On Tue, 19 Dec 2006 03:43:19 +0300
Oleg Nesterov <[email protected]> wrote:
> On 12/18, Andrew Morton wrote:
> >
> > On Mon, 18 Dec 2006 01:34:16 +0300
> > Oleg Nesterov <[email protected]> wrote:
> >
> > > NOTE: I removed 'int cpu' parameter, flush_workqueue() locks/unlocks
> > > workqueue_mutex unconditionally. It may be restored, but I think it
> > > doesn't make much sense, we take the mutex for the very short time,
> > > and the code becomes simpler.
> > >
> >
> > Taking workqueue_mutex() unconditionally in flush_workqueue() means
> > that we'll deadlock if a single-threaded workqueue callback handler calls
> > flush_workqueue().
>
> Well. But flush_workqueue() drops workqueue_mutex before going to sleep ?
>
> flush_workqueue(single_threaded_wq);
> ...
> mutex_lock(&workqueue_mutex);
> ...
> mutex_unlock(&workqueue_mutex);
> wait_for_completition();
> handler runs,
> calls flush_workqueue(),
> workqueue_mutex is free
Oh. OK. In that case we can switch to preempt_disable() for the
cpu-hotplug holdoff. Sometime.
> > It's an idiotic thing to do, but I think I spotted a site last week which
> > does this. scsi? Not sure..
>
> Ok, it is time to sleep. I'll look tomorrov and re-send if flush_cpu_workqueue()
> really needs "bool workqueue_mutex_is_locked" parameter.
Hopefully not.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
