[PATCH v4 02/10] timekeeper: introduce boot field in system_time_snapshot

Denis Plotnikov
2017-08-02T14:39:32Z

The field keeps monotonic time since boot.

The value of boot will be used in KVM for masterclock.

This is a part of the work aiming to move to a more simple scheme
of masterclock related values calculation in KVM

Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
---
include/linux/timekeeping.h | 2 ++
kernel/time/timekeeping.c | 4 ++++
2 files changed, 6 insertions(+)

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index ddc229f..5008e3e 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -283,6 +283,7 @@ extern void ktime_get_raw_and_real_ts64(struct timespec64 *ts_raw,
* @cycles: Clocksource counter value to produce the system times
* @real: Realtime system time
* @raw: Monotonic raw system time
+ * @boot: Monotonic time since boot
* @clock_was_set_seq: The sequence number of clock was set events
* @cs_was_changed_seq: The sequence number of clocksource change events
*/
@@ -290,6 +291,7 @@ struct system_time_snapshot {
u64 cycles;
ktime_t real;
ktime_t raw;
+ ktime_t boot;
unsigned int clock_was_set_seq;
u8 cs_was_changed_seq;
};
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index cedafa0..66f7701 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -953,6 +953,7 @@ void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
unsigned long seq;
ktime_t base_raw;
ktime_t base_real;
+ ktime_t base_boot;
u64 nsec_raw;
u64 nsec_real;
u64 now;
@@ -967,6 +968,8 @@ void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
base_real = ktime_add(tk->tkr_mono.base,
tk_core.timekeeper.offs_real);
base_raw = tk->tkr_raw.base;
+ base_boot = ktime_add(tk->tkr_mono.base,
+ tk_core.timekeeper.offs_boot);
nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
} while (read_seqcount_retry(&tk_core.seq, seq));
@@ -974,6 +977,7 @@ void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
systime_snapshot->cycles = now;
systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
+ systime_snapshot->boot = ktime_add_ns(base_boot, nsec_real);
}
EXPORT_SYMBOL_GPL(ktime_get_snapshot);

--
2.7.4