diff options
Diffstat (limited to 'block/blk-wbt.c')
-rw-r--r-- | block/blk-wbt.c | 116 |
1 files changed, 95 insertions, 21 deletions
diff --git a/block/blk-wbt.c b/block/blk-wbt.c index 68a774d7a7c9..e49a48684532 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -25,6 +25,7 @@ #include <linux/backing-dev.h> #include <linux/swap.h> +#include "blk-stat.h" #include "blk-wbt.h" #include "blk-rq-qos.h" #include "elevator.h" @@ -32,6 +33,72 @@ #define CREATE_TRACE_POINTS #include <trace/events/wbt.h> +enum wbt_flags { + WBT_TRACKED = 1, /* write, tracked for throttling */ + WBT_READ = 2, /* read */ + WBT_KSWAPD = 4, /* write, from kswapd */ + WBT_DISCARD = 8, /* discard */ + + WBT_NR_BITS = 4, /* number of bits */ +}; + +enum { + WBT_RWQ_BG = 0, + WBT_RWQ_KSWAPD, + WBT_RWQ_DISCARD, + WBT_NUM_RWQ, +}; + +/* + * If current state is WBT_STATE_ON/OFF_DEFAULT, it can be covered to any other + * state, if current state is WBT_STATE_ON/OFF_MANUAL, it can only be covered + * to WBT_STATE_OFF/ON_MANUAL. + */ +enum { + WBT_STATE_ON_DEFAULT = 1, /* on by default */ + WBT_STATE_ON_MANUAL = 2, /* on manually by sysfs */ + WBT_STATE_OFF_DEFAULT = 3, /* off by default */ + WBT_STATE_OFF_MANUAL = 4, /* off manually by sysfs */ +}; + +struct rq_wb { + /* + * Settings that govern how we throttle + */ + unsigned int wb_background; /* background writeback */ + unsigned int wb_normal; /* normal writeback */ + + short enable_state; /* WBT_STATE_* */ + + /* + * Number of consecutive periods where we don't have enough + * information to make a firm scale up/down decision. + */ + unsigned int unknown_cnt; + + u64 win_nsec; /* default window size */ + u64 cur_win_nsec; /* current window size */ + + struct blk_stat_callback *cb; + + u64 sync_issue; + void *sync_cookie; + + unsigned int wc; + + unsigned long last_issue; /* last non-throttled issue */ + unsigned long last_comp; /* last non-throttled comp */ + unsigned long min_lat_nsec; + struct rq_qos rqos; + struct rq_wait rq_wait[WBT_NUM_RWQ]; + struct rq_depth rq_depth; +}; + +static inline struct rq_wb *RQWB(struct rq_qos *rqos) +{ + return container_of(rqos, struct rq_wb, rqos); +} + static inline void wbt_clear_state(struct request *rq) { rq->wbt_flags = 0; @@ -98,7 +165,7 @@ static void wb_timestamp(struct rq_wb *rwb, unsigned long *var) */ static bool wb_recent_wait(struct rq_wb *rwb) { - struct bdi_writeback *wb = &rwb->rqos.q->disk->bdi->wb; + struct bdi_writeback *wb = &rwb->rqos.disk->bdi->wb; return time_before(jiffies, wb->dirty_sleep + HZ); } @@ -226,6 +293,16 @@ static u64 rwb_sync_issue_lat(struct rq_wb *rwb) return now - issue; } +static inline unsigned int wbt_inflight(struct rq_wb *rwb) +{ + unsigned int i, ret = 0; + + for (i = 0; i < WBT_NUM_RWQ; i++) + ret += atomic_read(&rwb->rq_wait[i].inflight); + + return ret; +} + enum { LAT_OK = 1, LAT_UNKNOWN, @@ -235,7 +312,7 @@ enum { static int latency_exceeded(struct rq_wb *rwb, struct blk_rq_stat *stat) { - struct backing_dev_info *bdi = rwb->rqos.q->disk->bdi; + struct backing_dev_info *bdi = rwb->rqos.disk->bdi; struct rq_depth *rqd = &rwb->rq_depth; u64 thislat; @@ -288,7 +365,7 @@ static int latency_exceeded(struct rq_wb *rwb, struct blk_rq_stat *stat) static void rwb_trace_step(struct rq_wb *rwb, const char *msg) { - struct backing_dev_info *bdi = rwb->rqos.q->disk->bdi; + struct