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nohz: Separate idle sleeping time accounting from nohz logic

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As we plan to be able to stop the tick outside the idle task, we
need to prepare for separating nohz logic from idle. As a start,
this pulls the idle sleeping time accounting out of the tick
stop/restart API to the callers on idle entry/exit.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Frederic Weisbecker 2011-07-27 17:29:28 +02:00
parent cfaf025112
commit 19f5f7364a
1 changed files with 42 additions and 35 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

77
kernel/time/tick-sched.c
View file

@ -271,10 +271,10 @@ u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time)
} }
EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us); EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us);
static void tick_nohz_stop_sched_tick(struct tick_sched *ts) static void tick_nohz_stop_sched_tick(struct tick_sched *ts, ktime_t now)
{ {
unsigned long seq, last_jiffies, next_jiffies, delta_jiffies; unsigned long seq, last_jiffies, next_jiffies, delta_jiffies;
ktime_t last_update, expires, now; ktime_t last_update, expires;
struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev; struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
u64 time_delta; u64 time_delta;
int cpu; int cpu;
@ -282,8 +282,6 @@ static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
cpu = smp_processor_id(); cpu = smp_processor_id();
ts = &per_cpu(tick_cpu_sched, cpu); ts = &per_cpu(tick_cpu_sched, cpu);
now = tick_nohz_start_idle(cpu, ts);
/* /*
* If this cpu is offline and it is the one which updates * If this cpu is offline and it is the one which updates
* jiffies, then give up the assignment and let it be taken by * jiffies, then give up the assignment and let it be taken by
@ -444,6 +442,14 @@ static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
ts->sleep_length = ktime_sub(dev->next_event, now); ts->sleep_length = ktime_sub(dev->next_event, now);
} }
static void __tick_nohz_idle_enter(struct tick_sched *ts)
{
ktime_t now;
now = tick_nohz_start_idle(smp_processor_id(), ts);
tick_nohz_stop_sched_tick(ts, now);
}
/** /**
* tick_nohz_idle_enter - stop the idle tick from the idle task * tick_nohz_idle_enter - stop the idle tick from the idle task
* *
@ -479,7 +485,7 @@ void tick_nohz_idle_enter(void)
* update of the idle time accounting in tick_nohz_start_idle(). * update of the idle time accounting in tick_nohz_start_idle().
*/ */
ts->inidle = 1; ts->inidle = 1;
tick_nohz_stop_sched_tick(ts); __tick_nohz_idle_enter(ts);
local_irq_enable(); local_irq_enable();
} }
@ -499,7 +505,7 @@ void tick_nohz_irq_exit(void)
if (!ts->inidle) if (!ts->inidle)
return; return;
tick_nohz_stop_sched_tick(ts); __tick_nohz_idle_enter(ts);
} }
/** /**
@ -540,39 +546,11 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
} }
} }
/** static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
* tick_nohz_idle_exit - restart the idle tick from the idle task
*
* Restart the idle tick when the CPU is woken up from idle
* This also exit the RCU extended quiescent state. The CPU
* can use RCU again after this function is called.
*/
void tick_nohz_idle_exit(void)
{ {
int cpu = smp_processor_id();
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
#ifndef CONFIG_VIRT_CPU_ACCOUNTING #ifndef CONFIG_VIRT_CPU_ACCOUNTING
unsigned long ticks; unsigned long ticks;
#endif #endif
ktime_t now;
local_irq_disable();
WARN_ON_ONCE(!ts->inidle);
ts->inidle = 0;
if (ts->idle_active || ts->tick_stopped)
now = ktime_get();
if (ts->idle_active)
tick_nohz_stop_idle(cpu, now);
if (!ts->tick_stopped) {
local_irq_enable();
return;
}
/* Update jiffies first */ /* Update jiffies first */
select_nohz_load_balancer(0); select_nohz_load_balancer(0);
tick_do_update_jiffies64(now); tick_do_update_jiffies64(now);
@ -600,6 +578,35 @@ void tick_nohz_idle_exit(void)
ts->idle_exittime = now; ts->idle_exittime = now;
tick_nohz_restart(ts, now); tick_nohz_restart(ts, now);
}
/**
* tick_nohz_idle_exit - restart the idle tick from the idle task
*
* Restart the idle tick when the CPU is woken up from idle
* This also exit the RCU extended quiescent state. The CPU
* can use RCU again after this function is called.
*/
void tick_nohz_idle_exit(void)
{
int cpu = smp_processor_id();
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
ktime_t now;
local_irq_disable();
WARN_ON_ONCE(!ts->inidle);
ts->inidle = 0;
if (ts->idle_active || ts->tick_stopped)
now = ktime_get();
if (ts->idle_active)
tick_nohz_stop_idle(cpu, now);
if (ts->tick_stopped)
tick_nohz_restart_sched_tick(ts, now);
local_irq_enable(); local_irq_enable();
} }