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Subject[patch 17/46] clocksource: Remove the update callback
From: Thomas Gleixner <tglx@linutronix.de>

The clocksource code allows direct updates of the rating
of a given clocksource now. Change TSC unstable tracking to
use this interface and remove the update callback.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
arch/i386/kernel/tsc.c | 51 ++++++++++++++------------------------------
include/linux/clocksource.h | 8 ++----
kernel/timer.c | 2 -
3 files changed, 20 insertions(+), 41 deletions(-)

Index: linux-2.6.20-rc4-mm1-bo/arch/i386/kernel/tsc.c
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/arch/i386/kernel/tsc.c
+++ linux-2.6.20-rc4-mm1-bo/arch/i386/kernel/tsc.c
@@ -60,12 +60,6 @@ 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:
@@ -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)
{
@@ -313,38 +306,28 @@ 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)
+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()) {
- 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;
+ 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;
}
-
- 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);
- mark_tsc_unstable();
+ tsc_unstable = 1;
return 0;
}

@@ -416,11 +399,12 @@ __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)
- return 0;
-
- /* assume multi socket systems are not synchronized: */
- return num_possible_cpus() > 1;
+ 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;
}

static int __init init_tsc_clocksource(void)
@@ -430,8 +414,7 @@ static int __init init_tsc_clocksource(v
/* check blacklist */
dmi_check_system(bad_tsc_dmi_table);

- if (unsynchronized_tsc()) /* mark unstable if unsynced */
- mark_tsc_unstable();
+ unsynchronized_tsc();
current_tsc_khz = tsc_khz;
clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
clocksource_tsc.shift);
Index: linux-2.6.20-rc4-mm1-bo/include/linux/clocksource.h
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/include/linux/clocksource.h
+++ linux-2.6.20-rc4-mm1-bo/include/linux/clocksource.h
@@ -44,7 +44,6 @@ 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
* @cycle_interval: Used internally by timekeeping core, please ignore.
* @xtime_interval: Used internally by timekeeping core, please ignore.
@@ -57,7 +56,6 @@ struct clocksource {
cycle_t mask;
u32 mult;
u32 shift;
- int (*update_callback)(void);
unsigned long flags;

/* timekeeping specific data, ignore */
@@ -184,8 +182,8 @@ 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 int clocksource_register(struct clocksource*);
+extern struct clocksource* clocksource_get_next(void);
+extern void clocksource_change_rating(struct clocksource *, int rating);

#endif /* _LINUX_CLOCKSOURCE_H */
Index: linux-2.6.20-rc4-mm1-bo/kernel/timer.c
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/kernel/timer.c
+++ linux-2.6.20-rc4-mm1-bo/kernel/timer.c
@@ -848,8 +848,6 @@ 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;
}
--

-
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