UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

time: Add timekeeping snapshot code capturing system time and counter 

In the current timekeeping code there isn't any interface to
atomically capture the current relationship between the system counter
and system time. ktime_get_snapshot() returns this triple (counter,
monotonic raw, realtime) in the system_time_snapshot struct.

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
[jstultz: Moved structure definitions around to clean things up,
 fixed cycles_t/cycle_t confusion.]
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
Christopher S. Hall 2016-02-22 03:15:20 -08:00 committed by John Stultz
parent 6bd58f09e1
commit 9da0f49c87
2 changed files with 48 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
include/linux/timekeeping.h
View File

@ -266,6 +266,24 @@ extern void timekeeping_inject_sleeptime64(struct timespec64 *delta);
extern void ktime_get_raw_and_real_ts64(struct timespec64 *ts_raw,
struct timespec64 *ts_real);
/*
* struct system_time_snapshot - simultaneous raw/real time capture with
* counter value
* @cycles: Clocksource counter value to produce the system times
* @real: Realtime system time
* @raw: Monotonic raw system time
*/
struct system_time_snapshot {
cycle_t cycles;
ktime_t real;
ktime_t raw;
};
/*
* Simultaneously snapshot realtime and monotonic raw clocks
*/
extern void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot);
/*
* Persistent clock related interfaces
*/

30
kernel/time/timekeeping.c
View File

@ -874,6 +874,36 @@ time64_t __ktime_get_real_seconds(void)
return tk->xtime_sec;
}
/**
* ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
* @systime_snapshot: pointer to struct receiving the system time snapshot
*/
void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
{
struct timekeeper *tk = &tk_core.timekeeper;
unsigned long seq;
ktime_t base_raw;
ktime_t base_real;
s64 nsec_raw;
s64 nsec_real;
cycle_t now;
do {
seq = read_seqcount_begin(&tk_core.seq);
now = tk->tkr_mono.read(tk->tkr_mono.clock);
base_real = ktime_add(tk->tkr_mono.base,
tk_core.timekeeper.offs_real);
base_raw = tk->tkr_raw.base;
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));
systime_snapshot->cycles = now;
systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
}
EXPORT_SYMBOL_GPL(ktime_get_snapshot);
#ifdef CONFIG_NTP_PPS