Commit 5d2a4e91 authored by Pavel Tatashin's avatar Pavel Tatashin Committed by Thomas Gleixner

sched/clock: Move sched clock initialization and merge with generic clock

sched_clock_postinit() initializes a generic clock on systems where no
other clock is provided. This function may be called only after
timekeeping_init().

Rename sched_clock_postinit to generic_clock_inti() and call it from
sched_clock_init(). Move the call for sched_clock_init() until after
time_init().
Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarPavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: steven.sistare@oracle.com
Cc: daniel.m.jordan@oracle.com
Cc: linux@armlinux.org.uk
Cc: schwidefsky@de.ibm.com
Cc: heiko.carstens@de.ibm.com
Cc: john.stultz@linaro.org
Cc: sboyd@codeaurora.org
Cc: hpa@zytor.com
Cc: douly.fnst@cn.fujitsu.com
Cc: prarit@redhat.com
Cc: feng.tang@intel.com
Cc: pmladek@suse.com
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: linux-s390@vger.kernel.org
Cc: boris.ostrovsky@oracle.com
Cc: jgross@suse.com
Cc: pbonzini@redhat.com
Link: https://lkml.kernel.org/r/20180719205545.16512-23-pasha.tatashin@oracle.com
parent 4763f03d
......@@ -9,17 +9,16 @@
#define LINUX_SCHED_CLOCK
#ifdef CONFIG_GENERIC_SCHED_CLOCK
extern void sched_clock_postinit(void);
extern void generic_sched_clock_init(void);
extern void sched_clock_register(u64 (*read)(void), int bits,
unsigned long rate);
#else
static inline void sched_clock_postinit(void) { }
static inline void generic_sched_clock_init(void) { }
static inline void sched_clock_register(u64 (*read)(void), int bits,
unsigned long rate)
{
;
}
#endif
......
......@@ -79,7 +79,7 @@
#include <linux/pti.h>
#include <linux/blkdev.h>
#include <linux/elevator.h>
#include <linux/sched_clock.h>
#include <linux/sched/clock.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/context_tracking.h>
......@@ -642,7 +642,7 @@ asmlinkage __visible void __init start_kernel(void)
softirq_init();
timekeeping_init();
time_init();
sched_clock_postinit();
sched_clock_init();
printk_safe_init();
perf_event_init();
profile_init();
......
......@@ -53,6 +53,7 @@
*
*/
#include "sched.h"
#include <linux/sched_clock.h>
/*
* Scheduler clock - returns current time in nanosec units.
......@@ -68,11 +69,6 @@ EXPORT_SYMBOL_GPL(sched_clock);
__read_mostly int sched_clock_running;
void sched_clock_init(void)
{
sched_clock_running = 1;
}
#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
/*
* We must start with !__sched_clock_stable because the unstable -> stable
......@@ -199,6 +195,15 @@ void clear_sched_clock_stable(void)
__clear_sched_clock_stable();
}
static void __sched_clock_gtod_offset(void)
{
__gtod_offset = (sched_clock() + __sched_clock_offset) - ktime_get_ns();
}
void __init sched_clock_init(void)
{
sched_clock_running = 1;
}
/*
* We run this as late_initcall() such that it runs after all built-in drivers,
* notably: acpi_processor and intel_idle, which can mark the TSC as unstable.
......@@ -385,8 +390,6 @@ void sched_clock_tick(void)
void sched_clock_tick_stable(void)
{
u64 gtod, clock;
if (!sched_clock_stable())
return;
......@@ -398,9 +401,7 @@ void sched_clock_tick_stable(void)
* TSC to be unstable, any computation will be computing crap.
*/
local_irq_disable();
gtod = ktime_get_ns();
clock = sched_clock();
__gtod_offset = (clock + __sched_clock_offset) - gtod;
__sched_clock_gtod_offset();
local_irq_enable();
}
......@@ -434,6 +435,12 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
void __init sched_clock_init(void)
{
sched_clock_running = 1;
generic_sched_clock_init();
}
u64 sched_clock_cpu(int cpu)
{
if (unlikely(!sched_clock_running))
......
......@@ -5954,7 +5954,6 @@ void __init sched_init(void)
int i, j;
unsigned long alloc_size = 0, ptr;
sched_clock_init();
wait_bit_init();
#ifdef CONFIG_FAIR_GROUP_SCHED
......
......@@ -237,7 +237,7 @@ sched_clock_register(u64 (*read)(void), int bits, unsigned long rate)
pr_debug("Registered %pF as sched_clock source\n", read);
}
void __init sched_clock_postinit(void)
void __init generic_sched_clock_init(void)
{
/*
* If no sched_clock() function has been provided at that point,
......
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