timers/core changes for v3.8

index 6b5cf02..5d1b926 100644
@@ -233,16 +233,15 @@ fs_initcall(init_acpi_pm_clocksource);
  */
 static int __init parse_pmtmr(char *arg)
 {
-	unsigned long base;
+	unsigned int base;
+	int ret;
 
-	if (strict_strtoul(arg, 16, &base))
-		return -EINVAL;
-#ifdef CONFIG_X86_64
-	if (base > UINT_MAX)
-		return -ERANGE;
-#endif
-	printk(KERN_INFO "PMTMR IOPort override: 0x%04x -> 0x%04lx\n",
-	       pmtmr_ioport, base);
+	ret = kstrtouint(arg, 16, &base);
+	if (ret)
+		return ret;
+
+	pr_info("PMTMR IOPort override: 0x%04x -> 0x%04x\n", pmtmr_ioport,
+		base);
 	pmtmr_ioport = base;
 
 	return 1;

index c4d9f95..c210f4f 100644
@@ -127,7 +127,7 @@ static void __init arch_timer_calibrate(void)
 
 	/* Cache the sched_clock multiplier to save a divide in the hot path. */
 
-	sched_clock_mult = NSEC_PER_SEC / arch_timer_rate;
+	sched_clock_mult = DIV_ROUND_CLOSEST(NSEC_PER_SEC, arch_timer_rate);
 
 	pr_info("Architected local timer running at %u.%02uMHz.\n",
 		 arch_timer_rate / 1000000, (arch_timer_rate / 10000) % 100);

@@ -221,10 +221,10 @@ int __init arm_generic_timer_init(void)
 	clocksource_register_hz(&clocksource_counter, arch_timer_rate);
 
 	/* Calibrate the delay loop directly */
-	lpj_fine = arch_timer_rate / HZ;
+	lpj_fine = DIV_ROUND_CLOSEST(arch_timer_rate, HZ);
 
 	/* Immediately configure the timer on the boot CPU */
-	arch_timer_setup(per_cpu_ptr(&arch_timer_evt, smp_processor_id()));
+	arch_timer_setup(this_cpu_ptr(&arch_timer_evt));
 
 	register_cpu_notifier(&arch_timer_cpu_nb);
 

index e7cab2d..14ee3ef 100644
@@ -35,7 +35,7 @@ static cycle_t i8253_read(struct clocksource *cs)
 
 	raw_spin_lock_irqsave(&i8253_lock, flags);
 	/*
-	 * Although our caller may have the read side of xtime_lock,
+	 * Although our caller may have the read side of jiffies_lock,
 	 * this is now a seqlock, and we are cheating in this routine
 	 * by having side effects on state that we cannot undo if
 	 * there is a collision on the seqlock and our caller has to

index 6b87413..82ed068 100644
@@ -70,11 +70,12 @@ extern int register_refined_jiffies(long clock_tick_rate);
 
 /*
  * The 64-bit value is not atomic - you MUST NOT read it
- * without sampling the sequence number in xtime_lock.
+ * without sampling the sequence number in jiffies_lock.
  * get_jiffies_64() will do this for you as appropriate.
  */
 extern u64 __jiffy_data jiffies_64;
 extern unsigned long volatile __jiffy_data jiffies;
+extern seqlock_t jiffies_lock;
 
 #if (BITS_PER_LONG < 64)
 u64 get_jiffies_64(void);

index 6629bf7..7a925ba 100644
@@ -58,7 +58,7 @@ static cycle_t jiffies_read(struct clocksource *cs)
 	return (cycle_t) jiffies;
 }
 
-struct clocksource clocksource_jiffies = {
+static struct clocksource clocksource_jiffies = {
 	.name		= "jiffies",
 	.rating		= 1, /* lowest valid rating*/
 	.read		= jiffies_read,

@@ -67,6 +67,8 @@ struct clocksource clocksource_jiffies = {
 	.shift		= JIFFIES_SHIFT,
 };
 
+__cacheline_aligned_in_smp DEFINE_SEQLOCK(jiffies_lock);
+
 #if (BITS_PER_LONG < 64)
 u64 get_jiffies_64(void)
 {

@@ -74,9 +76,9 @@ u64 get_jiffies_64(void)
 	u64 ret;
 
 	do {
-		seq = read_seqbegin(&xtime_lock);
+		seq = read_seqbegin(&jiffies_lock);
 		ret = jiffies_64;
-	} while (read_seqretry(&xtime_lock, seq));
+	} while (read_seqretry(&jiffies_lock, seq));
 	return ret;
 }
 EXPORT_SYMBOL(get_jiffies_64);

index da6c9ec..b1600a6 100644
@@ -63,13 +63,13 @@ int tick_is_oneshot_available(void)
 static void tick_periodic(int cpu)
 {
 	if (tick_do_timer_cpu == cpu) {
-		write_seqlock(&xtime_lock);
+		write_seqlock(&jiffies_lock);
 
 		/* Keep track of the next tick event */
 		tick_next_period = ktime_add(tick_next_period, tick_period);
 
 		do_timer(1);
-		write_sequnlock(&xtime_lock);
+		write_sequnlock(&jiffies_lock);
 	}
 
 	update_process_times(user_mode(get_irq_regs()));

@@ -130,9 +130,9 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
 		ktime_t next;
 
 		do {
-			seq = read_seqbegin(&xtime_lock);
+			seq = read_seqbegin(&jiffies_lock);
 			next = tick_next_period;
-		} while (read_seqretry(&xtime_lock, seq));
+		} while (read_seqretry(&jiffies_lock, seq));
 
 		clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
 

index 4e265b9..cf3e59e 100644
@@ -141,4 +141,3 @@ static inline int tick_device_is_functional(struct clock_event_device *dev)
 #endif
 
 extern void do_timer(unsigned long ticks);
-extern seqlock_t xtime_lock;

212 lines not on this page · raw message

index e424970..4c7de02 100644
@@ -25,12 +25,6 @@
 
 static struct timekeeper timekeeper;
 
-/*
- * This read-write spinlock protects us from races in SMP while
- * playing with xtime.
- */
-__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
-
 /* flag for if timekeeping is suspended */
 int __read_mostly timekeeping_suspended;
 

@@ -1299,9 +1293,7 @@ struct timespec get_monotonic_coarse(void)
 }
 
 /*
- * The 64-bit jiffies value is not atomic - you MUST NOT read it
- * without sampling the sequence number in xtime_lock.
- * jiffies is defined in the linker script...
+ * Must hold jiffies_lock
  */
 void do_timer(unsigned long ticks)
 {

@@ -1389,7 +1381,7 @@ EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset);
  */
 void xtime_update(unsigned long ticks)
 {
-	write_seqlock(&xtime_lock);
+	write_seqlock(&jiffies_lock);
 	do_timer(ticks);
-	write_sequnlock(&xtime_lock);
+	write_sequnlock(&jiffies_lock);
 }