; - cfqd->idle_slice_timer.data = (unsigned long) cfqd; - - INIT_WORK(&cfqd->unplug_work, cfq_kick_queue); - - cfqd->cfq_quantum = cfq_quantum; - cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; - cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; - cfqd->cfq_back_max = cfq_back_max; - cfqd->cfq_back_penalty = cfq_back_penalty; - cfqd->cfq_slice[0] = cfq_slice_async; - cfqd->cfq_slice[1] = cfq_slice_sync; - cfqd->cfq_target_latency = cfq_target_latency; - cfqd->cfq_slice_async_rq = cfq_slice_async_rq; - cfqd->cfq_slice_idle = cfq_slice_idle; - cfqd->cfq_group_idle = cfq_group_idle; - cfqd->cfq_latency = 1; - 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; - return cfqd; -} - -/* - * sysfs parts below --> - */ -static ssize_t -cfq_var_show(unsigned int var, char *page) -{ - return sprintf(page, "%d\n", var); -} - -static ssize_t -cfq_var_store(unsigned int *var, const char *page, size_t count) -{ - char *p = (char *) page; - - *var = simple_strtoul(p, &p, 10); - return count; -} - -#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ -static ssize_t __FUNC(struct elevator_queue *e, char *page) \ -{ \ - struct cfq_data *cfqd = e->elevator_data; \ - unsigned int __data = __VAR; \ - if (__CONV) \ - __data = jiffies_to_msecs(__data); \ - return cfq_var_show(__data, (page)); \ -} -SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); -SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); -SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); -SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); -SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); -SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); -SHOW_FUNCTION(cfq_group_idle_show, cfqd->cfq_group_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_target_latency_show, cfqd->cfq_target_latency, 1); -#undef SHOW_FUNCTION - -#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ -static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ -{ \ - struct cfq_data *cfqd = e->elevator_data; \ - unsigned int __data; \ - int ret = cfq_var_store(&__data, (page), count); \ - if (__data < (MIN)) \ - __data = (MIN); \ - else if (__data > (MAX)) \ - __data = (MAX); \ - if (__CONV) \ - *(__PTR) = msecs_to_jiffies(__data); \ - else \ - *(__PTR) = __data; \ - return ret; \ -} -STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, - UINT_MAX, 1); -STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, - UINT_MAX, 1); -STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); -STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, - UINT_MAX, 0); -STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); -STORE_FUNCTION(cfq_group_idle_store, &cfqd->cfq_group_idle, 0, UINT_MAX, 1); -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_target_latency_store, &cfqd->cfq_target_latency, 1, UINT_MAX, 1); -#undef STORE_FUNCTION - -#define CFQ_ATTR(name) \ - __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) - -static struct elv_fs_entry cfq_attrs[] = { - CFQ_ATTR(quantum), - CFQ_ATTR(fifo_expire_sync), - CFQ_ATTR(fifo_expire_async), - CFQ_ATTR(back_seek_max), - CFQ_ATTR(back_seek_penalty), - CFQ_ATTR(slice_sync), - CFQ_ATTR(slice_async), - CFQ_ATTR(slice_async_rq), - CFQ_ATTR(slice_idle), - CFQ_ATTR(group_idle), - CFQ_ATTR(low_latency), - CFQ_ATTR(target_latency), - __ATTR_NULL -}; - -static struct elevator_type iosched_cfq = { - .ops = { - .elevator_merge_fn = cfq_merge, - .elevator_merged_fn = cfq_merged_request, - .elevator_merge_req_fn = cfq_merged_requests, - .elevator_allow_merge_fn = cfq_allow_merge, - .elevator_bio_merged_fn = cfq_bio_merged, - .elevator_dispatch_fn = cfq_dispatch_requests, - .elevator_add_req_fn = cfq_insert_request, - .elevator_activate_req_fn = cfq_activate_request, - .elevator_deactivate_req_fn = cfq_deactivate_request, - .elevator_completed_req_fn = cfq_completed_request, - .elevator_former_req_fn = elv_rb_former_request, - .elevator_latter_req_fn = elv_rb_latter_request, - .elevator_init_icq_fn = cfq_init_icq, - .elevator_exit_icq_fn = cfq_exit_icq, - .elevator_set_req_fn = cfq_set_request, - .elevator_put_req_fn = cfq_put_request, - .elevator_may_queue_fn = cfq_may_queue, - .elevator_init_fn = cfq_init_queue, - .elevator_exit_fn = cfq_exit_queue, - }, - .icq_size = sizeof(struct cfq_io_cq), - .icq_align = __alignof__(struct cfq_io_cq), - .elevator_attrs = cfq_attrs, - .elevator_name = "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, - }, - .plid = BLKIO_POLICY_PROP, -}; -#else -static struct blkio_policy_type blkio_policy_cfq; -#endif - -static int __init cfq_init(void) -{ - int ret; - - /* - * could be 0 on HZ < 1000 setups - */ - if (!cfq_slice_async) - cfq_slice_async = 1; - if (!cfq_slice_idle) - cfq_slice_idle = 1; - -#ifdef CONFIG_CFQ_GROUP_IOSCHED - if (!cfq_group_idle) - cfq_group_idle = 1; -#else - cfq_group_idle = 0; -#endif - cfq_pool = KMEM_CACHE(cfq_queue, 0); - if (!cfq_pool) - return -ENOMEM; - - ret = elv_register(&iosched_cfq); - if (ret) { - kmem_cache_destroy(cfq_pool); - return ret; - } - - blkio_policy_register(&blkio_policy_cfq); - - return 0; -} - -static void __exit cfq_exit(void) -{ - blkio_policy_unregister(&blkio_policy_cfq); - elv_unregister(&iosched_cfq); - kmem_cache_destroy(cfq_pool); -} - -module_init(cfq_init); -module_exit(cfq_exit); - -MODULE_AUTHOR("Jens Axboe"); -MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |