X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=include%2Flinux%2Facct.h;h=a6ab17c49aa1586310566073c07782aebac1be9d;hb=c7b5ebbddf7bcd3651947760f423e3783bbe6573;hp=b46ce1ac1c6a3e7a96dbde7c8c421e5eceaf68c6;hpb=a2c21200f1c81b08cb55e417b68150bba439b646;p=linux-2.6.git

diff --git a/include/linux/acct.h b/include/linux/acct.h
index b46ce1ac1..a6ab17c49 100644
--- a/include/linux/acct.h
+++ b/include/linux/acct.h
@@ -172,17 +172,24 @@ static inline u32 jiffies_to_AHZ(unsigned long x)
 #endif
 }
 
-static inline u64 jiffies_64_to_AHZ(u64 x)
+static inline u64 nsec_to_AHZ(u64 x)
 {
-#if (TICK_NSEC % (NSEC_PER_SEC / AHZ)) == 0
-#if HZ != AHZ
-	do_div(x, HZ / AHZ);
-#endif
-#else
-	x *= TICK_NSEC;
+#if (NSEC_PER_SEC % AHZ) == 0
 	do_div(x, (NSEC_PER_SEC / AHZ));
+#elif (AHZ % 512) == 0
+	x *= AHZ/512;
+	do_div(x, (NSEC_PER_SEC / 512));
+#else
+	/*
+         * max relative error 5.7e-8 (1.8s per year) for AHZ <= 1024,
+         * overflow after 64.99 years.
+         * exact for AHZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
+         */
+	x *= 9;
+	do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (AHZ/2))
+	                          / AHZ));
 #endif
-       return x;
+	return x;
 }
 
 #endif  /* __KERNEL */