Re: linux-next: tip tree build warnings

From: Heiko Carstens
Date: Thu Sep 03 2009 - 08:24:53 EST


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@xxxxxxxxxxxxxxxx> 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? ;)
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