On 07/19/2012 02:37 AM, Ingo Molnar wrote:
* John Stultz <john.stu...@linaro.org> wrote:
From: Catalin Marinas <catalin.mari...@arm.com>
...
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 265e2c3..a2134be 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
@@ -54,8 +51,15 @@
#define SH_DIV(NOM,DEN,LSH) ( (((NOM) / (DEN)) << (LSH)) \
+ ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) /
(DEN))
+#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. ACTHZ is actual HZ ("<< 8" is for accuracy) */
#define ACTHZ (SH_DIV (CLOCK_TICK_RATE, LATCH, 8))
+#else
+#define ACTHZ (HZ << 8)
+#endif
The ACTHZ naming ugliness slipped past me. 'ACT' can mean so
many things - please improve it to something more obvious, like
'REAL_HZ' or 'KERNEL_HZ'.
ACTHZ has been around for a while. ~2002 I think?
Is it ok if I do the rename in a following patch?
Also, we tend to write such #if/#else/#endif patterns as:
#if FOO
# define BAR
#else
# define BAZ
#endif
I'll fix this.
Thanks for the review
-john
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