The commit fa13a5a1f25f671d084d8884be96fc48d9b68275, unconditionally calls

update_process_tick() in system context.  In the deterministic accounting case

this is the correct thing to do.  However, in the non-deterministic accounting

case we need to not do this, and results in the time accounted as

hardware irq time being artificially elevated.
Also this patch collapses 2 consecutive '#ifdef CONFIG_VIRT_CPU_ACCOUNTING'

checks in time.h into for neatness.
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>

---

The problem was seen and reported by Johannes Berg  and Frederik Himpe.

Paul, I think this is good for 2.6.24.
 arch/powerpc/kernel/process.c |    2 +-

 include/asm-powerpc/time.h    |   12 ++++--------

 2 files changed, 5 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c

index 41e13f4..b9d8837 100644

--- a/arch/powerpc/kernel/process.c

+++ b/arch/powerpc/kernel/process.c

@@ -350,7 +350,7 @@ struct task_struct *__switch_to(struct task_struct *prev,

 	local_irq_save(flags);
 	account_system_vtime(current);

-	account_process_tick(current, 0);

+	account_process_vtime(current);

 	calculate_steal_time();
 	last = _switch(old_thread, new_thread);

diff --git a/include/asm-powerpc/time.h b/include/asm-powerpc/time.h

index 780f826..8a2c8db 100644

--- a/include/asm-powerpc/time.h

+++ b/include/asm-powerpc/time.h

@@ -237,18 +237,14 @@ struct cpu_usage {
 DECLARE_PER_CPU(struct cpu_usage, cpu_usage_array);
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING

-extern void account_process_vtime(struct task_struct *tsk);

-#else

-#define account_process_vtime(tsk)		do { } while (0)

-#endif

-

 #if defined(CONFIG_VIRT_CPU_ACCOUNTING)

 extern void calculate_steal_time(void);

 extern void snapshot_timebases(void);

+#define account_process_vtime(tsk)	account_process_tick(current, 0);

 #else

-#define calculate_steal_time()			do { } while (0)

-#define snapshot_timebases()			do { } while (0)

+#define calculate_steal_time()		...
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