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Date: Thu, 13 Dec 2007 22:52:19 -0600 (CST)
From: Milton Miller <miltonm@bga.com>
Sender: Milton Miller <miltonm@realtime.net>
To: Paul Mackerras <paulus@samba.org>
Subject: [PATCH 5/6] depend on ->initialized in calc_steal_time
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If CPU_FTR_PURR is not set, we will never set cpu_purr_data->initialized.
Checking via __get_cpu_var on 64 bit avoids one dependent load compared
to cpu_has_feature in the not present case, and is always required when
it is present.  The code is under CONFIG_VIRT_CPU_ACCOUNTING so 32 bit
will not be affected.

Signed-off-by: Milton Miller <miltonm@bga.com>
---
Index: kernel/arch/powerpc/kernel/time.c
===================================================================
--- kernel.orig/arch/powerpc/kernel/time.c	2007-12-13 18:16:10.000000000 -0600
+++ kernel/arch/powerpc/kernel/time.c	2007-12-13 18:23:55.000000000 -0600
@@ -329,11 +329,9 @@ void calculate_steal_time(void)
 	s64 stolen;
 	struct cpu_purr_data *pme;
 
-	if (!cpu_has_feature(CPU_FTR_PURR))
-		return;
 	pme = &__get_cpu_var(cpu_purr_data);
 	if (!pme->initialized)
-		return;		/* this can happen in early boot */
+		return;		/* !CPU_FTR_PURR or early in early boot */
 	tb = mftb();
 	purr = mfspr(SPRN_PURR);
 	stolen = (tb - pme->tb) - (purr - pme->purr);