1 files changed, 131 insertions, 0 deletions
diff --git a/block/blk-wbt.h b/block/blk-wbt.h
new file mode 100644
index 000000000..7e44eccc6
--- /dev/null
+++ b/block/blk-wbt.h
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef WB_THROTTLE_H
+#define WB_THROTTLE_H
+
+#include <linux/kernel.h>
+#include <linux/atomic.h>
+#include <linux/wait.h>
+#include <linux/timer.h>
+#include <linux/ktime.h>
+
+#include "blk-stat.h"
+#include "blk-rq-qos.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,
+};
+
+/*
+ * Enable states. Either off, or on by default (done at init time),
+ * or on through manual setup in sysfs.
+ */
+enum {
+	WBT_STATE_ON_DEFAULT	= 1,
+	WBT_STATE_ON_MANUAL	= 2,
+	WBT_STATE_OFF_DEFAULT
+};
+
+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 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;
+}
+
+
+#ifdef CONFIG_BLK_WBT
+
+int wbt_init(struct request_queue *);
+void wbt_disable_default(struct request_queue *);
+void wbt_enable_default(struct request_queue *);
+
+u64 wbt_get_min_lat(struct request_queue *q);
+void wbt_set_min_lat(struct request_queue *q, u64 val);
+
+void wbt_set_write_cache(struct request_queue *, bool);
+
+u64 wbt_default_latency_nsec(struct request_queue *);
+
+#else
+
+static inline int wbt_init(struct request_queue *q)
+{
+	return -EINVAL;
+}
+static inline void wbt_disable_default(struct request_queue *q)
+{
+}
+static inline void wbt_enable_default(struct request_queue *q)
+{
+}
+static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
+{
+}
+static inline u64 wbt_get_min_lat(struct request_queue *q)
+{
+	return 0;
+}
+static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
+{
+}
+static inline u64 wbt_default_latency_nsec(struct request_queue *q)
+{
+	return 0;
+}
+
+#endif /* CONFIG_BLK_WBT */
+
+#endif