Re: [PATCH] xen: ensure timer tick is resumed even on CPU driving the resume

[Shriram Rajagopalan <rshriram@gmail.com>]

[-- Attachment #1.1: Type: text/plain, Size: 2270 bytes --]

I know this is a long shot but is there an equivalent piece of code in the
2.6.18.8-xen kernel where this patch could be applied ? Assuming that the
2.6.18 also has a similar bug.

On Wed, May 19, 2010 at 11:02 AM, Jeremy Fitzhardinge <jeremy@goop.org>wrote:

> On 05/19/2010 08:36 AM, Ian Campbell wrote:
> > The core suspend/resume code is run from stop_machine on CPU0 but
> > parts of the suspend/resume machinery (including xen_arch_resume) are
> > run on whichever CPU happened to schedule the xenwatch kernel thread.
> >
> > As part of the non-core resume code xen_arch_resume is called in order
> > to restart the timer tick on non-boot processors. The boot processor
> > itself is taken care of by core timekeeping code.
> >
> > xen_arch_resume uses smp_call_function which does not call the given
> > function on the current processor. This means that we can end up with
> > one CPU not receiving timer ticks if the xenwatch thread happened to
> > be scheduled on CPU > 0.
> >
> > Use on_each_cpu instead of smp_call_function to ensure the timer tick
> > is resumed everywhere.
> >
>
> Argh, that seems to be a pretty common trap to fall into.  Looks OK (but
> unfortunately doesn't fix my other problem).
>
> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
>
>    J
>
> > Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> > Cc: Jeremy Fitzhardinge <jeremy@goop.org>
> > Cc: Stable Kernel <stable@kernel.org>
> > ---
> >  arch/x86/xen/suspend.c |    4 ++--
> >  1 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
> > index 987267f..a9c6611 100644
> > --- a/arch/x86/xen/suspend.c
> > +++ b/arch/x86/xen/suspend.c
> > @@ -60,6 +60,6 @@ static void xen_vcpu_notify_restore(void *data)
> >
> >  void xen_arch_resume(void)
> >  {
> > -     smp_call_function(xen_vcpu_notify_restore,
> > -                            (void *)CLOCK_EVT_NOTIFY_RESUME, 1);
> > +     on_each_cpu(xen_vcpu_notify_restore,
> > +                 (void *)CLOCK_EVT_NOTIFY_RESUME, 1);
> >  }
> >
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>



-- 
perception is but an offspring of its own self

[-- Attachment #1.2: Type: text/html, Size: 3235 bytes --]

[-- Attachment #2: Type: text/plain, Size: 138 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel