clocksource update v12

Index: linux-2.6.19/kernel/time/clocksource.c
===================================================================
@@ -28,7 +28,6 @@
 #include <linux/sysdev.h>
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/tick.h>
 
 /* XXX - Would like a better way for initializing curr_clocksource */
 extern struct clocksource clocksource_jiffies;

@@ -107,16 +106,8 @@ static void clocksource_watchdog(unsigne
 		/* Initialized ? */
 		if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
 			if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
-			    (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) {
+			    (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS))
 				cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
-				/*
-				 * We just marked the clocksource as
-				 * highres-capable, notify the rest of the
-				 * system as well so that we transition
-				 * into high-res mode:
-				 */
-				tick_clock_notify();
-			}
 			cs->flags |= CLOCK_SOURCE_WATCHDOG;
 			cs->wd_last = csnow;
 		} else {

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Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -12,13 +12,11 @@
 #include <linux/timex.h>
 #include <linux/time.h>
 #include <linux/list.h>
-#include <linux/timer.h>
 #include <asm/div64.h>
 #include <asm/io.h>
 
 /* clocksource cycle base type */
 typedef u64 cycle_t;
-struct clocksource;
 
 /**
  * struct clocksource - hardware abstraction for a free running counter

@@ -66,22 +64,13 @@ struct clocksource {
 	cycle_t cycle_last, cycle_interval;
 	u64 xtime_nsec, xtime_interval;
 	s64 error;
-
-#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
-	/* Watchdog related data, used by the framework */
-	struct list_head wd_list;
-	cycle_t wd_last;
-#endif
 };
 
 /*
  * Clock source flags bits::
  */
-#define CLOCK_SOURCE_IS_CONTINUOUS		0x01
-#define CLOCK_SOURCE_MUST_VERIFY		0x02
-
-#define CLOCK_SOURCE_WATCHDOG			0x10
-#define CLOCK_SOURCE_VALID_FOR_HRES		0x20
+#define CLOCK_SOURCE_IS_CONTINUOUS	0x01
+#define CLOCK_SOURCE_MUST_VERIFY	0x02
 
 /* simplify initialization of mask field */
 #define CLOCKSOURCE_MASK(bits) (cycle_t)(bits<64 ? ((1ULL<<bits)-1) : -1)

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Index: linux-2.6.19/arch/i386/kernel/tsc.c
===================================================================
@@ -60,6 +60,12 @@ static inline int check_tsc_unstable(voi
 	return tsc_unstable;
 }
 
+void mark_tsc_unstable(void)
+{
+	tsc_unstable = 1;
+}
+EXPORT_SYMBOL_GPL(mark_tsc_unstable);
+
 /* Accellerators for sched_clock()
  * convert from cycles(64bits) => nanoseconds (64bits)
  *  basic equation:

@@ -289,6 +295,7 @@ core_initcall(cpufreq_tsc);
 /* clock source code */
 
 static unsigned long current_tsc_khz = 0;
+static int tsc_update_callback(void);
 
 static cycle_t read_tsc(void)
 {

@@ -306,28 +313,38 @@ static struct clocksource clocksource_ts
 	.mask			= CLOCKSOURCE_MASK(64),
 	.mult			= 0, /* to be set */
 	.shift			= 22,
+	.update_callback	= tsc_update_callback,
 	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |
 				  CLOCK_SOURCE_MUST_VERIFY,
 };
 
-void mark_tsc_unstable(void)
+static int tsc_update_callback(void)
 {
-	if (!tsc_unstable) {
-		tsc_unstable = 1;
-		/* Can be called before registration */
-		if (clocksource_tsc.mult)
-			clocksource_change_rating(&clocksource_tsc, 0);
-		else
-			clocksource_tsc.rating = 0;
+	int change = 0;
+
+	/* check to see if we should switch to the safe clocksource: */
+	if (clocksource_tsc.rating != 0 && check_tsc_unstable()) {
+		clocksource_tsc.rating = 0;
+		clocksource_reselect();
+		change = 1;
+	}
+
+	/* only update if tsc_khz has changed: */
+	if (current_tsc_khz != tsc_khz) {
+		current_tsc_khz = tsc_khz;
+		clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
+							clocksource_tsc.shift);
+		change = 1;
 	}
+
+	return change;
 }
-EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
 static int __init dmi_mark_tsc_unstable(struct dmi_system_id *d)
 {
 	printk(KERN_NOTICE "%s detected: marking TSC unstable.\n",
 		       d->ident);
-	tsc_unstable = 1;
+	mark_tsc_unstable();
 	return 0;
 }
 

@@ -399,12 +416,11 @@ __cpuinit int unsynchronized_tsc(void)
 	 * Intel systems are normally all synchronized.
 	 * Exceptions must mark TSC as unstable:
 	 */
-	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) {
-		/* assume multi socket systems are not synchronized: */
-		if (num_possible_cpus() > 1)
-			tsc_unstable = 1;
-	}
-	return tsc_unstable;
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
+ 		return 0;
+
+	/* assume multi socket systems are not synchronized: */
+ 	return num_possible_cpus() > 1;
 }
 
 /*

@@ -433,7 +449,8 @@ static int __init init_tsc_clocksource(v
 		/* check blacklist */
 		dmi_check_system(bad_tsc_dmi_table);
 
-		unsynchronized_tsc();
+		if (unsynchronized_tsc()) /* mark unstable if unsynced */
+			mark_tsc_unstable();
 		check_geode_tsc_reliable();
 		current_tsc_khz = tsc_khz;
 		clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -44,6 +44,7 @@ typedef u64 cycle_t;
  *			subtraction of non 64 bit counters
  * @mult:		cycle to nanosecond multiplier
  * @shift:		cycle to nanosecond divisor (power of two)
+ * @update_callback:	called when safe to alter clocksource values
  * @flags:		flags describing special properties
  * @vread:		vsyscall based read
  * @cycle_interval:	Used internally by timekeeping core, please ignore.

@@ -57,6 +58,7 @@ struct clocksource {
 	cycle_t mask;
 	u32 mult;
 	u32 shift;
+	int (*update_callback)(void);
 	unsigned long flags;
 	cycle_t (*vread)(void);
 

@@ -184,9 +186,9 @@ static inline void clocksource_calculate
 
 
 /* used to install a new clocksource */
-extern int clocksource_register(struct clocksource*);
-extern struct clocksource* clocksource_get_next(void);
-extern void clocksource_change_rating(struct clocksource *cs, int rating);
+int clocksource_register(struct clocksource*);
+void clocksource_reselect(void);
+struct clocksource* clocksource_get_next(void);
 
 #ifdef CONFIG_GENERIC_TIME_VSYSCALL
 extern void update_vsyscall(struct timespec *ts, struct clocksource *c);

@@ -196,4 +198,7 @@ static inline void update_vsyscall(struc
 }
 #endif
 
+#define clocksource_reselect()	clocksource_change_rating(&clocksource_tsc, clocksource_tsc.rating)
+extern void clocksource_change_rating(struct clocksource *cs, int rating);
+
 #endif /* _LINUX_CLOCKSOURCE_H */

Index: linux-2.6.19/kernel/timer.c
===================================================================
@@ -893,6 +893,8 @@ static int change_clocksource(void)
 		printk(KERN_INFO "Time: %s clocksource has been installed.\n",
 		       clock->name);
 		return 1;
+	} else if (clock->update_callback) {
+		return clock->update_callback();
 	}
 	return 0;
 }

@@ -959,6 +961,7 @@ void __init timekeeping_init(void)
 	write_sequnlock_irqrestore(&xtime_lock, flags);
 }
 
+
 /* flag for if timekeeping is suspended */
 static int timekeeping_suspended;
 /* time in seconds when suspend began */

Index: linux-2.6.19/arch/x86_64/kernel/tsc.c
===================================================================
@@ -46,6 +46,13 @@ static inline int check_tsc_unstable(voi
 {
 	return tsc_unstable;
 }
+
+void mark_tsc_unstable(void)
+{
+	tsc_unstable = 1;
+}
+EXPORT_SYMBOL_GPL(mark_tsc_unstable);
+
 #ifdef CONFIG_CPU_FREQ
 
 /* Frequency scaling support. Adjust the TSC based timer when the cpu frequency

@@ -174,6 +181,9 @@ __setup("notsc", notsc_setup);
 
 
 /* clock source code: */
+
+static int tsc_update_callback(void);
+
 static cycle_t read_tsc(void)
 {
 	cycle_t ret = (cycle_t)get_cycles_sync();

@@ -192,23 +202,24 @@ static struct clocksource clocksource_ts
 	.read			= read_tsc,
 	.mask			= CLOCKSOURCE_MASK(64),
 	.shift			= 22,
+	.update_callback	= tsc_update_callback,
 	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |
 				  CLOCK_SOURCE_MUST_VERIFY,
 	.vread			= vread_tsc,
 };
 
-void mark_tsc_unstable(void)
+static int tsc_update_callback(void)
 {
-	if (!tsc_unstable) {
-		tsc_unstable = 1;
-		/* Change only the rating, when not registered */
-		if (clocksource_tsc.mult)
-			clocksource_change_rating(&clocksource_tsc, 0);
-		else
-			clocksource_tsc.rating = 0;
+	int change = 0;
+
+	/* check to see if we should switch to the safe clocksource: */
+	if (clocksource_tsc.rating != 50 && check_tsc_unstable()) {
+		clocksource_tsc.rating = 50;
+		clocksource_reselect();
+		change = 1;
 	}
+	return change;
 }
-EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
 static int __init init_tsc_clocksource(void)
 {

@@ -216,7 +227,7 @@ static int __init init_tsc_clocksource(v
 		clocksource_tsc.mult = clocksource_khz2mult(cpu_khz,
 							clocksource_tsc.shift);
 		if (check_tsc_unstable())
-			clocksource_tsc.rating = 0;
+			clocksource_tsc.rating = 50;
 
 		return clocksource_register(&clocksource_tsc);
 	}

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -198,7 +198,4 @@ static inline void update_vsyscall(struc
 }
 #endif
 
-#define clocksource_reselect()	clocksource_change_rating(&clocksource_tsc, clocksource_tsc.rating)
-extern void clocksource_change_rating(struct clocksource *cs, int rating);
-
 #endif /* _LINUX_CLOCKSOURCE_H */

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Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -18,6 +18,9 @@
 /* clocksource cycle base type */
 typedef u64 cycle_t;
 
+/* XXX - Would like a better way for initializing curr_clocksource */
+extern struct clocksource clocksource_jiffies;
+
 /**
  * struct clocksource - hardware abstraction for a free running counter
  *	Provides mostly state-free accessors to the underlying hardware.

Index: linux-2.6.19/include/linux/timekeeping.h
===================================================================
@@ -0,0 +1,13 @@
+#ifndef _LINUX_TIMEKEEPING_H
+#define _LINUX_TIMEKEEPING_H
+
+#include <linux/clocksource.h>
+
+#ifndef CONFIG_GENERIC_TIME
+static inline int change_clocksource(void)
+{
+	return 0;
+}
+#endif /* !CONFIG_GENERIC_TIME */
+
+#endif /* _LINUX_TIMEKEEPING_H */

Index: linux-2.6.19/kernel/time/clocksource.c
===================================================================
@@ -29,9 +29,6 @@
 #include <linux/init.h>
 #include <linux/module.h>
 
-/* XXX - Would like a better way for initializing curr_clocksource */
-extern struct clocksource clocksource_jiffies;
-
 /*[Clocksource internal variables]---------
  * curr_clocksource:
  *	currently selected clocksource. Initialized to clocksource_jiffies.

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Index: linux-2.6.19/arch/i386/kernel/tsc.c
===================================================================
@@ -325,7 +325,7 @@ static int tsc_update_callback(void)
 	/* check to see if we should switch to the safe clocksource: */
 	if (clocksource_tsc.rating != 0 && check_tsc_unstable()) {
 		clocksource_tsc.rating = 0;
-		clocksource_reselect();
+		clocksource_rating_change(&clocksource_tsc);
 		change = 1;
 	}
 

Index: linux-2.6.19/arch/x86_64/kernel/tsc.c
===================================================================
@@ -229,7 +229,7 @@ static int tsc_update_callback(void)
 	/* check to see if we should switch to the safe clocksource: */
 	if (clocksource_tsc.rating != 50 && check_tsc_unstable()) {
 		clocksource_tsc.rating = 50;
-		clocksource_reselect();
+		clocksource_rating_change(&clocksource_tsc);
 		change = 1;
 	}
 	return change;

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -12,6 +12,8 @@
 #include <linux/timex.h>
 #include <linux/time.h>
 #include <linux/list.h>
+#include <linux/sysdev.h>
+
 #include <asm/div64.h>
 #include <asm/io.h>
 

@@ -189,9 +191,9 @@ static inline void clocksource_calculate
 
 
 /* used to install a new clocksource */
-int clocksource_register(struct clocksource*);
-void clocksource_reselect(void);
-struct clocksource* clocksource_get_next(void);
+extern struct clocksource *clocksource_get_next(void);
+extern int clocksource_register(struct clocksource*);
+extern void clocksource_rating_change(struct clocksource*);
 
 #ifdef CONFIG_GENERIC_TIME_VSYSCALL
 extern void update_vsyscall(struct timespec *ts, struct clocksource *c);

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Index: linux-2.6.19/kernel/time/clocksource.c
===================================================================
@@ -186,16 +186,12 @@ int clocksource_register(struct clocksou
 	unsigned long flags;
 
 	spin_lock_irqsave(&clocksource_lock, flags);
-	if (unlikely(!list_empty(&c->list) && __is_registered(c->name))) {
-		printk("register_clocksource: Cannot register %s clocksource. "
-		       "Already registered!", c->name);
-		ret = -EBUSY;
-	} else {
-		INIT_LIST_HEAD(&c->list);
- 		__sorted_list_add(c);
-		/* scan the registered clocksources, and pick the best one */
-		next_clocksource = select_clocksource();
-	}
+ 	__sorted_list_add(c);
+
+	/*
+	 * scan the registered clocksources, and pick the best one
+	 */
+	next_clocksource = select_clocksource();
 	spin_unlock_irqrestore(&clocksource_lock, flags);
 	return ret;
 }

@@ -212,9 +208,6 @@ void clocksource_rating_change(struct cl
 {
 	unsigned long flags;
 
-	if (unlikely(list_empty(&c->list)))
-		return;
-
   	spin_lock_irqsave(&clocksource_lock, flags);
 
 	/*

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -13,6 +13,7 @@
 #include <linux/time.h>
 #include <linux/list.h>
 #include <linux/sysdev.h>
+#include <linux/notifier.h>
 
 #include <asm/div64.h>
 #include <asm/io.h>

@@ -23,6 +24,42 @@ typedef u64 cycle_t;
 /* XXX - Would like a better way for initializing curr_clocksource */
 extern struct clocksource clocksource_jiffies;
 
+/*
+ * Allows inlined calling for notifier routines.
+ */
+extern struct atomic_notifier_head clocksource_list_notifier;
+
+/*
+ * Block notifier flags.
+ */
+#define CLOCKSOURCE_NOTIFY_REGISTER	1
+#define CLOCKSOURCE_NOTIFY_RATING	2
+#define CLOCKSOURCE_NOTIFY_FREQ		4
+
+/**
+ * clocksource_notifier_register - Registers a list change notifier
+ * @nb:		pointer to a notifier block
+ *
+ * Returns zero always.
+ */
+static inline int clocksource_notifier_register(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_register(&clocksource_list_notifier, nb);
+}
+
+/**
+ * clocksource_freq_change - Allows notification of dynamic frequency changes.
+ *
+ * Signals that a clocksource is dynamically changing it's frequency.
+ * This could happen if a clocksource becomes more/less stable.
+ */
+static inline void clocksource_freq_change(struct clocksource *c)
+{
+	atomic_notifier_call_chain(&clocksource_list_notifier,
+				   CLOCKSOURCE_NOTIFY_FREQ, c);
+}
+
+
 /**
  * struct clocksource - hardware abstraction for a free running counter
  *	Provides mostly state-free accessors to the underlying hardware.

Index: linux-2.6.19/include/linux/timekeeping.h
===================================================================
@@ -8,6 +8,9 @@ static inline int change_clocksource(voi
 {
 	return 0;
 }
+
+static inline void change_clocksource(void) { }
+
 #endif /* !CONFIG_GENERIC_TIME */
 
 #endif /* _LINUX_TIMEKEEPING_H */

Index: linux-2.6.19/kernel/time/clocksource.c
===================================================================
@@ -49,6 +49,8 @@ static DEFINE_SPINLOCK(clocksource_lock)
 static char override_name[32];
 static int finished_booting;
 
+ATOMIC_NOTIFIER_HEAD(clocksource_list_notifier);
+
 /* clocksource_done_booting - Called near the end of bootup
  *
  * Hack to avoid lots of clocksource churn at boot time

@@ -193,6 +195,10 @@ int clocksource_register(struct clocksou
 	 */
 	next_clocksource = select_clocksource();
 	spin_unlock_irqrestore(&clocksource_lock, flags);
+
+	atomic_notifier_call_chain(&clocksource_list_notifier,
+ 				   CLOCKSOURCE_NOTIFY_REGISTER, c);
+
 	return ret;
 }
 EXPORT_SYMBOL(clocksource_register);

@@ -218,6 +224,10 @@ void clocksource_rating_change(struct cl
 
 	next_clocksource = select_clocksource();
 	spin_unlock_irqrestore(&clocksource_lock, flags);
+
+	atomic_notifier_call_chain(&clocksource_list_notifier,
+				   CLOCKSOURCE_NOTIFY_RATING, c);
+
 }
 EXPORT_SYMBOL(clocksource_rating_change);
 

Index: linux-2.6.19/arch/i386/kernel/tsc.c
===================================================================
@@ -50,8 +50,7 @@ static int __init tsc_setup(char *str)
 __setup("notsc", tsc_setup);
 
 /*
- * code to mark and check if the TSC is unstable
- * due to cpufreq or due to unsynced TSCs
+ * Flag that denotes an unstable tsc and check function.
  */
 static int tsc_unstable;
 

@@ -60,12 +59,6 @@ static inline int check_tsc_unstable(voi
 	return tsc_unstable;
 }
 
-void mark_tsc_unstable(void)
-{
-	tsc_unstable = 1;
-}
-EXPORT_SYMBOL_GPL(mark_tsc_unstable);
-
 /* Accellerators for sched_clock()
  * convert from cycles(64bits) => nanoseconds (64bits)
  *  basic equation:

@@ -179,6 +172,7 @@ int recalibrate_cpu_khz(void)
 	if (cpu_has_tsc) {
 		cpu_khz = calculate_cpu_khz();
 		tsc_khz = cpu_khz;
+		mark_tsc_unstable();
 		cpu_data[0].loops_per_jiffy =
 			cpufreq_scale(cpu_data[0].loops_per_jiffy,
 					cpu_khz_old, cpu_khz);

@@ -295,7 +289,6 @@ core_initcall(cpufreq_tsc);
 /* clock source code */
 
 static unsigned long current_tsc_khz = 0;
-static int tsc_update_callback(void);
 
 static cycle_t read_tsc(void)
 {

@@ -313,32 +306,24 @@ static struct clocksource clocksource_ts
 	.mask			= CLOCKSOURCE_MASK(64),
 	.mult			= 0, /* to be set */
 	.shift			= 22,
-	.update_callback	= tsc_update_callback,
 	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |
 				  CLOCK_SOURCE_MUST_VERIFY,
 };
 
-static int tsc_update_callback(void)
+/*
+ * Code to mark if the TSC is unstable due to cpufreq or due to unsynced TSCs
+ */
+void mark_tsc_unstable(void)
 {
-	int change = 0;
-
 	/* check to see if we should switch to the safe clocksource: */
-	if (clocksource_tsc.rating != 0 && check_tsc_unstable()) {
+	if (unlikely(!tsc_unstable && clocksource_tsc.rating != 0)) {
 		clocksource_tsc.rating = 0;
 		clocksource_rating_change(&clocksource_tsc);
-		change = 1;
 	}
 
-	/* only update if tsc_khz has changed: */
-	if (current_tsc_khz != tsc_khz) {
-		current_tsc_khz = tsc_khz;
-		clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
-							clocksource_tsc.shift);
-		change = 1;
-	}
-
-	return change;
+	tsc_unstable = 1;
 }
+EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
 static int __init dmi_mark_tsc_unstable(struct dmi_system_id *d)
 {

Index: linux-2.6.19/arch/x86_64/kernel/tsc.c
===================================================================
@@ -47,11 +47,6 @@ static inline int check_tsc_unstable(voi
 	return tsc_unstable;
 }
 
-void mark_tsc_unstable(void)
-{
-	tsc_unstable = 1;
-}
-EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
 #ifdef CONFIG_CPU_FREQ
 

@@ -182,8 +177,6 @@ __setup("notsc", notsc_setup);
 
 /* clock source code: */
 
-static int tsc_update_callback(void);
-
 static cycle_t read_tsc(void)
 {
 	cycle_t ret = (cycle_t)get_cycles_sync();

@@ -202,24 +195,22 @@ static struct clocksource clocksource_ts
 	.read			= read_tsc,
 	.mask			= CLOCKSOURCE_MASK(64),
 	.shift			= 22,
-	.update_callback	= tsc_update_callback,
 	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |
 				  CLOCK_SOURCE_MUST_VERIFY,
 	.vread			= vread_tsc,
 };
 
-static int tsc_update_callback(void)
+void mark_tsc_unstable(void)
 {
-	int change = 0;
-
 	/* check to see if we should switch to the safe clocksource: */
-	if (clocksource_tsc.rating != 50 && check_tsc_unstable()) {
+	if (unlikely(!tsc_unstable && clocksource_tsc.rating != 50)) {
 		clocksource_tsc.rating = 50;
 		clocksource_rating_change(&clocksource_tsc);
-		change = 1;
 	}
-	return change;
+
+	tsc_unstable = 1;
 }
+EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
 static int __init init_tsc_clocksource(void)
 {

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -86,7 +86,6 @@ static inline void clocksource_freq_chan
  *			subtraction of non 64 bit counters
  * @mult:		cycle to nanosecond multiplier
  * @shift:		cycle to nanosecond divisor (power of two)
- * @update_callback:	called when safe to alter clocksource values
  * @flags:		flags describing special properties
  * @vread:		vsyscall based read
  * @cycle_interval:	Used internally by timekeeping core, please ignore.

@@ -100,7 +99,6 @@ struct clocksource {
 	cycle_t mask;
 	u32 mult;
 	u32 shift;
-	int (*update_callback)(void);
 	unsigned long flags;
 	cycle_t (*vread)(void);
 

Index: linux-2.6.19/include/linux/timekeeping.h
===================================================================
@@ -10,6 +10,7 @@ static inline int change_clocksource(voi
 }
 
 static inline void change_clocksource(void) { }
+static inline void timekeeping_init_notifier(void) { }
 
 #endif /* !CONFIG_GENERIC_TIME */
 

Index: linux-2.6.19/kernel/time/timekeeping.c
===================================================================
@@ -39,6 +39,7 @@ static unsigned long timekeeping_suspend
  * Clock used for timekeeping
  */
 struct clocksource *clock = &clocksource_jiffies;
+atomic_t clock_recalc_interval = ATOMIC_INIT(0);
 
 #ifdef CONFIG_GENERIC_TIME
 /**

@@ -176,8 +177,9 @@ static int change_clocksource(void)
 		printk(KERN_INFO "Time: %s clocksource has been installed.\n",
 		       clock->name);
 		return 1;
-	} else if (clock->update_callback) {
-		return clock->update_callback();
+	} else if (unlikely(atomic_read(&clock_recalc_interval))) {
+		atomic_set(&clock_recalc_interval, 0);
+		return 1;
 	}
 	return 0;
 }

@@ -199,6 +201,29 @@ int timekeeping_is_continuous(void)
 
 	return ret;
 }
+
+static int
+clocksource_callback(struct notifier_block *nb, unsigned long op, void *c)
+{
+	if (c == clock && op == CLOCKSOURCE_NOTIFY_FREQ &&
+	    !atomic_read(&clock_recalc_interval))
+		atomic_inc(&clock_recalc_interval);
+
+	return 0;
+}
+
+static struct notifier_block clocksource_nb = {
+	.notifier_call = clocksource_callback,
+};
+
+void __init timekeeping_init_notifier(void)
+{
+	/*
+	 * Needs to be done early, incase a clock is unstable
+	 * early.
+	 */
+	clocksource_notifier_register(&clocksource_nb);
+}
 #endif /* CONFIG_GENERIC_TIME */
 
 /**

@@ -237,6 +262,9 @@ void __init timekeeping_init(void)
 		-xtime.tv_sec, -xtime.tv_nsec);
 
 	write_sequnlock_irqrestore(&xtime_lock, flags);
+
+	timekeeping_init_notifier();
+
 }
 
 

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -25,6 +25,11 @@ typedef u64 cycle_t;
 extern struct clocksource clocksource_jiffies;
 
 /*
+ * Atomic signal that is specific to timekeeping.
+ */
+extern atomic_t clock_check;
+
+/*
  * Allows inlined calling for notifier routines.
  */
 extern struct atomic_notifier_head clocksource_list_notifier;

Index: linux-2.6.19/include/linux/timekeeping.h
===================================================================
@@ -4,10 +4,6 @@
 #include <linux/clocksource.h>
 
 #ifndef CONFIG_GENERIC_TIME
-static inline int change_clocksource(void)
-{
-	return 0;
-}
 
 static inline void change_clocksource(void) { }
 static inline void timekeeping_init_notifier(void) { }

Index: linux-2.6.19/kernel/time/clocksource.c
===================================================================
@@ -50,6 +50,7 @@ static char override_name[32];
 static int finished_booting;
 
 ATOMIC_NOTIFIER_HEAD(clocksource_list_notifier);
+atomic_t clock_check = ATOMIC_INIT(0);
 
 /* clocksource_done_booting - Called near the end of bootup
  *

@@ -58,6 +59,8 @@ ATOMIC_NOTIFIER_HEAD(clocksource_list_no
 static int __init clocksource_done_booting(void)
 {
 	finished_booting = 1;
+	/* Check for a new clock now */
+	atomic_inc(&clock_check);
 	return 0;
 }
 

@@ -285,6 +288,9 @@ static ssize_t sysfs_override_clocksourc
 	/* try to select it: */
 	next_clocksource = select_clocksource();
 
+	/* Signal that there is a new clocksource */
+	atomic_inc(&clock_check);
+
 	spin_unlock_irq(&clocksource_lock);
 
 	return ret;

96 lines not on this page · raw message

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -234,6 +234,18 @@ static inline void clocksource_calculate
 extern struct clocksource *clocksource_get_next(void);
 extern int clocksource_register(struct clocksource*);
 extern void clocksource_rating_change(struct clocksource*);
+extern struct clocksource * clocksource_get_clock(char*);
+
+/**
+ * clocksource_get_best_clock - Finds highest rated clocksource
+ *
+ * Returns the highest rated clocksource. If none are register the
+ * jiffies clock is returned.
+ */
+static inline struct clocksource * clocksource_get_best_clock(void)
+{
+	return clocksource_get_clock(NULL);
+}
 
 #ifdef CONFIG_GENERIC_TIME_VSYSCALL
 extern void update_vsyscall(struct timespec *ts, struct clocksource *c);

Index: linux-2.6.19/kernel/time/clocksource.c
===================================================================
@@ -132,6 +132,24 @@ static inline struct clocksource * __get
 }
 
 /**
+ * clocksource_get_clock - Finds a specific clocksource
+ * @name:		name of the clocksource to return
+ *
+ * Returns the clocksource if registered, zero otherwise.
+ */
+struct clocksource * clocksource_get_clock(char * name)
+{
+	struct clocksource * ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&clocksource_lock, flags);
+	ret = __get_clock(name);
+	spin_unlock_irqrestore(&clocksource_lock, flags);
+	return ret;
+}
+
+
+/**
  * select_clocksource - Finds the best registered clocksource.
  *
  * Private function. Must hold clocksource_lock when called.

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -25,9 +25,9 @@ typedef u64 cycle_t;
 extern struct clocksource clocksource_jiffies;
 
 /*
- * Atomic signal that is specific to timekeeping.
+ * Sysfs device extern, for registering clocksources under the same sysfs dir.
  */
-extern atomic_t clock_check;
+extern struct sys_device clocksource_sys_device;
 
 /*
  * Allows inlined calling for notifier routines.

@@ -231,7 +231,6 @@ static inline void clocksource_calculate
 
 
 /* used to install a new clocksource */
-extern struct clocksource *clocksource_get_next(void);
 extern int clocksource_register(struct clocksource*);
 extern void clocksource_rating_change(struct clocksource*);
 extern struct clocksource * clocksource_get_clock(char*);

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161 lines not on this page · raw message

Index: linux-2.6.19/arch/i386/kernel/hpet.c
===================================================================
@@ -315,7 +315,7 @@ static int __init init_hpet_clocksource(
 	return clocksource_register(&clocksource_hpet);
 }
 
-module_init(init_hpet_clocksource);
+clocksource_initcall(init_hpet_clocksource);
 
 #ifdef CONFIG_HPET_EMULATE_RTC
 

Index: linux-2.6.19/arch/i386/kernel/i8253.c
===================================================================
@@ -195,4 +195,4 @@ static int __init init_pit_clocksource(v
 	clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20);
 	return clocksource_register(&clocksource_pit);
 }
-module_init(init_pit_clocksource);
+clocksource_initcall(init_pit_clocksource);

Index: linux-2.6.19/arch/i386/kernel/tsc.c
===================================================================
@@ -458,4 +458,4 @@ static int __init init_tsc_clocksource(v
 	return 0;
 }
 
-module_init(init_tsc_clocksource);
+clocksource_initcall(init_tsc_clocksource);

Index: linux-2.6.19/arch/x86_64/kernel/hpet.c
===================================================================
@@ -508,4 +508,4 @@ static int __init init_hpet_clocksource(
 	return clocksource_register(&clocksource_hpet);
 }
 
-module_init(init_hpet_clocksource);
+clocksource_initcall(init_hpet_clocksource);

Index: linux-2.6.19/arch/x86_64/kernel/tsc.c
===================================================================
@@ -224,5 +224,4 @@ static int __init init_tsc_clocksource(v
 	}
 	return 0;
 }
-
-module_init(init_tsc_clocksource);
+clocksource_initcall(init_tsc_clocksource);

Index: linux-2.6.19/drivers/clocksource/acpi_pm.c
===================================================================
@@ -214,4 +214,10 @@ pm_good:
 	return clocksource_register(&clocksource_acpi_pm);
 }
 
-module_init(init_acpi_pm_clocksource);
+/*
+ * This clocksource is removed from the clocksource_initcall
+ * macro since it's mandatory for it to be in fs_initcall as the
+ * highest initcall level, or else it doesn't work properly with
+ * it's PCI fix ups.
+ */
+fs_initcall(init_acpi_pm_clocksource);

Index: linux-2.6.19/drivers/clocksource/cyclone.c
===================================================================
@@ -116,4 +116,4 @@ static int __init init_cyclone_clocksour
 	return clocksource_register(&clocksource_cyclone);
 }
 
-module_init(init_cyclone_clocksource);
+clocksource_initcall(init_cyclone_clocksource);

Index: linux-2.6.19/drivers/clocksource/scx200_hrt.c
===================================================================
@@ -94,7 +94,7 @@ static int __init init_hrt_clocksource(v
 	return clocksource_register(&cs_hrt);
 }
 
-module_init(init_hrt_clocksource);
+clocksource_initcall(init_hrt_clocksource);
 
 MODULE_AUTHOR("Jim Cromie <[email protected]>");
 MODULE_DESCRIPTION("clocksource on SCx200 HiRes Timer");

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -41,6 +41,12 @@ extern struct atomic_notifier_head clock
 #define CLOCKSOURCE_NOTIFY_RATING	2
 #define CLOCKSOURCE_NOTIFY_FREQ		4
 
+/*
+ * Defined so the initcall can be changes without touching
+ * every clocksource in the system.
+ */
+#define clocksource_initcall(x)		fs_initcall(x)
+
 /**
  * clocksource_notifier_register - Registers a list change notifier
  * @nb:		pointer to a notifier block

Index: linux-2.6.19/kernel/time/clocksource.c
===================================================================
@@ -38,22 +38,9 @@
  */
 static LIST_HEAD(clocksource_list);
 static DEFINE_SPINLOCK(clocksource_lock);
-static int finished_booting;
 
 ATOMIC_NOTIFIER_HEAD(clocksource_list_notifier);
 
-/* clocksource_done_booting - Called near the end of bootup
- *
- * Hack to avoid lots of clocksource churn at boot time
- */
-static int __init clocksource_done_booting(void)
-{
-	finished_booting = 1;
-	return 0;
-}
-
-late_initcall(clocksource_done_booting);
-
 /**
  * __is_registered - Returns a clocksource if it's registered
  * @name:		name of the clocksource to return

Index: linux-2.6.19/kernel/time/jiffies.c
===================================================================
@@ -69,4 +69,4 @@ static int __init init_jiffies_clocksour
 	return clocksource_register(&clocksource_jiffies);
 }
 
-module_init(init_jiffies_clocksource);
+clocksource_initcall(init_jiffies_clocksource);

Index: linux-2.6.19/kernel/time/tick-sched.c
===================================================================
@@ -540,6 +540,14 @@ int tick_check_oneshot_change(int allow_
 {
 	struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
 
+	/*
+	 * HRT or Dynamic tick can't be started during init, but it's possible
+	 * for generic time to switch to a good clock during init. So
+	 * explicitly check that we are't still booting here.
+	 */
+	if (system_state == SYSTEM_BOOTING)
+		return 0;
+
 	if (!test_and_clear_bit(0, &ts->check_clocks))
 		return 0;
 

Index: linux-2.6.19/kernel/time/timekeeping.c
===================================================================
@@ -318,14 +318,6 @@ static __init int timekeeping_init_sysfs
 device_initcall(timekeeping_init_sysfs);
 #endif /* CONFIG_SYSFS */
 
-static int __init timekeeping_early_clockswitch(void)
-{
-	atomic_inc(&clock_check);
-	return 0;
-}
-
-late_initcall(timekeeping_early_clockswitch);
-
 /**
  * boot_override_clocksource - boot clock override
  * @str:	override name

@@ -471,6 +463,13 @@ static int __init timekeeping_init_devic
 	if (!error)
 		error = sysdev_register(&device_timer);
 
+#ifdef CONFIG_GENERIC_TIME
+	/*
+	 * Now we signal to switch to a high-res clock.
+	 */
+	atomic_inc(&clock_check);
+#endif
+
 	return error;
 }
 

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -235,6 +235,12 @@ static inline void clocksource_calculate
 	c->xtime_interval = (u64)c->cycle_interval * c->mult;
 }
 
+#define CLOCKSOURCE_NOT_CONTINUOUS	1
+#define CLOCKSOURCE_UNSTABLE		2
+#define CLOCKSOURCE_NOT_ATOMIC		4
+#define CLOCKSOURCE_UNDER_32BITS	8
+#define CLOCKSOURCE_64BITS		16
+#define CLOCKSOURCE_PM_AFFECTED		32
 
 /* used to install a new clocksource */
 extern int clocksource_register(struct clocksource*);

Index: linux-2.6.19/arch/arm/mach-imx/time.c
===================================================================
@@ -87,7 +87,6 @@ static struct clocksource clocksource_im
 	.read		= imx_get_cycles,
 	.mask		= 0xFFFFFFFF,
 	.shift 		= 20,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 static int __init imx_clocksource_init(void)

Index: linux-2.6.19/arch/arm/mach-ixp4xx/common.c
===================================================================
@@ -395,7 +395,6 @@ static struct clocksource clocksource_ix
 	.read		= ixp4xx_get_cycles,
 	.mask		= CLOCKSOURCE_MASK(32),
 	.shift 		= 20,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 unsigned long ixp4xx_timer_freq = FREQ;

Index: linux-2.6.19/arch/arm/mach-netx/time.c
===================================================================
@@ -62,7 +62,6 @@ static struct clocksource clocksource_ne
 	.read		= netx_get_cycles,
 	.mask		= CLOCKSOURCE_MASK(32),
 	.shift 		= 20,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 /*

Index: linux-2.6.19/arch/arm/mach-pxa/time.c
===================================================================
@@ -112,7 +112,6 @@ static struct clocksource clocksource_px
 	.read           = pxa_get_cycles,
 	.mask           = CLOCKSOURCE_MASK(32),
 	.shift          = 20,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 static void __init pxa_timer_init(void)

Index: linux-2.6.19/arch/avr32/kernel/time.c
===================================================================
@@ -37,7 +37,6 @@ static struct clocksource clocksource_av
 	.read		= read_cycle_count,
 	.mask		= CLOCKSOURCE_MASK(32),
 	.shift		= 16,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 /*

Index: linux-2.6.19/arch/i386/kernel/hpet.c
===================================================================
@@ -287,7 +287,6 @@ static struct clocksource clocksource_hp
 	.read		= read_hpet,
 	.mask		= HPET_MASK,
 	.shift		= HPET_SHIFT,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 static int __init init_hpet_clocksource(void)

Index: linux-2.6.19/arch/i386/kernel/i8253.c
===================================================================
@@ -183,6 +183,7 @@ static struct clocksource clocksource_pi
 	.rating = 110,
 	.read	= pit_read,
 	.mask	= CLOCKSOURCE_MASK(32),
+	.flags	= CLOCKSOURCE_NOT_ATOMIC,
 	.mult	= 0,
 	.shift	= 20,
 };

Index: linux-2.6.19/arch/i386/kernel/tsc.c
===================================================================
@@ -306,8 +306,7 @@ static struct clocksource clocksource_ts
 	.mask			= CLOCKSOURCE_MASK(64),
 	.mult			= 0, /* to be set */
 	.shift			= 22,
-	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |
-				  CLOCK_SOURCE_MUST_VERIFY,
+	.flags			= CLOCKSOURCE_64BITS | CLOCKSOURCE_PM_AFFECTED,
 };
 
 /*

@@ -316,10 +315,8 @@ static struct clocksource clocksource_ts
 void mark_tsc_unstable(void)
 {
 	/* check to see if we should switch to the safe clocksource: */
-	if (unlikely(!tsc_unstable && clocksource_tsc.rating != 0)) {
-		clocksource_tsc.rating = 0;
-		clocksource_rating_change(&clocksource_tsc);
-	}
+	if (unlikely(!tsc_unstable))
+		clocksource_mark_unstable(&clocksource_tsc);
 
 	tsc_unstable = 1;
 }

@@ -434,17 +431,19 @@ static int __init init_tsc_clocksource(v
 		/* check blacklist */
 		dmi_check_system(bad_tsc_dmi_table);
 
-		if (unsynchronized_tsc()) /* mark unstable if unsynced */
+		if (unsynchronized_tsc()) { /* mark unstable if unsynced */
 			mark_tsc_unstable();
+			clocksource_tsc.flags |= CLOCKSOURCE_UNSTABLE;
+		}
 		check_geode_tsc_reliable();
 		current_tsc_khz = tsc_khz;
 		clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
 							clocksource_tsc.shift);
-		/* lower the rating if we already know its unstable: */
-		if (check_tsc_unstable()) {
-			clocksource_tsc.rating = 0;
-			clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
-		}
+
+		/* flags as unstable if we already know its unstable: */
+		if (check_tsc_unstable())
+			clocksource_tsc.flags |= CLOCKSOURCE_UNSTABLE |
+						 CLOCKSOURCE_NOT_CONTINUOUS;
 
 		init_timer(&verify_tsc_freq_timer);
 		verify_tsc_freq_timer.function = verify_tsc_freq;

Index: linux-2.6.19/arch/i386/kernel/vmitime.c
===================================================================
@@ -115,7 +115,7 @@ static struct clocksource clocksource_vm
 	.mask			= CLOCKSOURCE_MASK(64),
 	.mult			= 0, /* to be set */
 	.shift			= 22,
-	.flags			= CLOCK_SOURCE_IS_CONTINUOUS,
+	.flags			= CLOCKSOURCE_64BITS,
 };
 
 

Index: linux-2.6.19/arch/mips/kernel/time.c
===================================================================
@@ -307,7 +307,6 @@ static unsigned int __init calibrate_hpt
 struct clocksource clocksource_mips = {
 	.name		= "MIPS",
 	.mask		= 0xffffffff,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 static void __init init_mips_clocksource(void)

Index: linux-2.6.19/arch/x86_64/kernel/hpet.c
===================================================================
@@ -470,7 +470,6 @@ struct clocksource clocksource_hpet = {
 	.mask		= (cycle_t)HPET_MASK,
 	.mult		= 0, /* set below */
 	.shift		= HPET_SHIFT,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 	.vread		= vread_hpet,
 };
 

Index: linux-2.6.19/arch/x86_64/kernel/tsc.c
===================================================================
@@ -195,18 +195,15 @@ static struct clocksource clocksource_ts
 	.read			= read_tsc,
 	.mask			= CLOCKSOURCE_MASK(64),
 	.shift			= 22,
-	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |
-				  CLOCK_SOURCE_MUST_VERIFY,
+	.flags                  = CLOCKSOURCE_64BITS | CLOCKSOURCE_PM_AFFECTED,
 	.vread			= vread_tsc,
 };
 
 void mark_tsc_unstable(void)
 {
 	/* check to see if we should switch to the safe clocksource: */
-	if (unlikely(!tsc_unstable && clocksource_tsc.rating != 50)) {
-		clocksource_tsc.rating = 50;
-		clocksource_rating_change(&clocksource_tsc);
-	}
+	if (unlikely(!tsc_unstable && clocksource_tsc.rating != 50))
+		clocksource_tsc.flags |= CLOCKSOURCE_UNSTABLE;
 
 	tsc_unstable = 1;
 }

@@ -218,7 +215,7 @@ static int __init init_tsc_clocksource(v
 		clocksource_tsc.mult = clocksource_khz2mult(cpu_khz,
 							clocksource_tsc.shift);
 		if (check_tsc_unstable())
-			clocksource_tsc.rating = 50;
+			clocksource_tsc.flags |= CLOCKSOURCE_UNSTABLE;
 
 		return clocksource_register(&clocksource_tsc);
 	}

Index: linux-2.6.19/drivers/clocksource/acpi_pm.c
===================================================================
@@ -73,7 +73,7 @@ static struct clocksource clocksource_ac
 	.mask		= (cycle_t)ACPI_PM_MASK,
 	.mult		= 0, /*to be caluclated*/
 	.shift		= 22,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+	.flags		= CLOCKSOURCE_UNDER_32BITS,
 
 };
 

Index: linux-2.6.19/drivers/clocksource/cyclone.c
===================================================================
@@ -31,7 +31,6 @@ static struct clocksource clocksource_cy
 	.mask		= CYCLONE_TIMER_MASK,
 	.mult		= 10,
 	.shift		= 0,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 static int __init init_cyclone_clocksource(void)

Index: linux-2.6.19/drivers/clocksource/scx200_hrt.c
===================================================================
@@ -57,7 +57,6 @@ static struct clocksource cs_hrt = {
 	.rating		= 250,
 	.read		= read_hrt,
 	.mask		= CLOCKSOURCE_MASK(32),
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 	/* mult, shift are set based on mhz27 flag */
 };
 

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -30,6 +30,11 @@ extern struct clocksource clocksource_ji
 extern struct sys_device clocksource_sys_device;
 
 /*
+ * Read function type.
+ */
+typedef cycle_t (*clock_read_t)(void);
+
+/*
  * Allows inlined calling for notifier routines.
  */
 extern struct atomic_notifier_head clocksource_list_notifier;

@@ -40,6 +45,7 @@ extern struct atomic_notifier_head clock
 #define CLOCKSOURCE_NOTIFY_REGISTER	1
 #define CLOCKSOURCE_NOTIFY_RATING	2
 #define CLOCKSOURCE_NOTIFY_FREQ		4
+#define CLOCKSOURCE_NOTIFY_UNSTABLE	8
 
 /*
  * Defined so the initcall can be changes without touching

@@ -119,12 +125,6 @@ struct clocksource {
 	s64 error;
 };
 
-/*
- * Clock source flags bits::
- */
-#define CLOCK_SOURCE_IS_CONTINUOUS	0x01
-#define CLOCK_SOURCE_MUST_VERIFY	0x02
-
 /* simplify initialization of mask field */
 #define CLOCKSOURCE_MASK(bits) (cycle_t)(bits<64 ? ((1ULL<<bits)-1) : -1)
 

@@ -235,6 +235,9 @@ static inline void clocksource_calculate
 	c->xtime_interval = (u64)c->cycle_interval * c->mult;
 }
 
+/*
+ * Clocksource flags
+ */
 #define CLOCKSOURCE_NOT_CONTINUOUS	1
 #define CLOCKSOURCE_UNSTABLE		2
 #define CLOCKSOURCE_NOT_ATOMIC		4

@@ -243,9 +246,25 @@ static inline void clocksource_calculate
 #define CLOCKSOURCE_PM_AFFECTED		32
 
 /* used to install a new clocksource */
+extern void clocksource_mark_unstable(struct clocksource *);
+extern struct clocksource *clocksource_get_unstable(void);
 extern int clocksource_register(struct clocksource*);
 extern void clocksource_rating_change(struct clocksource*);
-extern struct clocksource * clocksource_get_clock(char*);
+extern struct clocksource * clocksource_get_clock(char*, unsigned long);
+
+
+/**
+ * clocksource_get_masked_clock - Finds highest rated clocksource w/o mask
+ * @mask:		Clocksource features that are not wanted.
+ *
+ * Returns the highest rated clocksource that doesn't have any of the bits set
+ * in mask. If none are register the jiffies clock is returned. If all the clocks
+ * have the mask bits set, then NULL is returned.
+ */
+static inline struct clocksource * clocksource_get_masked_clock(unsigned long mask)
+{
+	return clocksource_get_clock(NULL, mask);
+}
 
