Re: [PULL}: latest tip/cpus4096 changes

From: Ingo Molnar
Date: Fri Jan 16 2009 - 17:32:28 EST



* Mike Travis <travis@xxxxxxx> wrote:

> Ingo Molnar wrote:
> > * Mike Travis <travis@xxxxxxx> wrote:
> >
> >> commit b758cdbee5da0b8fb7e34a68651e6ccc5310b48a
> >> Author: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> >> Date: Thu Jan 15 16:29:16 2009 -0800
> >>
> >> work_on_cpu: Use our own workqueue.
> >>
> >> Impact: remove potential circular lock dependency with generic kevent workqueue
> >>
> >> Annoyingly, some places we want to use work_on_cpu are already in
> >> workqueues. As per Ingo's suggestion, we create a different workqueue
> >> for work_on_cpu.
> >
> > btw., that's a nice fix - were you able to reproduce any of the lockdep
> > asserts that i got in testing, and did those go away with this patch?
> >
> > If yes then that's nice and makes work_on_cpu() a lot more usable IMO.
> >
> > If not then that should generally be declared in the pull request:
> > "beware, different approach than before but might still trigger lockdep
> > warnings"
> >
> > Ingo
>
> Hi,
>
> I've been trying all sorts of overlapping testing and I've not gotten the
> lockdep warnings any more. (I do occasionally get that debug object warning
> that I mentioned to Thomas, though that comes and goes irregardless of any
> patches.) [...]

That hpet warning is fixed in tip/timers/urgent [which you wont have if
you try pure tip/cpus4096].

> [...] The two fixes that Rusty did (lose the get_online_cpus() and use
> a separate work queue) seems to have relieved work_on_cpu of it's
> primary problems, and I've not found any new ones to replace them yet.
> ;-)
>
> So I'll "un-push" the entire patchset, and then re-push the x86 only
> ones, and send the others to their respective maintainers after fixing
> the problems you mentioned. (Posting patches to the list was way more
> fun, and less "committable". ;-)

Sounds good.

Ingo
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