diff options
Diffstat (limited to 'block/blk-throttle.c')
| -rw-r--r-- | block/blk-throttle.c | 161 |
1 files changed, 3 insertions, 158 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 7c4e7993ba97..8cefd14deed5 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -13,6 +13,7 @@ #include <linux/blk-cgroup.h> #include "blk.h" #include "blk-cgroup-rwstat.h" +#include "blk-throttle.h" /* Max dispatch from a group in 1 round */ #define THROTL_GRP_QUANTUM 8 @@ -37,60 +38,9 @@ */ #define LATENCY_FILTERED_HD (1000L) /* 1ms */ -static struct blkcg_policy blkcg_policy_throtl; - /* A workqueue to queue throttle related work */ static struct workqueue_struct *kthrotld_workqueue; -/* - * To implement hierarchical throttling, throtl_grps form a tree and bios - * are dispatched upwards level by level until they reach the top and get - * issued. When dispatching bios from the children and local group at each - * level, if the bios are dispatched into a single bio_list, there's a risk - * of a local or child group which can queue many bios at once filling up - * the list starving others. - * - * To avoid such starvation, dispatched bios are queued separately - * according to where they came from. When they are again dispatched to - * the parent, they're popped in round-robin order so that no single source - * hogs the dispatch window. - * - * throtl_qnode is used to keep the queued bios separated by their sources. - * Bios are queued to throtl_qnode which in turn is queued to - * throtl_service_queue and then dispatched in round-robin order. - * - * It's also used to track the reference counts on blkg's. A qnode always - * belongs to a throtl_grp and gets queued on itself or the parent, so - * incrementing the reference of the associated throtl_grp when a qnode is - * queued and decrementing when dequeued is enough to keep the whole blkg - * tree pinned while bios are in flight. - */ -struct throtl_qnode { - struct list_head node; /* service_queue->queued[] */ - struct bio_list bios; /* queued bios */ - struct throtl_grp *tg; /* tg this qnode belongs to */ -}; - -struct throtl_service_queue { - struct throtl_service_queue *parent_sq; /* the parent service_queue */ - - /* - * Bios queued directly to this service_queue or dispatched from - * children throtl_grp's. - */ - struct list_head queued[2]; /* throtl_qnode [READ/WRITE] */ - unsigned int nr_queued[2]; /* number of queued bios */ - - /* - * RB tree of active children throtl_grp's, which are sorted by - * their ->disptime. - */ - struct rb_root_cached pending_tree; /* RB tree of active tgs */ - unsigned int nr_pending; /* # queued in the tree */ - unsigned long first_pending_disptime; /* disptime of the first tg */ - struct timer_list pending_timer; /* fires on first_pending_disptime */ -}; - enum tg_state_flags { THROTL_TG_PENDING = 1 << 0, /* on parent's pending tree */ THROTL_TG_WAS_EMPTY = 1 << 1, /* bio_lists[] became non-empty */ @@ -98,93 +48,6 @@ enum tg_state_flags { #define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node) -enum { - LIMIT_LOW, - LIMIT_MAX, - LIMIT_CNT, -}; - -struct throtl_grp { - /* must be the first member */ - struct blkg_policy_data pd; - - /* active throtl group service_queue member */ - struct rb_node rb_node; - - /* throtl_data this group belongs to */ - struct throtl_data *td; - - /* this group's service queue */ - struct throtl_service_queue service_queue; - - /* - * qnode_on_self is used when bios are directly queued to this - * throtl_grp so that local bios compete fairly with bios - * dispatched from children. qnode_on_parent is used when bios are - * dispatched from this throtl_grp into its parent and will compete - * with the sibling qnode_on_parents and the parent's - * qnode_on_self. - */ - struct throtl_qnode qnode_on_self[2]; - struct throtl_qnode qnode_on_parent[2]; - - /* - * Dispatch time in jiffies. This is the estimated time when group - * will unthrottle and is ready to dispatch more bio. It is used as - * key to sort active groups in service tree. - */ - unsigned long disptime; - - unsigned int flags; - - /* are there any throtl rules between this group and td? */ - bool has_rules[2]; - - /* internally used bytes per second rate limits */ - uint64_t bps[2][LIMIT_CNT]; - /* user configured bps limits */ - uint64_t bps_conf[2][LIMIT_CNT]; - - /* internally used IOPS limits */ - unsigned int iops[2][LIMIT_CNT]; - /* user configured IOPS limits */ - unsigned int iops_conf[2][LIMIT_CNT]; - - /* Number of bytes dispatched in current slice */ - uint64_t bytes_disp[2]; - /* Number of bio's dispatched in current slice */ - unsigned int io_disp[2]; - - unsigned long last_low_overflow_time[2]; - - uint64_t last_bytes_disp[2]; - unsigned int last_io_disp[2]; - - unsigned long last_check_time; - - unsigned long latency_target; /* us */ - unsigned long latency_target_conf; /* us */ - /* When did we start a new slice */ - unsigned long slice_start[2]; - unsigned long slice_end[2]; - - unsigned long last_finish_time; /* ns / 1024 */ - unsigned long checked_last_finish_time; /* ns / 1024 */ - unsigned long avg_idletime; /* ns / 1024 */ - unsigned long idletime_threshold; /* us */ - unsigned long idletime_threshold_conf; /* us */ - - unsigned int bio_cnt; /* total bios */ - unsigned int bad_bio_cnt; /* bios exceeding latency threshold */ - unsigned long bio_cnt_reset_time; - - atomic_t io_split_cnt[2]; - atomic_t last_io_split_cnt[2]; - - struct blkg_rwstat stat_bytes; - struct blkg_rwstat stat_ios; -}; - /* We measure latency for request size from <= 4k to >= 1M */ #define LATENCY_BUCKET_SIZE 9 @@ -231,16 +94,6 @@ struct throtl_data static void throtl_pending_timer_fn(struct timer_list *t); -static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) -{ - return pd ? container_of(pd, struct throtl_grp, pd) : NULL; -} - -static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg) -{ - return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl)); -} - static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg) { return pd_to_blkg(&tg->pd); @@ -1794,7 +1647,7 @@ static void throtl_shutdown_wq(struct request_queue *q) cancel_work_sync(&td->dispatch_work); } -static struct blkcg_policy blkcg_policy_throtl = { +struct blkcg_policy blkcg_policy_throtl = { .dfl_cftypes = throtl_files, .legacy_cftypes = throtl_legacy_files, @@ -2208,7 +2061,7 @@ void blk_throtl_charge_bio_split(struct bio *bio) } while (parent); } -bool blk_throtl_bio(struct bio *bio) +bool __blk_throtl_bio(struct bio *bio) { struct request_queue *q = bio->bi_bdev->bd_disk->queue; struct blkcg_gq *blkg = bio->bi_blkg; @@ -2221,19 +2074,12 @@ bool blk_throtl_bio(struct bio *bio) rcu_read_lock(); - /* see throtl_charge_bio() */ - if (bio_flagged(bio, BIO_THROTTLED)) - goto out; - if (!cgroup_subsys_on_dfl(io_cgrp_subsys)) { blkg_rwstat_add(&tg->stat_bytes, bio->bi_opf, bio->bi_iter.bi_size); blkg_rwstat_add(&tg->stat_ios, bio->bi_opf, 1); } - if (!tg->has_rules[rw]) - goto out; - spin_lock_irq(&q->queue_lock); throtl_update_latency_buckets(td); @@ -2317,7 +2163,6 @@ again: out_unlock: spin_unlock_irq(&q->queue_lock); -out: bio_set_flag(bio, BIO_THROTTLED); #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |