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-rw-r--r--kernel/acct.c2
-rw-r--r--kernel/hrtimer.c6
-rw-r--r--kernel/time.c16
-rw-r--r--kernel/time/timekeeping.c38
-rw-r--r--kernel/tsacct.c2
5 files changed, 40 insertions, 24 deletions
diff --git a/kernel/acct.c b/kernel/acct.c
index 70d0d88e555..24f0f8b2ba7 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -468,7 +468,7 @@ static void do_acct_process(struct file *file)
}
#endif
do_div(elapsed, AHZ);
- ac.ac_btime = xtime.tv_sec - elapsed;
+ ac.ac_btime = get_seconds() - elapsed;
/* we really need to bite the bullet and change layout */
ac.ac_uid = current->uid;
ac.ac_gid = current->gid;
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index eb1ddebd2c0..c21ca6bfaa6 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -141,11 +141,7 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
do {
seq = read_seqbegin(&xtime_lock);
-#ifdef CONFIG_NO_HZ
- getnstimeofday(&xts);
-#else
- xts = xtime;
-#endif
+ xts = current_kernel_time();
tom = wall_to_monotonic;
} while (read_seqretry(&xtime_lock, seq));
diff --git a/kernel/time.c b/kernel/time.c
index 5b81da08bbd..2289a8d6831 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -215,22 +215,6 @@ asmlinkage long sys_adjtimex(struct timex __user *txc_p)
return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
}
-inline struct timespec current_kernel_time(void)
-{
- struct timespec now;
- unsigned long seq;
-
- do {
- seq = read_seqbegin(&xtime_lock);
-
- now = xtime;
- } while (read_seqretry(&xtime_lock, seq));
-
- return now;
-}
-
-EXPORT_SYMBOL(current_kernel_time);
-
/**
* current_fs_time - Return FS time
* @sb: Superblock.
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 88c81026e00..acc417b5a9b 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -47,10 +47,22 @@ EXPORT_SYMBOL(xtime_lock);
struct timespec xtime __attribute__ ((aligned (16)));
struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
static unsigned long total_sleep_time; /* seconds */
-
EXPORT_SYMBOL(xtime);
+#ifdef CONFIG_NO_HZ
+static struct timespec xtime_cache __attribute__ ((aligned (16)));
+static inline void update_xtime_cache(u64 nsec)
+{
+ xtime_cache = xtime;
+ timespec_add_ns(&xtime_cache, nsec);
+}
+#else
+#define xtime_cache xtime
+/* We do *not* want to evaluate the argument for this case */
+#define update_xtime_cache(n) do { } while (0)
+#endif
+
static struct clocksource *clock; /* pointer to current clocksource */
@@ -478,6 +490,8 @@ void update_wall_time(void)
xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
+ update_xtime_cache(cyc2ns(clock, offset));
+
/* check to see if there is a new clocksource to use */
change_clocksource();
update_vsyscall(&xtime, clock);
@@ -509,3 +523,25 @@ void monotonic_to_bootbased(struct timespec *ts)
{
ts->tv_sec += total_sleep_time;
}
+
+unsigned long get_seconds(void)
+{
+ return xtime_cache.tv_sec;
+}
+EXPORT_SYMBOL(get_seconds);
+
+
+struct timespec current_kernel_time(void)
+{
+ struct timespec now;
+ unsigned long seq;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+
+ now = xtime_cache;
+ } while (read_seqretry(&xtime_lock, seq));
+
+ return now;
+}
+EXPORT_SYMBOL(current_kernel_time);
diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 658f638c402..c122131a122 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -39,7 +39,7 @@ void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
ac_etime = timespec_to_ns(&ts);
do_div(ac_etime, NSEC_PER_USEC);
stats->ac_etime = ac_etime;
- stats->ac_btime = xtime.tv_sec - ts.tv_sec;
+ stats->ac_btime = get_seconds() - ts.tv_sec;
if (thread_group_leader(tsk)) {
stats->ac_exitcode = tsk->exit_code;
if (tsk->flags & PF_FORKNOEXEC)