drivers/md/dm-io-tracker.h

0001 /*
0002  * Copyright (C) 2021 Red Hat, Inc. All rights reserved.
0003  *
0004  * This file is released under the GPL.
0005  */
0006
0007 #ifndef DM_IO_TRACKER_H
0008 #define DM_IO_TRACKER_H
0009
0010 #include <linux/jiffies.h>
0011
0012 struct dm_io_tracker {
0013     spinlock_t lock;
0014
0015     /*
0016      * Sectors of in-flight IO.
0017      */
0018     sector_t in_flight;
0019
0020     /*
0021      * The time, in jiffies, when this device became idle
0022      * (if it is indeed idle).
0023      */
0024     unsigned long idle_time;
0025     unsigned long last_update_time;
0026 };
0027
0028 static inline void dm_iot_init(struct dm_io_tracker *iot)
0029 {
0030     spin_lock_init(&iot->lock);
0031     iot->in_flight = 0ul;
0032     iot->idle_time = 0ul;
0033     iot->last_update_time = jiffies;
0034 }
0035
0036 static inline bool dm_iot_idle_for(struct dm_io_tracker *iot, unsigned long j)
0037 {
0038     bool r = false;
0039
0040     spin_lock_irq(&iot->lock);
0041     if (!iot->in_flight)
0042         r = time_after(jiffies, iot->idle_time + j);
0043     spin_unlock_irq(&iot->lock);
0044
0045     return r;
0046 }
0047
0048 static inline unsigned long dm_iot_idle_time(struct dm_io_tracker *iot)
0049 {
0050     unsigned long r = 0;
0051
0052     spin_lock_irq(&iot->lock);
0053     if (!iot->in_flight)
0054         r = jiffies - iot->idle_time;
0055     spin_unlock_irq(&iot->lock);
0056
0057     return r;
0058 }
0059
0060 static inline void dm_iot_io_begin(struct dm_io_tracker *iot, sector_t len)
0061 {
0062     spin_lock_irq(&iot->lock);
0063     iot->in_flight += len;
0064     spin_unlock_irq(&iot->lock);
0065 }
0066
0067 static inline void dm_iot_io_end(struct dm_io_tracker *iot, sector_t len)
0068 {
0069     unsigned long flags;
0070
0071     if (!len)
0072         return;
0073
0074     spin_lock_irqsave(&iot->lock, flags);
0075     iot->in_flight -= len;
0076     if (!iot->in_flight)
0077         iot->idle_time = jiffies;
0078     spin_unlock_irqrestore(&iot->lock, flags);
0079 }
0080
0081 #endif