linux-next: tip tree build warnings

linux-next: tip tree build warnings

[Stephen Rothwell]

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Hi all,

Today's linux-next build (powerpc ppc64_defconfig) produced these warning:

In file included from include/trace/ftrace.h:285,
                 from include/trace/define_trace.h:61,
                 from include/trace/events/timer.h:342,
                 from kernel/timer.c:50:
include/trace/events/timer.h: In function 'ftrace_raw_output_itimer_state':
include/trace/events/timer.h:280: warning: format '%lu' expects type 'long unsigned int', but argument 4 has type 'cputime_t'
include/trace/events/timer.h: In function 'ftrace_raw_output_itimer_expire':
include/trace/events/timer.h:317: warning: format '%lu' expects type 'long unsigned int', but argument 5 has type 'cputime_t'

Introduced by commit 3f0a525ebf4b8ef041a332bbe4a73aee94bb064b ("timers: Add tracepoints for itimer") from the tip tree.

cputime_t is variously "u64", "unsigned long long" and "unsigned long" on
different architectures.

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

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Re: linux-next: tip tree build warnings

[Ingo Molnar]

* Stephen Rothwell <sfr@canb.auug.org.au> wrote:

> Hi all,
> 
> Today's linux-next build (powerpc ppc64_defconfig) produced these warning:
> 
> In file included from include/trace/ftrace.h:285,
>                  from include/trace/define_trace.h:61,
>                  from include/trace/events/timer.h:342,
>                  from kernel/timer.c:50:
> include/trace/events/timer.h: In function 'ftrace_raw_output_itimer_state':
> include/trace/events/timer.h:280: warning: format '%lu' expects type 'long unsigned int', but argument 4 has type 'cputime_t'
> include/trace/events/timer.h: In function 'ftrace_raw_output_itimer_expire':
> include/trace/events/timer.h:317: warning: format '%lu' expects type 'long unsigned int', but argument 5 has type 'cputime_t'

Should be harmless with no runtime effects - the fix would be to 
harmonize the cputime_t types across architectures.

> Introduced by commit 3f0a525ebf4b8ef041a332bbe4a73aee94bb064b ("timers: Add tracepoints for itimer") from the tip tree.
> 
> cputime_t is variously "u64", "unsigned long long" and "unsigned 
> long" on different architectures.

Should be unsigned long i think. Most architectures use it as 
unsigned long via include/asm-generic/cputime.h, except these three:

 arch/ia64/include/asm/cputime.h:typedef u64 cputime_t;
 arch/powerpc/include/asm/cputime.h:typedef u64 cputime_t;
 arch/s390/include/asm/cputime.h:typedef unsigned long long cputime_t;

Or we could eliminate the type altogether as well and standardize on 
u64. Thomas?

	Ingo

Re: linux-next: tip tree build warnings

[Heiko Carstens]

On Thu, Sep 03, 2009 at 10:38:44AM +0200, Ingo Molnar wrote:
> * Stephen Rothwell <sfr@canb.auug.org.au> wrote:
> > Today's linux-next build (powerpc ppc64_defconfig) produced these warning:
> > 
> > In file included from include/trace/ftrace.h:285,
> >                  from include/trace/define_trace.h:61,
> >                  from include/trace/events/timer.h:342,
> >                  from kernel/timer.c:50:
> > include/trace/events/timer.h: In function 'ftrace_raw_output_itimer_state':
> > include/trace/events/timer.h:280: warning: format '%lu' expects type 'long unsigned int', but argument 4 has type 'cputime_t'
> > include/trace/events/timer.h: In function 'ftrace_raw_output_itimer_expire':
> > include/trace/events/timer.h:317: warning: format '%lu' expects type 'long unsigned int', but argument 5 has type 'cputime_t'
> 
> Should be harmless with no runtime effects - the fix would be to 
> harmonize the cputime_t types across architectures.
> 
> > Introduced by commit 3f0a525ebf4b8ef041a332bbe4a73aee94bb064b ("timers: Add tracepoints for itimer") from the tip tree.
> > 
> > cputime_t is variously "u64", "unsigned long long" and "unsigned 
> > long" on different architectures.
> 
> Should be unsigned long i think. Most architectures use it as 
> unsigned long via include/asm-generic/cputime.h, except these three:
> 
>  arch/ia64/include/asm/cputime.h:typedef u64 cputime_t;
>  arch/powerpc/include/asm/cputime.h:typedef u64 cputime_t;
>  arch/s390/include/asm/cputime.h:typedef unsigned long long cputime_t;
> 
> Or we could eliminate the type altogether as well and standardize on 
> u64. Thomas?

s390 uses 64 bit cputime_t because we want the high resolution also in
32 bit kernels. So standardizing on u64 would be the preferred solution
for us.

