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Commit ea99d5c0 authored by Stephen Boyd's avatar Stephen Boyd Committed by Maulik Shah
Browse files

timers, sched/clock: Hook into s2idle freeze path 



The sched_clock() suspend/resume callbacks are called from a
syscore_ops structure that's registered after the timekeeping
syscore_ops. With the suspend-to-idle method of suspend we will
freeze the tick and timekeeping subsystem, but we don't suspend
the sched clock here, because syscore ops are not called in
suspend to idle. Hook this up directly in the timekeeping freeze
path when we go idle on the last CPU. This way, the sched clock
doesn't jump across a suspend/resume cycle.

Change-Id: I2ea488dce7186d6210d3af34b0e1a67c9f1cdf78
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
parent ed416589

include/linux/sched_clock.h

+4 −0
Original line number Diff line number Diff line
@@ -13,6 +13,8 @@ extern void generic_sched_clock_init(void); 


extern void sched_clock_register(u64 (*read)(void), int bits,

				 unsigned long rate);

extern int sched_clock_suspend(void);

extern void sched_clock_resume(void);

#else

static inline void generic_sched_clock_init(void) { }
@@ -20,6 +22,8 @@ static inline void sched_clock_register(u64 (*read)(void), int bits, 
					unsigned long rate)

{

}

static inline int sched_clock_suspend(void) { return 0; }

static inline void sched_clock_resume(void) { }

#endif



#endif

kernel/time/sched_clock.c

+2 −2
Original line number Diff line number Diff line
@@ -278,7 +278,7 @@ static u64 notrace suspended_sched_clock_read(void) 
	return cd.read_data[seq & 1].epoch_cyc;

}



static int sched_clock_suspend(void)

int sched_clock_suspend(void)

{

	struct clock_read_data *rd = &cd.read_data[0];
@@ -294,7 +294,7 @@ static int sched_clock_suspend(void) 
	return 0;

}



static void sched_clock_resume(void)

void sched_clock_resume(void)

{

	struct clock_read_data *rd = &cd.read_data[0];

kernel/time/tick-common.c

+3 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/percpu.h>

#include <linux/profile.h>

#include <linux/sched.h>

#include <linux/sched_clock.h>

#include <linux/module.h>

#include <trace/events/power.h>
@@ -491,6 +492,7 @@ void tick_freeze(void) 
		trace_suspend_resume(TPS("timekeeping_freeze"),

				     smp_processor_id(), true);

		system_state = SYSTEM_SUSPEND;

		sched_clock_suspend();

		timekeeping_suspend();

	} else {

		tick_suspend_local();
@@ -515,6 +517,7 @@ void tick_unfreeze(void) 
	if (tick_freeze_depth == num_online_cpus()) {

		timekeeping_resume();

		system_state = SYSTEM_RUNNING;

		sched_clock_resume();

		trace_suspend_resume(TPS("timekeeping_freeze"),

				     smp_processor_id(), false);

	} else {