time: Remove xtime_cache
With the prior logarithmic time accumulation patch, xtime will now
always be within one "tick" of the current time, instead of
possibly half a second off.
This removes the need for the xtime_cache value, which always
stored the time at the last interrupt, so this patch cleans that up
removing the xtime_cache related code.
This is a bit simpler, but still could use some wider testing.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1254525855.7741.95.camel@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/time.c b/kernel/time.c
index 2e2e469..2ef4fe2 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -136,7 +136,6 @@
write_seqlock_irq(&xtime_lock);
wall_to_monotonic.tv_sec -= sys_tz.tz_minuteswest * 60;
xtime.tv_sec += sys_tz.tz_minuteswest * 60;
- update_xtime_cache(0);
write_sequnlock_irq(&xtime_lock);
clock_was_set();
}
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5fdd78e..96b3f0d 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -164,13 +164,6 @@
/* flag for if timekeeping is suspended */
int __read_mostly timekeeping_suspended;
-static struct timespec xtime_cache __attribute__ ((aligned (16)));
-void update_xtime_cache(u64 nsec)
-{
- xtime_cache = xtime;
- timespec_add_ns(&xtime_cache, nsec);
-}
-
/* must hold xtime_lock */
void timekeeping_leap_insert(int leapsecond)
{
@@ -331,8 +324,6 @@
xtime = *tv;
- update_xtime_cache(0);
-
timekeeper.ntp_error = 0;
ntp_clear();
@@ -547,7 +538,6 @@
}
set_normalized_timespec(&wall_to_monotonic,
-boot.tv_sec, -boot.tv_nsec);
- update_xtime_cache(0);
total_sleep_time.tv_sec = 0;
total_sleep_time.tv_nsec = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
@@ -581,7 +571,6 @@
wall_to_monotonic = timespec_sub(wall_to_monotonic, ts);
total_sleep_time = timespec_add_safe(total_sleep_time, ts);
}
- update_xtime_cache(0);
/* re-base the last cycle value */
timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
timekeeper.ntp_error = 0;
@@ -721,7 +710,6 @@
timekeeper.ntp_error_shift;
}
-
/**
* logarithmic_accumulation - shifted accumulation of cycles
*
@@ -765,7 +753,6 @@
return offset;
}
-
/**
* update_wall_time - Uses the current clocksource to increment the wall time
*
@@ -775,7 +762,6 @@
{
struct clocksource *clock;
cycle_t offset;
- u64 nsecs;
int shift = 0, maxshift;
/* Make sure we're fully resumed: */
@@ -841,9 +827,6 @@
timekeeper.ntp_error += timekeeper.xtime_nsec <<
timekeeper.ntp_error_shift;
- nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift);
- update_xtime_cache(nsecs);
-
/* check to see if there is a new clocksource to use */
update_vsyscall(&xtime, timekeeper.clock);
}
@@ -880,13 +863,13 @@
unsigned long get_seconds(void)
{
- return xtime_cache.tv_sec;
+ return xtime.tv_sec;
}
EXPORT_SYMBOL(get_seconds);
struct timespec __current_kernel_time(void)
{
- return xtime_cache;
+ return xtime;
}
struct timespec current_kernel_time(void)
@@ -896,8 +879,7 @@
do {
seq = read_seqbegin(&xtime_lock);
-
- now = xtime_cache;
+ now = xtime;
} while (read_seqretry(&xtime_lock, seq));
return now;
@@ -911,8 +893,7 @@
do {
seq = read_seqbegin(&xtime_lock);
-
- now = xtime_cache;
+ now = xtime;
mono = wall_to_monotonic;
} while (read_seqretry(&xtime_lock, seq));
