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#include "bcache.h"
#include "clock.h"
#include <linux/freezer.h>
#include <linux/kthread.h>
static inline bool io_timer_cmp(struct io_timer *l, struct io_timer *r)
{
return time_after(l->expire, r->expire);
}
void bch_io_timer_add(struct io_clock *clock, struct io_timer *timer)
{
size_t i;
spin_lock(&clock->timer_lock);
for (i = 0; i < clock->timers.used; i++)
if (clock->timers.data[i] == timer)
goto out;
BUG_ON(!heap_add(&clock->timers, timer, io_timer_cmp));
out:
spin_unlock(&clock->timer_lock);
}
void bch_io_timer_del(struct io_clock *clock, struct io_timer *timer)
{
size_t i;
spin_lock(&clock->timer_lock);
for (i = 0; i < clock->timers.used; i++)
if (clock->timers.data[i] == timer) {
heap_del(&clock->timers, i, io_timer_cmp);
break;
}
spin_unlock(&clock->timer_lock);
}
struct io_clock_wait {
struct io_timer timer;
struct task_struct *task;
int expired;
};
static void io_clock_wait_fn(struct io_timer *timer)
{
struct io_clock_wait *wait = container_of(timer,
struct io_clock_wait, timer);
wait->expired = 1;
wake_up_process(wait->task);
}
void bch_io_clock_schedule_timeout(struct io_clock *clock, unsigned long until)
{
struct io_clock_wait wait;
/* XXX: calculate sleep time rigorously */
wait.timer.expire = until;
wait.timer.fn = io_clock_wait_fn;
wait.task = current;
wait.expired = 0;
bch_io_timer_add(clock, &wait.timer);
schedule();
bch_io_timer_del(clock, &wait.timer);
}
/*
* _only_ to be used from a kthread
*/
void bch_kthread_io_clock_wait(struct io_clock *clock,
unsigned long until)
{
struct io_clock_wait wait;
/* XXX: calculate sleep time rigorously */
wait.timer.expire = until;
wait.timer.fn = io_clock_wait_fn;
wait.task = current;
wait.expired = 0;
bch_io_timer_add(clock, &wait.timer);
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop())
break;
if (wait.expired)
break;
schedule();
try_to_freeze();
}
__set_current_state(TASK_RUNNING);
bch_io_timer_del(clock, &wait.timer);
}
static struct io_timer *get_expired_timer(struct io_clock *clock,
unsigned long now)
{
struct io_timer *ret = NULL;
spin_lock(&clock->timer_lock);
if (clock->timers.used &&
time_after_eq(now, clock->timers.data[0]->expire))
heap_pop(&clock->timers, ret, io_timer_cmp);
spin_unlock(&clock->timer_lock);
return ret;
}
void bch_increment_clock(struct cache_set *c, unsigned sectors, int rw)
{
struct io_clock *clock = &c->io_clock[rw];
struct io_timer *timer;
unsigned long now;
/* Buffer up one megabyte worth of IO in the percpu counter */
preempt_disable();
if (likely(this_cpu_add_return(*clock->pcpu_buf, sectors) <
IO_CLOCK_PCPU_SECTORS)) {
preempt_enable();
return;
}
sectors = this_cpu_xchg(*clock->pcpu_buf, 0);
preempt_enable();
now = atomic_long_add_return(sectors, &clock->now);
while ((timer = get_expired_timer(clock, now)))
timer->fn(timer);
}
void bch_io_clock_exit(struct io_clock *clock)
{
free_heap(&clock->timers);
free_percpu(clock->pcpu_buf);
}
int bch_io_clock_init(struct io_clock *clock)
{
atomic_long_set(&clock->now, 0);
spin_lock_init(&clock->timer_lock);
clock->pcpu_buf = alloc_percpu(*clock->pcpu_buf);
if (!clock->pcpu_buf)
return -ENOMEM;
if (!init_heap(&clock->timers, NR_IO_TIMERS, GFP_KERNEL))
return -ENOMEM;
return 0;
}
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