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, 6 deletions

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 5cd3db5cae41..3b26fbd6bec9 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -66,6 +66,7 @@
 #include <asm/smp.h>
 #include <asm/vdso_datapage.h>
 #include <asm/firmware.h>
+#include <asm/cputime.h>
 #ifdef CONFIG_PPC_ISERIES
 #include <asm/iseries/it_lp_queue.h>
 #include <asm/iseries/hv_call_xm.h>
@@ -189,6 +190,8 @@ u64 __cputime_sec_factor;
 EXPORT_SYMBOL(__cputime_sec_factor);
 u64 __cputime_clockt_factor;
 EXPORT_SYMBOL(__cputime_clockt_factor);
+DEFINE_PER_CPU(unsigned long, cputime_last_delta);
+DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta);
 
 static void calc_cputime_factors(void)
 {
@@ -257,8 +260,8 @@ void account_system_vtime(struct task_struct *tsk)
         }
         account_system_time(tsk, 0, delta);
         account_system_time_scaled(tsk, deltascaled);
-        get_paca()->purrdelta = delta;
-        get_paca()->spurrdelta = deltascaled;
+        per_cpu(cputime_last_delta, smp_processor_id()) = delta;
+        per_cpu(cputime_scaled_last_delta, smp_processor_id()) = deltascaled;
         local_irq_restore(flags);
 }
 
@@ -276,10 +279,7 @@ void account_process_tick(struct task_struct *tsk, int user_tick)
         get_paca()->user_time = 0;
         account_user_time(tsk, utime);
 
-        /* Estimate the scaled utime by scaling the real utime based
-         * on the last spurr to purr ratio */
-        utimescaled = utime * get_paca()->spurrdelta / get_paca()->purrdelta;
-        get_paca()->spurrdelta = get_paca()->purrdelta = 0;
+        utimescaled = cputime_to_scaled(utime);
         account_user_time_scaled(tsk, utimescaled);
 }