Re: excessive kworker activity when idle. (was Re: vma corruption in today's -git)

Dave Jones
2011-03-31T15:50:24Z

On Thu, Mar 31, 2011 at 08:25:36AM -0700, Linus Torvalds wrote:
> On Thu, Mar 31, 2011 at 8:03 AM, Dave Jones <davej@redhat.com> wrote:
> > On Thu, Mar 31, 2011 at 10:58:50AM -0400, Dave Jones wrote:
> >
> > bah I missed a level. which seems to be the smoking gun.
> > something in the tty layer seems to have gone nuts.
>
> Ahhah. That is indeed the smoking gun.
>
> I bet it's an old problem where something causes some stupid tty
> ping-pong behaviour, and now it has become a high-CPU thing triggered
> by commit f23eb2b2b285 ("tty: stop using "delayed_work" in the tty
> layer").
>
> Before that commit, if the tty layer got somehow confused, it would
> always delay for a timer tick in between doing nothing. Now it will go
> pretty much full blast. Which explains your CPU being hot.

That's a recent change though, and I first saw this back in November.

Dave