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authorThomas Gleixner <tglx@linutronix.de>2018-07-12 22:19:58 +0200
committerThomas Gleixner <tglx@linutronix.de>2018-07-12 22:19:58 +0200
commitc6bb11147eb09bd39f316c6062455b88c905ab6e (patch)
tree5a1a6ec2970daef5fa8546741ced3ef3924bf807 /kernel/time/timekeeping.c
parenta8802d97e73346bc81609df9dfba7d3306f40d87 (diff)
parentb061c7a513afe14a68af41cec7c3476befc40e95 (diff)
downloadlinux-c6bb11147eb09bd39f316c6062455b88c905ab6e.tar.bz2
Merge branch 'fortglx/4.19/time' of https://git.linaro.org/people/john.stultz/linux into timers/core
Pull timekeeping updates from John Stultz: - Make the timekeeping update more precise when NTP frequency is set directly by updating the multiplier. - Adjust selftests
Diffstat (limited to 'kernel/time/timekeeping.c')
-rw-r--r--kernel/time/timekeeping.c36
1 files changed, 30 insertions, 6 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 77c436a0070b..ad779c2ec53a 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -34,6 +34,14 @@
#define TK_MIRROR (1 << 1)
#define TK_CLOCK_WAS_SET (1 << 2)
+enum timekeeping_adv_mode {
+ /* Update timekeeper when a tick has passed */
+ TK_ADV_TICK,
+
+ /* Update timekeeper on a direct frequency change */
+ TK_ADV_FREQ
+};
+
/*
* The most important data for readout fits into a single 64 byte
* cache line.
@@ -2021,11 +2029,11 @@ static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
return offset;
}
-/**
- * update_wall_time - Uses the current clocksource to increment the wall time
- *
+/*
+ * timekeeping_advance - Updates the timekeeper to the current time and
+ * current NTP tick length
*/
-void update_wall_time(void)
+static void timekeeping_advance(enum timekeeping_adv_mode mode)
{
struct timekeeper *real_tk = &tk_core.timekeeper;
struct timekeeper *tk = &shadow_timekeeper;
@@ -2042,14 +2050,17 @@ void update_wall_time(void)
#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
offset = real_tk->cycle_interval;
+
+ if (mode != TK_ADV_TICK)
+ goto out;
#else
offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
-#endif
/* Check if there's really nothing to do */
- if (offset < real_tk->cycle_interval)
+ if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK)
goto out;
+#endif
/* Do some additional sanity checking */
timekeeping_check_update(tk, offset);
@@ -2106,6 +2117,15 @@ out:
}
/**
+ * update_wall_time - Uses the current clocksource to increment the wall time
+ *
+ */
+void update_wall_time(void)
+{
+ timekeeping_advance(TK_ADV_TICK);
+}
+
+/**
* getboottime64 - Return the real time of system boot.
* @ts: pointer to the timespec64 to be set
*
@@ -2327,6 +2347,10 @@ int do_adjtimex(struct timex *txc)
write_seqcount_end(&tk_core.seq);
raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+ /* Update the multiplier immediately if frequency was set directly */
+ if (txc->modes & (ADJ_FREQUENCY | ADJ_TICK))
+ timekeeping_advance(TK_ADV_FREQ);
+
if (tai != orig_tai)
clock_was_set();