Re: linux-next: tip tree build warnings

[Heiko Carstens]

On Thu, Sep 03, 2009 at 02:13:26PM +0200, Heiko Carstens wrote:
> On Thu, Sep 03, 2009 at 10:38:44AM +0200, Ingo Molnar wrote:
> > * Stephen Rothwell <sfr@canb.auug.org.au> wrote:
> > > Today's linux-next build (powerpc ppc64_defconfig) produced these warning:
> > > 
> > > In file included from include/trace/ftrace.h:285,
> > >                  from include/trace/define_trace.h:61,
> > >                  from include/trace/events/timer.h:342,
> > >                  from kernel/timer.c:50:
> > > include/trace/events/timer.h: In function 'ftrace_raw_output_itimer_state':
> > > include/trace/events/timer.h:280: warning: format '%lu' expects type 'long unsigned int', but argument 4 has type 'cputime_t'
> > > include/trace/events/timer.h: In function 'ftrace_raw_output_itimer_expire':
> > > include/trace/events/timer.h:317: warning: format '%lu' expects type 'long unsigned int', but argument 5 has type 'cputime_t'
> > 
> > Should be harmless with no runtime effects - the fix would be to 
> > harmonize the cputime_t types across architectures.
> > 
> > > Introduced by commit 3f0a525ebf4b8ef041a332bbe4a73aee94bb064b ("timers: Add tracepoints for itimer") from the tip tree.
> > > 
> > > cputime_t is variously "u64", "unsigned long long" and "unsigned 
> > > long" on different architectures.
> > 
> > Should be unsigned long i think. Most architectures use it as 
> > unsigned long via include/asm-generic/cputime.h, except these three:
> > 
> >  arch/ia64/include/asm/cputime.h:typedef u64 cputime_t;
> >  arch/powerpc/include/asm/cputime.h:typedef u64 cputime_t;
> >  arch/s390/include/asm/cputime.h:typedef unsigned long long cputime_t;
> > 
> > Or we could eliminate the type altogether as well and standardize on 
> > u64. Thomas?
> 
> s390 uses 64 bit cputime_t because we want the high resolution also in
> 32 bit kernels. So standardizing on u64 would be the preferred solution
> for us.

Alternatively the tracepoints could simply use cputime_to_cputime64.
But that would be too easy I guess? ;)

Re: linux-next: tip tree build warnings

[Martin Schwidefsky]

On Thu, 3 Sep 2009 14:13:26 +0200
Heiko Carstens <heiko.carstens@de.ibm.com> wrote:

> On Thu, Sep 03, 2009 at 10:38:44AM +0200, Ingo Molnar wrote:
> > * Stephen Rothwell <sfr@canb.auug.org.au> wrote:
> > > cputime_t is variously "u64", "unsigned long long" and "unsigned 
> > > long" on different architectures.
> > 
> > Should be unsigned long i think. Most architectures use it as 
> > unsigned long via include/asm-generic/cputime.h, except these three:
> > 
> >  arch/ia64/include/asm/cputime.h:typedef u64 cputime_t;
> >  arch/powerpc/include/asm/cputime.h:typedef u64 cputime_t;
> >  arch/s390/include/asm/cputime.h:typedef unsigned long long cputime_t;
> > 
> > Or we could eliminate the type altogether as well and standardize on 
> > u64. Thomas?
> 
> s390 uses 64 bit cputime_t because we want the high resolution also in
> 32 bit kernels. So standardizing on u64 would be the preferred solution
> for us.

The cputime_t type serves/served two purposes: 1) make it clear that
this is NOT a jiffie value, it is an architecture defined type with
architecture dependent semantic, 2) by redefining cputime_t to a
structure with a single embedded unsigned long I have been able to
identify all places in the kernel that do not use the proper cputime
functions. I'm not sure if we need 2) anymore.

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.