57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
|
|
||
|
|
#include <linux/wait.h>
|
||
|
|
#include <linux/backing-dev.h>
|
||
|
|
#include <linux/fs.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/module.h>
|
||
|
|
|
||
|
|
static wait_queue_head_t congestion_wqh[2] = {
|
||
|
|
__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
|
||
|
|
__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
void clear_bdi_congested(struct backing_dev_info *bdi, int rw)
|
||
|
|
{
|
||
|
|
enum bdi_state bit;
|
||
|
|
wait_queue_head_t *wqh = &congestion_wqh[rw];
|
||
|
|
|
||
|
|
bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
|
||
|
|
clear_bit(bit, &bdi->state);
|
||
|
|
smp_mb__after_clear_bit();
|
||
|
|
if (waitqueue_active(wqh))
|
||
|
|
wake_up(wqh);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(clear_bdi_congested);
|
||
|
|
|
||
|
|
void set_bdi_congested(struct backing_dev_info *bdi, int rw)
|
||
|
|
{
|
||
|
|
enum bdi_state bit;
|
||
|
|
|
||
|
|
bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
|
||
|
|
set_bit(bit, &bdi->state);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(set_bdi_congested);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* congestion_wait - wait for a backing_dev to become uncongested
|
||
|
|
* @rw: READ or WRITE
|
||
|
|
* @timeout: timeout in jiffies
|
||
|
|
*
|
||
|
|
* Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit
|
||
|
|
* write congestion. If no backing_devs are congested then just wait for the
|
||
|
|
* next write to be completed.
|
||
|
|
*/
|
||
|
|
long congestion_wait(int rw, long timeout)
|
||
|
|
{
|
||
|
|
long ret;
|
||
|
|
DEFINE_WAIT(wait);
|
||
|
|
wait_queue_head_t *wqh = &congestion_wqh[rw];
|
||
|
|
|
||
|
|
prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
|
||
|
|
ret = io_schedule_timeout(timeout);
|
||
|
|
finish_wait(wqh, &wait);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(congestion_wait);
|