X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=include%2Flinux%2Ftimes.h;h=0c5aa078dad4a2daf0b3523da9ef1b1b072ad147;hb=c7b5ebbddf7bcd3651947760f423e3783bbe6573;hp=a682537f812e52e1aa806f6c19d41f11414d34ec;hpb=5273a3df6485dc2ad6aa7ddd441b9a21970f003b;p=linux-2.6.git

diff --git a/include/linux/times.h b/include/linux/times.h
index a682537f8..0c5aa078d 100644
--- a/include/linux/times.h
+++ b/include/linux/times.h
@@ -2,15 +2,21 @@
 #define _LINUX_TIMES_H
 
 #ifdef __KERNEL__
+#include <linux/timex.h>
 #include <asm/div64.h>
 #include <asm/types.h>
 #include <asm/param.h>
 
-#if (HZ % USER_HZ)==0
-# define jiffies_to_clock_t(x) ((x) / (HZ / USER_HZ))
+static inline clock_t jiffies_to_clock_t(long x)
+{
+#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
+	return x / (HZ / USER_HZ);
 #else
-# define jiffies_to_clock_t(x) ((clock_t) jiffies_64_to_clock_t((u64) x))
+	u64 tmp = (u64)x * TICK_NSEC;
+	do_div(tmp, (NSEC_PER_SEC / USER_HZ));
+	return (long)tmp;
 #endif
+}
 
 static inline unsigned long clock_t_to_jiffies(unsigned long x)
 {
@@ -34,7 +40,7 @@ static inline unsigned long clock_t_to_jiffies(unsigned long x)
 
 static inline u64 jiffies_64_to_clock_t(u64 x)
 {
-#if (HZ % USER_HZ)==0
+#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
 	do_div(x, HZ / USER_HZ);
 #else
 	/*
@@ -42,13 +48,33 @@ static inline u64 jiffies_64_to_clock_t(u64 x)
 	 * but even this doesn't overflow in hundreds of years
 	 * in 64 bits, so..
 	 */
-	x *= USER_HZ;
-	do_div(x, HZ);
+	x *= TICK_NSEC;
+	do_div(x, (NSEC_PER_SEC / USER_HZ));
 #endif
 	return x;
 }
 #endif
 
+static inline u64 nsec_to_clock_t(u64 x)
+{
+#if (NSEC_PER_SEC % USER_HZ) == 0
+	do_div(x, (NSEC_PER_SEC / USER_HZ));
+#elif (USER_HZ % 512) == 0
+	x *= USER_HZ/512;
+	do_div(x, (NSEC_PER_SEC / 512));
+#else
+	/*
+         * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
+         * overflow after 64.99 years.
+         * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
+         */
+	x *= 9;
+	do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (USER_HZ/2))
+	                          / USER_HZ));
+#endif
+	return x;
+}
+
 struct tms {
 	clock_t tms_utime;
 	clock_t tms_stime;