2015-11-09 17:36:43

by Peter Zijlstra

Subject: Re: [PATCH v11 2/5] missing include asm/paravirt.h in cputime.c

On Thu, Nov 05, 2015 at 05:30:01PM +0000, Stefano Stabellini wrote:
> On Thu, 5 Nov 2015, Peter Zijlstra wrote:
> > How can this be missing? Things compile fine now, right?
>
> Fair enough.
>
>
> > So please better explain why we do this change.
>
> asm/paravirt.h is included by one of the other headers included in
> kernel/sched/cputime.c on x86, but not on other architecures. On arm and
> arm64, where I am about to introduce asm/paravirt.h and stolen time
> support, without #include <asm/paravirt.h> in cputime.c I would get:
>
> kernel/sched/cputime.c: In function ‘steal_account_process_tick’:
> kernel/sched/cputime.c:260:24: error: ‘paravirt_steal_enabled’ undeclared (first use in this function)
> if (static_key_false(&paravirt_steal_enabled)) {
>
> A bit of digging on x86 (using gcc -E on cputime.c) tells me that
> asm/paravirt.h is coming from the following include chain:
>
> #include <kernel/sched/sched.h>
> #include <linux/spinlock.h>
> #include <linux/preempt.h>
> #include <asm/preempt.h>
> #include <linux/thread_info.h>
> #include <asm/thread_info.h>
> #include <asm/processor.h>
> #include <asm/msr.h>
> #include <asm/paravirt.h>


Fair enough; a slightly shorter version of that for a changelog will do
nicely.

Thanks!

2015-11-10 11:27:51

by Stefano Stabellini

Subject: Re: [PATCH v11 2/5] missing include asm/paravirt.h in cputime.c

On Mon, 9 Nov 2015, Peter Zijlstra wrote:
> On Thu, Nov 05, 2015 at 05:30:01PM +0000, Stefano Stabellini wrote:
> > On Thu, 5 Nov 2015, Peter Zijlstra wrote:
> > > How can this be missing? Things compile fine now, right?
> >
> > Fair enough.
> >
> >
> > > So please better explain why we do this change.
> >
> > asm/paravirt.h is included by one of the other headers included in
> > kernel/sched/cputime.c on x86, but not on other architecures. On arm and
> > arm64, where I am about to introduce asm/paravirt.h and stolen time
> > support, without #include <asm/paravirt.h> in cputime.c I would get:
> >
> > kernel/sched/cputime.c: In function ‘steal_account_process_tick’:
> > kernel/sched/cputime.c:260:24: error: ‘paravirt_steal_enabled’ undeclared (first use in this function)
> > if (static_key_false(&paravirt_steal_enabled)) {
> >
> > A bit of digging on x86 (using gcc -E on cputime.c) tells me that
> > asm/paravirt.h is coming from the following include chain:
> >
> > #include <kernel/sched/sched.h>
> > #include <linux/spinlock.h>
> > #include <linux/preempt.h>
> > #include <asm/preempt.h>
> > #include <linux/thread_info.h>
> > #include <asm/thread_info.h>
> > #include <asm/processor.h>
> > #include <asm/msr.h>
> > #include <asm/paravirt.h>
>
>
> Fair enough; a slightly shorter version of that for a changelog will do
> nicely.

Sure. Can I add your Acked-by to it?

2015-11-10 12:19:19

by Peter Zijlstra

Subject: Re: [PATCH v11 2/5] missing include asm/paravirt.h in cputime.c

On Tue, Nov 10, 2015 at 11:27:33AM +0000, Stefano Stabellini wrote:
> On Mon, 9 Nov 2015, Peter Zijlstra wrote:
> > On Thu, Nov 05, 2015 at 05:30:01PM +0000, Stefano Stabellini wrote:
> > > On Thu, 5 Nov 2015, Peter Zijlstra wrote:
> > > > How can this be missing? Things compile fine now, right?
> > >
> > > Fair enough.
> > >
> > >
> > > > So please better explain why we do this change.
> > >
> > > asm/paravirt.h is included by one of the other headers included in
> > > kernel/sched/cputime.c on x86, but not on other architecures. On arm and
> > > arm64, where I am about to introduce asm/paravirt.h and stolen time
> > > support, without #include <asm/paravirt.h> in cputime.c I would get:
> > >
> > > kernel/sched/cputime.c: In function ‘steal_account_process_tick’:
> > > kernel/sched/cputime.c:260:24: error: ‘paravirt_steal_enabled’ undeclared (first use in this function)
> > > if (static_key_false(&paravirt_steal_enabled)) {
> > >
> > > A bit of digging on x86 (using gcc -E on cputime.c) tells me that
> > > asm/paravirt.h is coming from the following include chain:
> > >
> > > #include <kernel/sched/sched.h>
> > > #include <linux/spinlock.h>
> > > #include <linux/preempt.h>
> > > #include <asm/preempt.h>
> > > #include <linux/thread_info.h>
> > > #include <asm/thread_info.h>
> > > #include <asm/processor.h>
> > > #include <asm/msr.h>
> > > #include <asm/paravirt.h>
> >
> >
> > Fair enough; a slightly shorter version of that for a changelog will do
> > nicely.
>
> Sure. Can I add your Acked-by to it?

Yep, no objection if the changelog is updated as per the above.

Acked-by: Peter Zijlstra (Intel) <[email protected]>