 /**
  * clocksource_get_best_clock - Finds highest rated clocksource

@@ -255,7 +274,7 @@ extern struct clocksource * clocksource_
  */
 static inline struct clocksource * clocksource_get_best_clock(void)
 {
-	return clocksource_get_clock(NULL);
+	return clocksource_get_clock(NULL, 0);
 }
 
 #ifdef CONFIG_GENERIC_TIME_VSYSCALL

104 lines not on this page · raw message

Index: linux-2.6.19/kernel/time/jiffies.c
===================================================================
@@ -62,6 +62,7 @@ struct clocksource clocksource_jiffies =
 	.mask		= 0xffffffff, /*32bits*/
 	.mult		= NSEC_PER_JIFFY << JIFFIES_SHIFT, /* details above */
 	.shift		= JIFFIES_SHIFT,
+	.flags		= CLOCKSOURCE_NOT_CONTINUOUS, /* not free running */
 };
 
 static int __init init_jiffies_clocksource(void)

Index: linux-2.6.19/kernel/time/timekeeping.c
===================================================================
@@ -181,9 +181,12 @@ static void timekeeping_change_clocksour
 	u64 nsec;
 
 	if (!*override_name)
-		new = clocksource_get_clock(NULL);
+		/*
+		 * Mask off unstable clocks.
+		 */
+		new = clocksource_get_masked_clock(CLOCKSOURCE_UNSTABLE);
 	else
-		new = clocksource_get_clock(override_name);
+		new = clocksource_get_clock(override_name, 0);
 
 	if (clock != new) {
 		now = clocksource_read(new);

@@ -216,7 +219,7 @@ int timekeeping_is_continuous(void)
 	do {
 		seq = read_seqbegin(&xtime_lock);
 
-		ret = clock->flags & CLOCK_SOURCE_IS_CONTINUOUS;
+		ret = !(clock->flags & CLOCKSOURCE_NOT_CONTINUOUS);
 
 	} while (read_seqretry(&xtime_lock, seq));
 

@@ -231,7 +234,7 @@ clocksource_callback(struct notifier_blo
 
 	switch (op) {
 		case CLOCKSOURCE_NOTIFY_FREQ:
-		case CLOCKSOURCE_NOTIFY_RATING:
+		case CLOCKSOURCE_NOTIFY_UNSTABLE:
 			atomic_inc(&clock_check);
 	}
 

Index: linux-2.6.19/arch/i386/kernel/tsc.c
===================================================================
@@ -343,47 +343,59 @@ static struct dmi_system_id __initdata b
 	 {}
 };
 
-#define TSC_FREQ_CHECK_INTERVAL (10*MSEC_PER_SEC) /* 10sec in MS */
+#define WATCHDOG_TRESHOLD (NSEC_PER_SEC >> 4)
+#define TSC_FREQ_CHECK_INTERVAL (MSEC_PER_SEC/2)
 static struct timer_list verify_tsc_freq_timer;
+struct clocksource *verify_clock;
 
 /* XXX - Probably should add locking */
 static void verify_tsc_freq(unsigned long unused)
 {
-	static u64 last_tsc;
-	static unsigned long last_jiffies;
-
-	u64 now_tsc, interval_tsc;
-	unsigned long now_jiffies, interval_jiffies;
+	static cycle_t last_tsc, last_verify;
 
+	cycle_t now_tsc, verify_clock_now, interval;
+	s64 nsecs;
 
 	if (check_tsc_unstable())
 		return;
 
-	rdtscll(now_tsc);
-	now_jiffies = jiffies;
+	if (unlikely(system_state != SYSTEM_RUNNING))
+		goto out_timer;
 
-	if (!last_jiffies) {
-		goto out;
+	if (unlikely(!verify_clock)) {
+		verify_clock =
+			clocksource_get_masked_clock(CLOCKSOURCE_PM_AFFECTED);
+		printk("TSC: selected %s clocksource for TSC verification.\n",
+		       verify_clock->name);
 	}
 
-	interval_jiffies = now_jiffies - last_jiffies;
-	interval_tsc = now_tsc - last_tsc;
-	interval_tsc *= HZ;
-	do_div(interval_tsc, cpu_khz*1000);
+	now_tsc = clocksource_read(&clocksource_tsc);
+	verify_clock_now = clocksource_read(verify_clock);
+
+	if (!last_tsc)
+		goto out;
 
-	if (interval_tsc < (interval_jiffies * 3 / 4)) {
+	interval = clocksource_subtract(verify_clock, verify_clock_now,
+					last_verify);
+	nsecs = cyc2ns(verify_clock, interval);
+
+	interval = clocksource_subtract(&clocksource_tsc, now_tsc, last_tsc);
+	nsecs -= cyc2ns(&clocksource_tsc, interval);
+
+	if (nsecs > WATCHDOG_TRESHOLD) {
 		printk("TSC appears to be running slowly. "
-			"Marking it as unstable\n");
+		       "Marking it as unstable");
 		mark_tsc_unstable();
 		return;
 	}
 
 out:
-	last_tsc = now_tsc;
-	last_jiffies = now_jiffies;
+  	last_tsc = now_tsc;
+	last_verify = verify_clock_now;
+out_timer:
 	/* set us up to go off on the next interval: */
 	mod_timer(&verify_tsc_freq_timer,
-		jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL));
+		  jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL));
 }
 
 /*

@@ -444,7 +456,10 @@ static int __init init_tsc_clocksource(v
 		if (check_tsc_unstable())
 			clocksource_tsc.flags |= CLOCKSOURCE_UNSTABLE |
 						 CLOCKSOURCE_NOT_CONTINUOUS;
-
+		/*
+		 * The verify routine will select the right clock after the
+		 * system boots fully.
+		 */
 		init_timer(&verify_tsc_freq_timer);
 		verify_tsc_freq_timer.function = verify_tsc_freq;
 		verify_tsc_freq_timer.expires =

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
@@ -207,6 +207,22 @@ static inline s64 cyc2ns(struct clocksou
 }
 
 /**
+ * clocksource_subtract - Subtract two cycle_t timestamps
+ * @cs:		Clocksource the timestamp came from
+ * @stop:	Stop timestamp
+ * @start:	Start timestamp
+ *
+ * This subtract accounts for rollover by using the clocksource mask.
+ * The clock can roll over only once, after that this subtract will not
+ * work properly.
+ */
+static inline s64 clocksource_subtract(struct clocksource* cs, cycle_t stop,
+				       cycle_t start)
+{
+	return ((stop - start) & cs->mask);
+}
+
+/**
  * clocksource_calculate_interval - Calculates a clocksource interval struct
  *
  * @c:		Pointer to clocksource.