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time: Provide get_xtime_and_monotonic_offset()

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The hrtimer code accesses timekeeping variables under
xtime_lock. Provide a sensible accessor function and use it.

[ tglx: Removed the conditionals, unused variable, fixed codingstyle
  	and massaged changelog ]

Signed-off-by: Torben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145905.23248.30458.stgit@localhost>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Torben Hohn 2011-01-27 15:59:05 +01:00 committed by Thomas Gleixner
parent fbad1ea941
commit 48cf76f710
3 changed files with 19 additions and 11 deletions
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1
include/linux/time.h
View file

@ -127,6 +127,7 @@ struct timespec current_kernel_time(void);
struct timespec __current_kernel_time(void); /* does not take xtime_lock */
struct timespec __get_wall_to_monotonic(void); /* does not take xtime_lock */
struct timespec get_monotonic_coarse(void);
void get_xtime_and_monotonic_offset(struct timespec *xtim, struct timespec *wtom);
#define CURRENT_TIME (current_kernel_time())
#define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 })

13
kernel/hrtimer.c
View file

@ -85,13 +85,8 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
{
ktime_t xtim, tomono;
struct timespec xts, tom;
unsigned long seq;
do {
seq = read_seqbegin(&xtime_lock);
xts = __current_kernel_time();
tom = __get_wall_to_monotonic();
} while (read_seqretry(&xtime_lock, seq));
get_xtime_and_monotonic_offset(&xts, &tom);
xtim = timespec_to_ktime(xts);
tomono = timespec_to_ktime(tom);
@ -612,15 +607,11 @@ static void retrigger_next_event(void *arg)
{
struct hrtimer_cpu_base *base;
struct timespec realtime_offset, wtm;
unsigned long seq;
if (!hrtimer_hres_active())
return;
do {
seq = read_seqbegin(&xtime_lock);
wtm = __get_wall_to_monotonic();
} while (read_seqretry(&xtime_lock, seq));
get_xtime_and_monotonic_offset(&realtime_offset, &wtm);
set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
base = &__get_cpu_var(hrtimer_bases);

16
kernel/time/timekeeping.c
View file

@ -958,3 +958,19 @@ void do_timer(unsigned long ticks)
update_wall_time();
calc_global_load(ticks);
}
/**
* get_xtime_and_monotonic_offset() - get xtime and wall_to_monotonic
* @xtim: pointer to timespec to be set with xtime
* @wtom: pointer to timespec to be set with wall_to_monotonic
*/
void get_xtime_and_monotonic_offset(struct timespec *xtim, struct timespec *wtom)
{
unsigned long seq;
do {
seq = read_seqbegin(&xtime_lock);
*xtim = xtime;
*wtom = wall_to_monotonic;
} while (read_seqretry(&xtime_lock, seq));
}