176 lines
4.0 KiB
C
176 lines
4.0 KiB
C
#ifndef WB_THROTTLE_H
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#define WB_THROTTLE_H
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#include <linux/kernel.h>
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#include <linux/atomic.h>
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#include <linux/wait.h>
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#include <linux/timer.h>
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#include <linux/ktime.h>
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#include "blk-stat.h"
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enum wbt_flags {
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WBT_TRACKED = 1, /* write, tracked for throttling */
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WBT_READ = 2, /* read */
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WBT_KSWAPD = 4, /* write, from kswapd */
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WBT_NR_BITS = 3, /* number of bits */
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};
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enum {
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WBT_NUM_RWQ = 2,
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};
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/*
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* Enable states. Either off, or on by default (done at init time),
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* or on through manual setup in sysfs.
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*/
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enum {
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WBT_STATE_ON_DEFAULT = 1,
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WBT_STATE_ON_MANUAL = 2,
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};
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static inline void wbt_clear_state(struct blk_issue_stat *stat)
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{
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stat->stat &= ~BLK_STAT_RES_MASK;
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}
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static inline enum wbt_flags wbt_stat_to_mask(struct blk_issue_stat *stat)
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{
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return (stat->stat & BLK_STAT_RES_MASK) >> BLK_STAT_RES_SHIFT;
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}
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static inline void wbt_track(struct blk_issue_stat *stat, enum wbt_flags wb_acct)
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{
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stat->stat |= ((u64) wb_acct) << BLK_STAT_RES_SHIFT;
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}
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static inline bool wbt_is_tracked(struct blk_issue_stat *stat)
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{
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return (stat->stat >> BLK_STAT_RES_SHIFT) & WBT_TRACKED;
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}
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static inline bool wbt_is_read(struct blk_issue_stat *stat)
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{
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return (stat->stat >> BLK_STAT_RES_SHIFT) & WBT_READ;
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}
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struct rq_wait {
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wait_queue_head_t wait;
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atomic_t inflight;
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};
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struct rq_wb {
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/*
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* Settings that govern how we throttle
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*/
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unsigned int wb_background; /* background writeback */
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unsigned int wb_normal; /* normal writeback */
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unsigned int wb_max; /* max throughput writeback */
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int scale_step;
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bool scaled_max;
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short enable_state; /* WBT_STATE_* */
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/*
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* Number of consecutive periods where we don't have enough
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* information to make a firm scale up/down decision.
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*/
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unsigned int unknown_cnt;
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u64 win_nsec; /* default window size */
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u64 cur_win_nsec; /* current window size */
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struct blk_stat_callback *cb;
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s64 sync_issue;
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void *sync_cookie;
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unsigned int wc;
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unsigned int queue_depth;
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unsigned long last_issue; /* last non-throttled issue */
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unsigned long last_comp; /* last non-throttled comp */
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unsigned long min_lat_nsec;
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struct request_queue *queue;
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struct rq_wait rq_wait[WBT_NUM_RWQ];
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};
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static inline unsigned int wbt_inflight(struct rq_wb *rwb)
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{
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unsigned int i, ret = 0;
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for (i = 0; i < WBT_NUM_RWQ; i++)
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ret += atomic_read(&rwb->rq_wait[i].inflight);
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return ret;
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}
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#ifdef CONFIG_BLK_WBT
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void __wbt_done(struct rq_wb *, enum wbt_flags);
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void wbt_done(struct rq_wb *, struct blk_issue_stat *);
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enum wbt_flags wbt_wait(struct rq_wb *, struct bio *, spinlock_t *);
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int wbt_init(struct request_queue *);
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void wbt_exit(struct request_queue *);
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void wbt_update_limits(struct rq_wb *);
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void wbt_requeue(struct rq_wb *, struct blk_issue_stat *);
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void wbt_issue(struct rq_wb *, struct blk_issue_stat *);
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void wbt_disable_default(struct request_queue *);
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void wbt_enable_default(struct request_queue *);
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void wbt_set_queue_depth(struct rq_wb *, unsigned int);
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void wbt_set_write_cache(struct rq_wb *, bool);
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u64 wbt_default_latency_nsec(struct request_queue *);
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#else
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static inline void __wbt_done(struct rq_wb *rwb, enum wbt_flags flags)
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{
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}
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static inline void wbt_done(struct rq_wb *rwb, struct blk_issue_stat *stat)
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{
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}
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static inline enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio,
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spinlock_t *lock)
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{
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return 0;
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}
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static inline int wbt_init(struct request_queue *q)
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{
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return -EINVAL;
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}
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static inline void wbt_exit(struct request_queue *q)
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{
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}
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static inline void wbt_update_limits(struct rq_wb *rwb)
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{
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}
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static inline void wbt_requeue(struct rq_wb *rwb, struct blk_issue_stat *stat)
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{
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}
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static inline void wbt_issue(struct rq_wb *rwb, struct blk_issue_stat *stat)
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{
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}
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static inline void wbt_disable_default(struct request_queue *q)
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{
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}
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static inline void wbt_enable_default(struct request_queue *q)
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{
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}
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static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
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{
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}
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static inline void wbt_set_write_cache(struct rq_wb *rwb, bool wc)
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{
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}
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static inline u64 wbt_default_latency_nsec(struct request_queue *q)
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{
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return 0;
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}
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#endif /* CONFIG_BLK_WBT */
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#endif
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