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authorLinus Torvalds <torvalds@linux-foundation.org>2012-08-03 10:58:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-08-03 10:58:57 -0700
commitddc5057c1c1fb3e99afeeef45d2b8ff9597e6707 (patch)
tree801e4842f3a4dce2d777336b54f3caf075975025 /include
parentfcc1d2a9cea4ba97c9800e1de0748003bba07335 (diff)
parent4e250fdde9be50581c7dd5fed88c9b9960615314 (diff)
downloadlinux-ddc5057c1c1fb3e99afeeef45d2b8ff9597e6707.tar.bz2
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Ingo Molnar: "One regression fix, and a couple of cleanups that clean up the code flow in areas that had high-profile bugs recently." * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: time: Remove all direct references to timekeeper time: Clean up offs_real/wall_to_mono and offs_boot/total_sleep_time updates time: Clean up stray newlines time/jiffies: Rename ACTHZ to SHIFTED_HZ time/jiffies: Allow CLOCK_TICK_RATE to be undefined time: Fix casting issue in tk_set_xtime and tk_xtime_add
Diffstat (limited to 'include')
-rw-r--r--include/linux/jiffies.h29
-rw-r--r--include/linux/timex.h2
2 files changed, 20 insertions, 11 deletions
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 265e2c3cbd1c..82680541576d 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -39,9 +39,6 @@
# error Invalid value of HZ.
#endif
-/* LATCH is used in the interval timer and ftape setup. */
-#define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */
-
/* Suppose we want to divide two numbers NOM and DEN: NOM/DEN, then we can
* improve accuracy by shifting LSH bits, hence calculating:
* (NOM << LSH) / DEN
@@ -54,18 +51,30 @@
#define SH_DIV(NOM,DEN,LSH) ( (((NOM) / (DEN)) << (LSH)) \
+ ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) / (DEN))
-/* HZ is the requested value. ACTHZ is actual HZ ("<< 8" is for accuracy) */
-#define ACTHZ (SH_DIV (CLOCK_TICK_RATE, LATCH, 8))
+#ifdef CLOCK_TICK_RATE
+/* LATCH is used in the interval timer and ftape setup. */
+# define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */
+
+/*
+ * HZ is the requested value. However the CLOCK_TICK_RATE may not allow
+ * for exactly HZ. So SHIFTED_HZ is high res HZ ("<< 8" is for accuracy)
+ */
+# define SHIFTED_HZ (SH_DIV(CLOCK_TICK_RATE, LATCH, 8))
+#else
+# define SHIFTED_HZ (HZ << 8)
+#endif
-/* TICK_NSEC is the time between ticks in nsec assuming real ACTHZ */
-#define TICK_NSEC (SH_DIV (1000000UL * 1000, ACTHZ, 8))
+/* TICK_NSEC is the time between ticks in nsec assuming SHIFTED_HZ */
+#define TICK_NSEC (SH_DIV(1000000UL * 1000, SHIFTED_HZ, 8))
/* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */
#define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ)
-/* TICK_USEC_TO_NSEC is the time between ticks in nsec assuming real ACTHZ and */
-/* a value TUSEC for TICK_USEC (can be set bij adjtimex) */
-#define TICK_USEC_TO_NSEC(TUSEC) (SH_DIV (TUSEC * USER_HZ * 1000, ACTHZ, 8))
+/*
+ * TICK_USEC_TO_NSEC is the time between ticks in nsec assuming SHIFTED_HZ and
+ * a value TUSEC for TICK_USEC (can be set bij adjtimex)
+ */
+#define TICK_USEC_TO_NSEC(TUSEC) (SH_DIV(TUSEC * USER_HZ * 1000, SHIFTED_HZ, 8))
/* some arch's have a small-data section that can be accessed register-relative
* but that can only take up to, say, 4-byte variables. jiffies being part of
diff --git a/include/linux/timex.h b/include/linux/timex.h
index 99bc88b1fc02..7c5ceb20e03a 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -232,7 +232,7 @@ struct timex {
* estimated error = NTP dispersion.
*/
extern unsigned long tick_usec; /* USER_HZ period (usec) */
-extern unsigned long tick_nsec; /* ACTHZ period (nsec) */
+extern unsigned long tick_nsec; /* SHIFTED_HZ period (nsec) */
extern void ntp_init(void);
extern void ntp_clear(void);