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time/jiffies: Rename ACTHZ to SHIFTED_HZ 

Ingo noted that ACTHZ is a confusing name, and requested it
be renamed, so this patch renames ACTHZ to SHIFTED_HZ to
better describe it.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1343414893-45779-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
John Stultz 2012-07-27 14:48:10 -04:00 committed by Ingo Molnar
parent a7ea3bbf5d
commit 02ab20ae38
4 changed files with 16 additions and 11 deletions
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21
include/linux/jiffies.h
View File

@ -55,21 +55,26 @@
/* 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))
/*
* 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 ACTHZ (HZ << 8)
# 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

2
include/linux/timex.h
View File

@ -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);

2
kernel/time/jiffies.c
View File

@ -37,7 +37,7 @@
* requested HZ value. It is also not recommended
* for "tick-less" systems.
*/
#define NSEC_PER_JIFFY ((u32)((((u64)NSEC_PER_SEC)<<8)/ACTHZ))
#define NSEC_PER_JIFFY ((u32)((((u64)NSEC_PER_SEC)<<8)/SHIFTED_HZ))
/* Since jiffies uses a simple NSEC_PER_JIFFY multiplier
* conversion, the .shift value could be zero. However

2
kernel/time/ntp.c
View File

@ -28,7 +28,7 @@ DEFINE_SPINLOCK(ntp_lock);
/* USER_HZ period (usecs): */
unsigned long tick_usec = TICK_USEC;
/* ACTHZ period (nsecs): */
/* SHIFTED_HZ period (nsecs): */
unsigned long tick_nsec;
static u64 tick_length;