[RFC][PATCH - 5/12] NTP cleanup: Break out leapsecond processing
All,
This patch breaks the leapsecond processing logic into its own
function. By making the NTP code avoid making any direct changes to
time, instead allowing the time code to use NTP to decide when to change
time, we better isolate the NTP subsystem.
Any comments or feedback would be greatly appreciated.
thanks
-john
linux-2.6.13-rc3_timeofday-ntp-part5_B4.patch
diff --git a/include/linux/ntp.h b/include/linux/ntp.h
--- a/include/linux/ntp.h
+++ b/include/linux/ntp.h
@@ -13,6 +13,7 @@
int ntp_advance(void);
int ntp_adjtimex(struct timex*);
void second_overflow(void);
+int ntp_leapsecond(struct timespec now);
void ntp_clear(void);
int ntp_synced(void);
diff --git a/kernel/ntp.c b/kernel/ntp.c
--- a/kernel/ntp.c
+++ b/kernel/ntp.c
@@ -40,12 +40,6 @@
#include
#include
-#ifdef CONFIG_TIME_INTERPOLATION
-void time_interpolator_update(long delta_nsec);
-#else
-#define time_interpolator_update(x)
-#endif
-
/* Don't completely fail for HZ > 500. */
int tickadj = 500/HZ ? : 1;/* microsecs */
@@ -69,6 +63,8 @@ static long time_reftime;
long time_adjust;
static long time_next_adjust;
+#define SEC_PER_DAY 86400
+
/* Required to safely shift negative values */
#define shiftR(x,s) (x < 0) ? (-((-x) >> (s))) : ((x) >> (s))
@@ -142,59 +138,6 @@ void second_overflow(void)
}
/*
-* Leap second processing. If in leap-insert state at
-* the end of the day, the system clock is set back one
-* second; if in leap-delete state, the system clock is
-* set ahead one second. The microtime() routine or
-* external clock driver will insure that reported time
-* is always monotonic. The ugly divides should be
-* replaced.
-*/
- switch (time_state) {
-
- case TIME_OK:
- if (time_status & STA_INS)
- time_state = TIME_INS;
- else if (time_status & STA_DEL)
- time_state = TIME_DEL;
- break;
-
- case TIME_INS:
- if (xtime.tv_sec % 86400 == 0) {
- xtime.tv_sec--;
- wall_to_monotonic.tv_sec++;
- /* The timer interpolator will make time change
gradually instead
-* of an immediate jump by one second.
-*/
- time_interpolator_update(-NSEC_PER_SEC);
- time_state = TIME_OOP;
- clock_was_set();
- printk(KERN_NOTICE "Clock: inserting leap second
23:59:60 UTC\n");
- }
- break;
-
- case TIME_DEL:
- if ((xtime.tv_sec + 1) % 86400 == 0) {
- xtime.tv_sec++;
- wall_to_monotonic.tv_sec--;
- /* Use of time interpolator for a gradual change of
time */
- time_interpolator_update(NSEC_PER_SEC);
- time_state = TIME_WAIT;
- clock_was_set();
- printk(KERN_NOTICE "Clock: deleting leap second
23:59:59 UTC\n");
- }
- break;
-
- case TIME_OOP:
- time_state = TIME_WAIT;
- break;
-
- case TIME_WAIT:
- if (!(time_status & (STA_INS | STA_DEL)))
- time_state = TIME_OK;
- }
-
- /*
* Compute the phase adjustment for the next second. In
* PLL mode, the offset is reduced by a fixed factor
* times the time constant. In FLL mode the offset is
@@ -438,6 +381,70 @@ leave:
return result;
}
+
+/**
+ * ntp_leapsecond - NTP leapsecond processing code.
+ * now: the current time
+ *
+ * Returns the number of seconds (-1, 0, or 1) that
+ * should be added to the current time to properly
+ * adjust for leapseconds.
+ */
+int ntp_leapsecond(struct timespec now)
+{
+ /*
+* Leap second processing. If in leap-insert state at
+* the end of the day, the system clock is set back one
+* second; if in leap-delete state, the system clock is
+* set ahead one second.
+*/
+ static time_t leaptime = 0;
+
+ switch (time_state) {
+ case TIME_OK:
+ if (time_status & STA_INS)
+ time_state = TIME_INS;
+ else if (time_status & STA_DEL)
+ time_state = TIME_DEL;
+
+ /* calculate end of today (23:59:59)*/
+ leaptime = now.tv_sec + SEC_PER_DAY -
+ (now.tv_sec % SEC_PER_DAY) - 1;
+ break;
+
+ case TIME_INS:
+ /* Once we are at (or past) leaptime, insert the second */
+ if (now.tv_sec >= leaptime) {
+ time_state = TIME_OOP;
+ printk(KERN_NOTICE "Clock: inserting leap
[RFC][PATCH - 5/12] NTP cleanup: Break out leapsecond processing
All,
This patch breaks the leapsecond processing logic into its own
function. By making the NTP code avoid making any direct changes to
time, instead allowing the time code to use NTP to decide when to change
time, we better isolate the NTP subsystem.
Any comments or feedback would be greatly appreciated.
thanks
-john
linux-2.6.13-rc3_timeofday-ntp-part5_B4.patch
diff --git a/include/linux/ntp.h b/include/linux/ntp.h
--- a/include/linux/ntp.h
+++ b/include/linux/ntp.h
@@ -13,6 +13,7 @@
int ntp_advance(void);
int ntp_adjtimex(struct timex*);
void second_overflow(void);
+int ntp_leapsecond(struct timespec now);
void ntp_clear(void);
int ntp_synced(void);
diff --git a/kernel/ntp.c b/kernel/ntp.c
--- a/kernel/ntp.c
+++ b/kernel/ntp.c
@@ -40,12 +40,6 @@
#include linux/jiffies.h
#include linux/errno.h
-#ifdef CONFIG_TIME_INTERPOLATION
-void time_interpolator_update(long delta_nsec);
-#else
-#define time_interpolator_update(x)
-#endif
-
/* Don't completely fail for HZ 500. */
int tickadj = 500/HZ ? : 1;/* microsecs */
@@ -69,6 +63,8 @@ static long time_reftime;
long time_adjust;
static long time_next_adjust;
+#define SEC_PER_DAY 86400
+
/* Required to safely shift negative values */
#define shiftR(x,s) (x 0) ? (-((-x) (s))) : ((x) (s))
@@ -142,59 +138,6 @@ void second_overflow(void)
}
/*
-* Leap second processing. If in leap-insert state at
-* the end of the day, the system clock is set back one
-* second; if in leap-delete state, the system clock is
-* set ahead one second. The microtime() routine or
-* external clock driver will insure that reported time
-* is always monotonic. The ugly divides should be
-* replaced.
-*/
- switch (time_state) {
-
- case TIME_OK:
- if (time_status STA_INS)
- time_state = TIME_INS;
- else if (time_status STA_DEL)
- time_state = TIME_DEL;
- break;
-
- case TIME_INS:
- if (xtime.tv_sec % 86400 == 0) {
- xtime.tv_sec--;
- wall_to_monotonic.tv_sec++;
- /* The timer interpolator will make time change
gradually instead
-* of an immediate jump by one second.
-*/
- time_interpolator_update(-NSEC_PER_SEC);
- time_state = TIME_OOP;
- clock_was_set();
- printk(KERN_NOTICE Clock: inserting leap second
23:59:60 UTC\n);
- }
- break;
-
- case TIME_DEL:
- if ((xtime.tv_sec + 1) % 86400 == 0) {
- xtime.tv_sec++;
- wall_to_monotonic.tv_sec--;
- /* Use of time interpolator for a gradual change of
time */
- time_interpolator_update(NSEC_PER_SEC);
- time_state = TIME_WAIT;
- clock_was_set();
- printk(KERN_NOTICE Clock: deleting leap second
23:59:59 UTC\n);
- }
- break;
-
- case TIME_OOP:
- time_state = TIME_WAIT;
- break;
-
- case TIME_WAIT:
- if (!(time_status (STA_INS | STA_DEL)))
- time_state = TIME_OK;
- }
-
- /*
* Compute the phase adjustment for the next second. In
* PLL mode, the offset is reduced by a fixed factor
* times the time constant. In FLL mode the offset is
@@ -438,6 +381,70 @@ leave:
return result;
}
+
+/**
+ * ntp_leapsecond - NTP leapsecond processing code.
+ * now: the current time
+ *
+ * Returns the number of seconds (-1, 0, or 1) that
+ * should be added to the current time to properly
+ * adjust for leapseconds.
+ */
+int ntp_leapsecond(struct timespec now)
+{
+ /*
+* Leap second processing. If in leap-insert state at
+* the end of the day, the system clock is set back one
+* second; if in leap-delete state, the system clock is
+* set ahead one second.
+*/
+ static time_t leaptime = 0;
+
+ switch (time_state) {
+ case TIME_OK:
+ if (time_status STA_INS)
+ time_state = TIME_INS;
+ else if (time_status STA_DEL)
+ time_state = TIME_DEL;
+
+ /* calculate end of today (23:59:59)*/
+ leaptime = now.tv_sec + SEC_PER_DAY -
+ (now.tv_sec % SEC_PER_DAY) - 1;
+ break;
+
+ case TIME_INS:
+ /* Once we are at (or past) leaptime, insert the second */
+ if (now.tv_sec = leaptime) {
+ time_state = TIME_OOP;
+ printk(KERN_NOTICE Clock:
