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https://github.com/torvalds/linux
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8330cdb0fe
When CFQ is used as an elevator, it disables writeback throttling because they don't play well together. Later when a different elevator is chosen for the device, writeback throttling doesn't get enabled again as it should. Make sure CFQ enables writeback throttling (if it should be enabled by default) when we switch from it to another IO scheduler. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
175 lines
4 KiB
C
175 lines
4 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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