Fix POSIX timers to give CLOCK_MONOTONIC full resolution and tie it to xtime instead of jiffies

diff -urP -I '\$Id:.*Exp \$' -X /usr/src/patch.exclude linux-2.5.67-bk3-fix/arch/i386/kernel/time.c linux/arch/i386/kernel/time.c
@@ -121,15 +121,28 @@
 	 * made, and then undo it!
 	 */
 	tv->tv_usec -= timer->get_offset();
-	tv->tv_usec -= (jiffies - wall_jiffies) * (1000000 / HZ);
+	tv->tv_usec -= (jiffies - wall_jiffies) * (USEC_PER_SEC / HZ);
 
 	while (tv->tv_usec < 0) {
-		tv->tv_usec += 1000000;
+		tv->tv_usec += USEC_PER_SEC;
 		tv->tv_sec--;
 	}
+	tv->tv_usec *= NSEC_PER_USEC;
+
+	wall_to_monotonic.tv_sec += xtime.tv_sec - tv->tv_sec;
+	wall_to_monotonic.tv_nsec += xtime.tv_nsec - tv->tv_usec;
+
+	if(wall_to_monotonic.tv_nsec > NSEC_PER_SEC){
+		wall_to_monotonic.tv_nsec -= NSEC_PER_SEC;
+		wall_to_monotonic.tv_sec++;
+	}
+	if(wall_to_monotonic.tv_nsec < 0){
+		wall_to_monotonic.tv_nsec += NSEC_PER_SEC;
+		wall_to_monotonic.tv_sec--;
+	}
 
 	xtime.tv_sec = tv->tv_sec;
-	xtime.tv_nsec = (tv->tv_usec * 1000);
+	xtime.tv_nsec = tv->tv_usec;
 	time_adjust = 0;		/* stop active adjtime() */
 	time_status |= STA_UNSYNC;
 	time_maxerror = NTP_PHASE_LIMIT;

@@ -401,7 +414,9 @@
 {
 	
 	xtime.tv_sec = get_cmos_time();
-	xtime.tv_nsec = 0;
+	wall_to_monotonic.tv_sec = -xtime.tv_sec + INITIAL_JIFFIES / HZ;
+	xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
+	wall_to_monotonic.tv_nsec = 0;
 
 
 	timer = select_timer();

diff -urP -I '\$Id:.*Exp \$' -X /usr/src/patch.exclude linux-2.5.67-bk3-fix/include/linux/time.h linux/include/linux/time.h
@@ -140,6 +140,7 @@
 }
 
 extern struct timespec xtime;
+extern struct timespec wall_to_monotonic;
 extern seqlock_t xtime_lock;
 
 static inline unsigned long get_seconds(void)

@@ -200,6 +201,9 @@
 #define CLOCK_MONOTONIC_HR	  5
 
 #define MAX_CLOCKS 6
+#define CLOCKS_MASK  (CLOCK_REALTIME | CLOCK_MONOTONIC | \
+                     CLOCK_REALTIME_HR | CLOCK_MONOTONIC_HR)
+#define CLOCKS_MONO (CLOCK_MONOTONIC & CLOCK_MONOTONIC_HR)
 
 /*
  * The various flags for setting POSIX.1b interval timers.

316 lines not on this page · raw message

diff -urP -I '\$Id:.*Exp \$' -X /usr/src/patch.exclude linux-2.5.67-bk3-fix/kernel/timer.c linux/kernel/timer.c
@@ -440,8 +440,16 @@
 unsigned long tick_usec = TICK_USEC; 		/* ACTHZ   period (usec) */
 unsigned long tick_nsec = TICK_NSEC(TICK_USEC);	/* USER_HZ period (nsec) */
 
-/* The current time */
+/* 
+ * The current time 
+ * wall_to_monotonic is what we need to add to xtime (or xtime corrected 
+ * for sub jiffie times) to get to monotonic time.  Monotonic is pegged at zero
+ * at zero at system boot time, so wall_to_monotonic will be negative,
+ * however, we will ALWAYS keep the tv_nsec part positive so we can use
+ * the usual normalization.
+ */
 struct timespec xtime __attribute__ ((aligned (16)));
+struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
 
 /* Don't completely fail for HZ > 500.  */
 int tickadj = 500/HZ ? : 1;		/* microsecs */

@@ -507,6 +515,7 @@
     case TIME_INS:
 	if (xtime.tv_sec % 86400 == 0) {
 	    xtime.tv_sec--;
+	    wall_to_monotonic.tv_sec++;
 	    time_state = TIME_OOP;
 	    clock_was_set();
 	    printk(KERN_NOTICE "Clock: inserting leap second 23:59:60 UTC\n");

@@ -516,6 +525,7 @@
     case TIME_DEL:
 	if ((xtime.tv_sec + 1) % 86400 == 0) {
 	    xtime.tv_sec++;
+	    wall_to_monotonic.tv_sec--;
 	    time_state = TIME_WAIT;
 	    clock_was_set();
 	    printk(KERN_NOTICE "Clock: deleting leap second 23:59:59 UTC\n");