Re: [RFC][PATCH] sched_clock_cpu()

[David Miller <davem@davemloft.net>]

From: Ingo Molnar <mingo@elte.hu>
Date: Sat, 3 May 2008 19:01:30 +0200

> 
> * Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> 
> > it _DOESN'T_ boot ;-/ and I seem to have caught a flu that makes my
> > whole body hurt like hell, so I'm not getting anything done.
> 
> i think i see where your boot problem comes from:
> 
> > +struct sched_clock_data {
> > +	spinlock_t lock;
> 
> that wont work very well when sched_clock() is called from within 
> CONFIG_LOCK_STAT instrumentation. Does the patch below solve the boot 
> problems for you?

Also, no platform can set HAVE_STABLE_CLOCK until we instantiate it in
a Kconfig somewhere.  I've choosen to do it in kernel/Kconfig.hz and
here are the sparc/sparc64 bits as well, I've booted this up with
Peter's patch on my 64-cpu niagara2 box and done some basic testing.

It would be nice if a powerpc person could test the trivial
powerpc Kconfig patch.

Possibly this should be HAVE_UNSTABLE_CLOCK, then only one platform
needs to set it :-)

sparc: Instantiate and set HAVE_STABLE_CLOCK

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index d211fdb..c60f5d4 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -69,6 +69,7 @@ config SPARC
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_ARCH_KGDB if !SMP
+	select HAVE_STABLE_CLOCK
 
 # Identify this as a Sparc32 build
 config SPARC32
diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
index eb36f3b..711d4b1 100644
--- a/arch/sparc64/Kconfig
+++ b/arch/sparc64/Kconfig
@@ -14,6 +14,7 @@ config SPARC64
 	select HAVE_IDE
 	select HAVE_LMB
 	select HAVE_ARCH_KGDB
+	select HAVE_STABLE_CLOCK
 
 config GENERIC_TIME
 	bool
diff --git a/kernel/Kconfig.hz b/kernel/Kconfig.hz
index 526128a..b88c82a 100644
--- a/kernel/Kconfig.hz
+++ b/kernel/Kconfig.hz
@@ -56,3 +56,6 @@ config HZ
 
 config SCHED_HRTICK
 	def_bool HIGH_RES_TIMERS && X86
+
+config HAVE_STABLE_CLOCK
+	boolean