On 05/22/2012 08:58 PM, Dave Chinner wrote:
snip
>
> Finally, rather than calling wake_up_process() in the
> xfs_ail_push*() functions, call wake_up(&ailp->xa_idle); There can
> only be one thread sleeping on that (the xfsaild) so there is no
> need to use the wake_up_all() variant...
>
> FWIW, you might be able to do this without the idle wait queue and
> just use wake_up_process() -
>
Hi Dave,
I have a working version of your suggested algorithm. It looks mostly the same with the exception of a spin_unlock fix. I also have the below version that uses a wait_queue and that I plan to test overnight tonight:
while (!kthread_should_stop()) {
if (tout && tout <= 20)
state = TASK_KILLABLE;
else
state = TASK_INTERRUPTIBLE;
prepare_to_wait(&ailp->xa_idle, &wait, state);
spin_lock(&ailp->xa_lock);
/* barrier matches the xa_target update in xfs_ail_push() */
smp_rmb();
if (!xfs_ail_min(ailp) && (ailp->xa_target == ailp->xa_target_prev)) {
/* the ail is empty and no change to the push target - idle */
spin_unlock(&ailp->xa_lock);
schedule();
} else if (tout) {
spin_unlock(&ailp->xa_lock);
/* more work to do soon */
schedule_timeout(msecs_to_jiffies(tout));
} else {
spin_unlock(&ailp->xa_lock);
}
finish_wait(&ailp->xa_idle, &wait);
try_to_freeze();
tout = xfsaild_push(ailp);
}
... and obviously the xfs_ail_push() side changes to:
wake_up(&ailp->xa_idle);
Does this wait_queue version look sane to you? Thanks again..
Brian
> Cheers,
>
> Dave.
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