1 files changed, 100 insertions, 0 deletions
diff --git a/include/linux/wbt.h b/include/linux/wbt.h
new file mode 100644
index 000000000..872da2d73
--- /dev/null
+++ b/include/linux/wbt.h
@@ -0,0 +1,100 @@
+#ifndef WB_THROTTLE_H
+#define WB_THROTTLE_H
+
+#include <linux/atomic.h>
+#include <linux/wait.h>
+#include <linux/timer.h>
+#include <linux/ktime.h>
+
+#define ISSUE_STAT_MASK		(1ULL << 63)
+#define ISSUE_STAT_TIME_MASK	~ISSUE_STAT_MASK
+
+struct wb_issue_stat {
+	u64 time;
+};
+
+static inline void wbt_issue_stat_set_time(struct wb_issue_stat *stat)
+{
+	stat->time = (stat->time & ISSUE_STAT_MASK) |
+			(ktime_to_ns(ktime_get()) & ISSUE_STAT_TIME_MASK);
+}
+
+static inline u64 wbt_issue_stat_get_time(struct wb_issue_stat *stat)
+{
+	return stat->time & ISSUE_STAT_TIME_MASK;
+}
+
+static inline void wbt_mark_tracked(struct wb_issue_stat *stat)
+{
+	stat->time |= ISSUE_STAT_MASK;
+}
+
+static inline void wbt_clear_tracked(struct wb_issue_stat *stat)
+{
+	stat->time &= ~ISSUE_STAT_MASK;
+}
+
+static inline bool wbt_tracked(struct wb_issue_stat *stat)
+{
+	return (stat->time & ISSUE_STAT_MASK) != 0;
+}
+
+struct wb_stat_ops {
+	void (*get)(void *, struct blk_rq_stat *);
+	void (*clear)(void *);
+};
+
+struct rq_wb {
+	/*
+	 * Settings that govern how we throttle
+	 */
+	unsigned int wb_background;		/* background writeback */
+	unsigned int wb_normal;			/* normal writeback */
+	unsigned int wb_max;			/* max throughput writeback */
+	unsigned int scale_step;
+
+	u64 win_nsec;				/* default window size */
+	u64 cur_win_nsec;			/* current window size */
+
+	/*
+	 * Number of consecutive periods where we don't have enough
+	 * information to make a firm scale up/down decision.
+	 */
+	unsigned int unknown_cnt;
+
+	struct timer_list window_timer;
+
+	s64 sync_issue;
+	void *sync_cookie;
+
+	unsigned int wc;
+	unsigned int queue_depth;
+
+	unsigned long last_issue;		/* last non-throttled issue */
+	unsigned long last_comp;		/* last non-throttled comp */
+	unsigned long min_lat_nsec;
+	struct backing_dev_info *bdi;
+	struct request_queue *q;
+	wait_queue_head_t wait;
+	atomic_t inflight;
+
+	struct wb_stat_ops *stat_ops;
+	void *ops_data;
+};
+
+struct backing_dev_info;
+
+void __wbt_done(struct rq_wb *);
+void wbt_done(struct rq_wb *, struct wb_issue_stat *);
+bool wbt_wait(struct rq_wb *, unsigned int, spinlock_t *);
+struct rq_wb *wbt_init(struct backing_dev_info *, struct wb_stat_ops *, void *);
+void wbt_exit(struct rq_wb *);
+void wbt_update_limits(struct rq_wb *);
+void wbt_requeue(struct rq_wb *, struct wb_issue_stat *);
+void wbt_issue(struct rq_wb *, struct wb_issue_stat *);
+void wbt_disable(struct rq_wb *);
+
+void wbt_set_queue_depth(struct rq_wb *, unsigned int);
+void wbt_set_write_cache(struct rq_wb *, bool);
+
+#endif