taskstats scaled time cleanup

This moves the ability to scale cputime into generic code.  This allows us
to fix the issue in kernel/timer.c (noticed by Balbir) where we could only
add an unscaled value to the scaled utime/stime.

This adds a cputime_to_scaled function.  As before, the POWERPC version
does the scaling based on the last SPURR/PURR ratio calculated.  The
generic and s390 (only other arch to implement asm/cputime.h) versions are
both NOPs.

Also moves the SPURR and PURR snapshots closer.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/kernel/timer.c b/kernel/timer.c
index 9fbb472b8cf0..70b29b59343f 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -818,12 +818,14 @@ unsigned long next_timer_interrupt(void)
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
 void account_process_tick(struct task_struct *p, int user_tick)
 {
+        cputime_t one_jiffy = jiffies_to_cputime(1);
+
         if (user_tick) {
-                account_user_time(p, jiffies_to_cputime(1));
-                account_user_time_scaled(p, jiffies_to_cputime(1));
+                account_user_time(p, one_jiffy);
+                account_user_time_scaled(p, cputime_to_scaled(one_jiffy));
         } else {
-                account_system_time(p, HARDIRQ_OFFSET, jiffies_to_cputime(1));
-                account_system_time_scaled(p, jiffies_to_cputime(1));
+                account_system_time(p, HARDIRQ_OFFSET, one_jiffy);
+                account_system_time_scaled(p, cputime_to_scaled(one_jiffy));
         }
 }
 #endif