Re: [PATCH 08/09] tick/xen: Provide and use tick_suspend_local() and tick_resume_local()

From: Konrad Rzeszutek Wilk
Date: Wed Mar 25 2015 - 16:45:29 EST


On Wed, Mar 25, 2015 at 09:57:18PM +0100, Rafael J. Wysocki wrote:
> On Wednesday, March 25, 2015 04:13:09 PM Konrad Rzeszutek Wilk wrote:
> > On Wed, Mar 25, 2015 at 01:11:04PM +0100, Rafael J. Wysocki wrote:
> > > From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > >
> > > Xen calls on every cpu into tick_resume() which is just wrong.
> > > tick_resume() is for the syscore global suspend/resume invocation.
> > > What XEN really wants is a per cpu local resume function.
> > >
> > > Provide a tick_resume_local() function and use it in XEN.
> > >
> > > Also provide a complementary tick_suspend_local() and modify
> > > tick_unfreeze() and tick_freeze(), respectively, to use the
> > > new local tick resume/suspend functions.
> > >
> > > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > > Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> > > Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> > > Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
> > > [ rjw: Combined two patches, rebased, modified subject/changelog ]
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > > ---
> > > arch/x86/xen/suspend.c | 2 -
> > > include/linux/tick.h | 6 ++--
> > > kernel/time/tick-broadcast.c | 24 ++++++++++++------
> > > kernel/time/tick-common.c | 57 +++++++++++++++++++++++++++++--------------
> > > kernel/time/tick-internal.h | 8 ++++--
> > > 5 files changed, 66 insertions(+), 31 deletions(-)
> > >
> > > Index: linux-pm/arch/x86/xen/suspend.c
> > > ===================================================================
> > > --- linux-pm.orig/arch/x86/xen/suspend.c
> > > +++ linux-pm/arch/x86/xen/suspend.c
> > > @@ -85,7 +85,7 @@ static void xen_vcpu_notify_restore(void
> > > if (smp_processor_id() == 0)
> > > return;
> > >
> > > - tick_resume();
> > > + tick_resume_local();
> >
> > I am looking at Linus's tree and I see:
> >
> > 82 static void xen_vcpu_notify_restore(void *data)
> > 83 {
> > 84 unsigned long reason = (unsigned long)data;
> > 85
> > 86 /* Boot processor notified via generic timekeeping_resume() */
> > 87 if ( smp_processor_id() == 0)
> > 88 return;
> > 89
> > 90 clockevents_notify(reason, NULL);
> > 91 }
> >
> > So there must be another patch that altered the clockevents_notify?
>
> Yes, there is. It is the [06/09] in this series
> (https://patchwork.kernel.org/patch/6090631/).
>
> I should have CCed it to you too, sorry about that.

That is alright.
>
> > Is there an git tree with all of these patches?
>
> Not yet, but they all are in the linux-pm patchwork at
>
> https://patchwork.kernel.org/project/linux-pm/list/
>
> I can create a branch in the linux-pm.git tree for them if that helps,
> please let me know.

If it is not too much trouble..

Thank you.
>
>
> --
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.
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