summaryrefslogtreecommitdiffstats
path: root/block/blk-wbt.h
diff options
context:
space:
mode:
Diffstat (limited to 'block/blk-wbt.h')
-rw-r--r--block/blk-wbt.h134
1 files changed, 134 insertions, 0 deletions
diff --git a/block/blk-wbt.h b/block/blk-wbt.h
new file mode 100644
index 000000000..2eb01becd
--- /dev/null
+++ b/block/blk-wbt.h
@@ -0,0 +1,134 @@
+/* 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 void wbt_track(struct request *rq, enum wbt_flags flags)
+{
+}
+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