diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm-cache-target.c | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index d598248..6f9bdd1 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -25,6 +25,79 @@ DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, /*----------------------------------------------------------------*/ +#define IOT_RESOLUTION 4 + +struct io_tracker { + spinlock_t lock; + + /* + * Sectors of in-flight IO. + */ + sector_t in_flight; + + /* + * The time, in jiffies, when this device became idle (if it is + * indeed idle). + */ + unsigned long idle_time; + unsigned long last_update_time; +}; + +static void iot_init(struct io_tracker *iot) +{ + spin_lock_init(&iot->lock); + iot->in_flight = 0ul; + iot->idle_time = 0ul; + iot->last_update_time = jiffies; +} + +static bool __iot_idle_for(struct io_tracker *iot, unsigned long jifs) +{ + if (iot->in_flight) + return false; + + return time_after(jiffies, iot->idle_time + jifs); +} + +static bool iot_idle_for(struct io_tracker *iot, unsigned long jifs) +{ + bool r; + unsigned long flags; + + spin_lock_irqsave(&iot->lock, flags); + r = __iot_idle_for(iot, jifs); + spin_unlock_irqrestore(&iot->lock, flags); + + return r; +} + +static void iot_io_begin(struct io_tracker *iot, sector_t len) +{ + unsigned long flags; + + spin_lock_irqsave(&iot->lock, flags); + iot->in_flight += len; + spin_unlock_irqrestore(&iot->lock, flags); +} + +static void __iot_io_end(struct io_tracker *iot, sector_t len) +{ + iot->in_flight -= len; + if (!iot->in_flight) + iot->idle_time = jiffies; +} + +static void iot_io_end(struct io_tracker *iot, sector_t len) +{ + unsigned long flags; + + spin_lock_irqsave(&iot->lock, flags); + __iot_io_end(iot, len); + spin_unlock_irqrestore(&iot->lock, flags); +} + +/*----------------------------------------------------------------*/ + /* * Glossary: * |