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-rw-r--r--kernel/time/sched_clock.c26
1 files changed, 11 insertions, 15 deletions
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index ca3bc5c7027c..1751e956add9 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -58,23 +58,21 @@ static inline u64 notrace cyc_to_ns(u64 cyc, u32 mult, u32 shift)
unsigned long long notrace sched_clock(void)
{
- u64 epoch_ns;
- u64 epoch_cyc;
- u64 cyc;
+ u64 cyc, res;
unsigned long seq;
- if (cd.suspended)
- return cd.epoch_ns;
-
do {
seq = raw_read_seqcount_begin(&cd.seq);
- epoch_cyc = cd.epoch_cyc;
- epoch_ns = cd.epoch_ns;
+
+ res = cd.epoch_ns;
+ if (!cd.suspended) {
+ cyc = read_sched_clock();
+ cyc = (cyc - cd.epoch_cyc) & sched_clock_mask;
+ res += cyc_to_ns(cyc, cd.mult, cd.shift);
+ }
} while (read_seqcount_retry(&cd.seq, seq));
- cyc = read_sched_clock();
- cyc = (cyc - epoch_cyc) & sched_clock_mask;
- return epoch_ns + cyc_to_ns(cyc, cd.mult, cd.shift);
+ return res;
}
/*
@@ -111,7 +109,6 @@ void __init sched_clock_register(u64 (*read)(void), int bits,
{
u64 res, wrap, new_mask, new_epoch, cyc, ns;
u32 new_mult, new_shift;
- ktime_t new_wrap_kt;
unsigned long r;
char r_unit;
@@ -124,10 +121,11 @@ void __init sched_clock_register(u64 (*read)(void), int bits,
clocks_calc_mult_shift(&new_mult, &new_shift, rate, NSEC_PER_SEC, 3600);
new_mask = CLOCKSOURCE_MASK(bits);
+ cd.rate = rate;
/* calculate how many nanosecs until we risk wrapping */
wrap = clocks_calc_max_nsecs(new_mult, new_shift, 0, new_mask, NULL);
- new_wrap_kt = ns_to_ktime(wrap);
+ cd.wrap_kt = ns_to_ktime(wrap);
/* update epoch for new counter and update epoch_ns from old counter*/
new_epoch = read();
@@ -138,8 +136,6 @@ void __init sched_clock_register(u64 (*read)(void), int bits,
raw_write_seqcount_begin(&cd.seq);
read_sched_clock = read;
sched_clock_mask = new_mask;
- cd.rate = rate;
- cd.wrap_kt = new_wrap_kt;
cd.mult = new_mult;
cd.shift = new_shift;
cd.epoch_cyc = new_epoch;