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>

4 files changed, 16 insertions, 2 deletions

diff --git a/include/asm-generic/cputime.h b/include/asm-generic/cputime.h
index 09204e4..1c1fa42 100644
--- a/include/asm-generic/cputime.h
+++ b/include/asm-generic/cputime.h
@@ -18,6 +18,7 @@ typedef unsigned long cputime_t;
 #define cputime_lt(__a, __b)		((__a) <  (__b))
 #define cputime_le(__a, __b)		((__a) <= (__b))
 #define cputime_to_jiffies(__ct)	(__ct)
+#define cputime_to_scaled(__ct)		(__ct)
 #define jiffies_to_cputime(__hz)	(__hz)
 
 typedef u64 cputime64_t;
diff --git a/include/asm-powerpc/cputime.h b/include/asm-powerpc/cputime.h
index 3108044..f42e623 100644
--- a/include/asm-powerpc/cputime.h
+++ b/include/asm-powerpc/cputime.h
@@ -52,12 +52,26 @@ typedef u64 cputime64_t;
  * Convert cputime <-> jiffies
  */
 extern u64 __cputime_jiffies_factor;
+DECLARE_PER_CPU(unsigned long, cputime_last_delta);
+DECLARE_PER_CPU(unsigned long, cputime_scaled_last_delta);
 
 static inline unsigned long cputime_to_jiffies(const cputime_t ct)
 {
 	return mulhdu(ct, __cputime_jiffies_factor);
 }
 
+/* Estimate the scaled cputime by scaling the real cputime based on
+ * the last scaled to real ratio */
+static inline cputime_t cputime_to_scaled(const cputime_t ct)
+{
+	if (cpu_has_feature(CPU_FTR_SPURR) &&
+	    per_cpu(cputime_last_delta, smp_processor_id()))
+		return ct *
+			per_cpu(cputime_scaled_last_delta, smp_processor_id())/
+			per_cpu(cputime_last_delta, smp_processor_id());
+	return ct;
+}
+
 static inline cputime_t jiffies_to_cputime(const unsigned long jif)
 {
 	cputime_t ct;
diff --git a/include/asm-powerpc/paca.h b/include/asm-powerpc/paca.h
index f6dfce0..748b35a 100644
--- a/include/asm-powerpc/paca.h
+++ b/include/asm-powerpc/paca.h
@@ -115,8 +115,6 @@ struct paca_struct {
 	u64 system_time;		/* accumulated system TB ticks */
 	u64 startpurr;			/* PURR/TB value snapshot */
 	u64 startspurr;			/* SPURR value snapshot */
-	u64 purrdelta;			/* FIXME: document */
-	u64 spurrdelta;			/* FIXME: document */
 };
 
 extern struct paca_struct paca[];
diff --git a/include/asm-s390/cputime.h b/include/asm-s390/cputime.h
index 4b3ef7c..133ce05 100644
--- a/include/asm-s390/cputime.h
+++ b/include/asm-s390/cputime.h
@@ -54,6 +54,7 @@ __div(unsigned long long n, unsigned int base)
 #define cputime_lt(__a, __b)		((__a) <  (__b))
 #define cputime_le(__a, __b)		((__a) <= (__b))
 #define cputime_to_jiffies(__ct)	(__div((__ct), 1000000 / HZ))
+#define cputime_to_scaled(__ct)		(__ct)
 #define jiffies_to_cputime(__hz)	((cputime_t)(__hz) * (1000000 / HZ))
 
 #define cputime64_zero			(0ULL)