backing_dev_info *bdi = rwb->rqos.disk->bdi; struct rq_depth *rqd = &rwb->rq_depth; trace_wbt_step(bdi, msg, rqd->scale_step, rwb->cur_win_nsec, @@ -358,13 +435,12 @@ static void wb_timer_fn(struct blk_stat_callback *cb) unsigned int inflight = wbt_inflight(rwb); int status; - if (!rwb->rqos.q->disk) + if (!rwb->rqos.disk) return; status = latency_exceeded(rwb, cb->stat); - trace_wbt_timer(rwb->rqos.q->disk->bdi, status, rqd->scale_step, - inflight); + trace_wbt_timer(rwb->rqos.disk->bdi, status, rqd->scale_step, inflight); /* * If we exceeded the latency target, step down. If we did not, @@ -650,8 +726,9 @@ void wbt_set_write_cache(struct request_queue *q, bool write_cache_on) /* * Enable wbt if defaults are configured that way */ -void wbt_enable_default(struct request_queue *q) +void wbt_enable_default(struct gendisk *disk) { + struct request_queue *q = disk->queue; struct rq_qos *rqos; bool disable_flag = q->elevator && test_bit(ELEVATOR_FLAG_DISABLE_WBT, &q->elevator->flags); @@ -670,7 +747,7 @@ void wbt_enable_default(struct request_queue *q) return; if (queue_is_mq(q) && !disable_flag) - wbt_init(q); + wbt_init(disk); } EXPORT_SYMBOL_GPL(wbt_enable_default); @@ -701,16 +778,15 @@ static int wbt_data_dir(const struct request *rq) static void wbt_queue_depth_changed(struct rq_qos *rqos) { - RQWB(rqos)->rq_depth.queue_depth = blk_queue_depth(rqos->q); + RQWB(rqos)->rq_depth.queue_depth = blk_queue_depth(rqos->disk->queue); wbt_update_limits(RQWB(rqos)); } static void wbt_exit(struct rq_qos *rqos) { struct rq_wb *rwb = RQWB(rqos); - struct request_queue *q = rqos->q; - blk_stat_remove_callback(q, rwb->cb); + blk_stat_remove_callback(rqos->disk->queue, rwb->cb); blk_stat_free_callback(rwb->cb); kfree(rwb); } @@ -718,9 +794,9 @@ static void wbt_exit(struct rq_qos *rqos) /* * Disable wbt, if enabled by default. */ -void wbt_disable_default(struct request_queue *q) +void wbt_disable_default(struct gendisk *disk) { - struct rq_qos *rqos = wbt_rq_qos(q); + struct rq_qos *rqos = wbt_rq_qos(disk->queue); struct rq_wb *rwb; if (!rqos) return; @@ -820,7 +896,7 @@ static const struct blk_mq_debugfs_attr wbt_debugfs_attrs[] = { }; #endif -static struct rq_qos_ops wbt_rqos_ops = { +static const struct rq_qos_ops wbt_rqos_ops = { .throttle = wbt_wait, .issue = wbt_issue, .track = wbt_track, @@ -834,8 +910,9 @@ static struct rq_qos_ops wbt_rqos_ops = { #endif }; -int wbt_init(struct request_queue *q) +int wbt_init(struct gendisk *disk) { + struct request_queue *q = disk->queue; struct rq_wb *rwb; int i; int ret; @@ -853,22 +930,19 @@ int wbt_init(struct request_queue *q) for (i = 0; i < WBT_NUM_RWQ; i++) rq_wait_init(&rwb->rq_wait[i]); - rwb->rqos.id = RQ_QOS_WBT; - rwb->rqos.ops = &wbt_rqos_ops; - rwb->rqos.q = q; rwb->last_comp = rwb->last_issue = jiffies; rwb->win_nsec = RWB_WINDOW_NSEC; rwb->enable_state = WBT_STATE_ON_DEFAULT; rwb->wc = test_bit(QUEUE_FLAG_WC, &q->queue_flags); rwb->rq_depth.default_depth = RWB_DEF_DEPTH; rwb->min_lat_nsec = wbt_default_latency_nsec(q); - - wbt_queue_depth_changed(&rwb->rqos); + rwb->rq_depth.queue_depth = blk_queue_depth(q); + wbt_update_limits(rwb); /* * Assign rwb and add the stats callback. */ - ret = rq_qos_add(q, &rwb->rqos); + ret = rq_qos_add(&rwb->rqos, disk, RQ_QOS_WBT, &wbt_rqos_ops); if (ret) goto err_free; |