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Commit 8c215bd3 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Cure nr_iowait_cpu() users 



Commit 0224cf4c (sched: Intoduce get_cpu_iowait_time_us())
broke things by not making sure preemption was indeed disabled
by the callers of nr_iowait_cpu() which took the iowait value of
the current cpu.

This resulted in a heap of preempt warnings. Cure this by making
nr_iowait_cpu() take a cpu number and fix up the callers to pass
in the right number.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-pm@lists.linux-foundation.org
LKML-Reference: <1277968037.1868.120.camel@laptop>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 97158569

drivers/cpuidle/governors/menu.c

+2 −2
Original line number Diff line number Diff line
@@ -143,7 +143,7 @@ static inline int which_bucket(unsigned int duration) 
	 * This allows us to calculate

	 * E(duration)|iowait

	 */

	if (nr_iowait_cpu())

	if (nr_iowait_cpu(smp_processor_id()))

		bucket = BUCKETS/2;



	if (duration < 10)
@@ -175,7 +175,7 @@ static inline int performance_multiplier(void) 
	mult += 2 * get_loadavg();



	/* for IO wait tasks (per cpu!) we add 5x each */

	mult += 10 * nr_iowait_cpu();

	mult += 10 * nr_iowait_cpu(smp_processor_id());



	return mult;

}

include/linux/sched.h

+1 −1
Original line number Diff line number Diff line
@@ -139,7 +139,7 @@ extern int nr_processes(void); 
extern unsigned long nr_running(void);

extern unsigned long nr_uninterruptible(void);

extern unsigned long nr_iowait(void);

extern unsigned long nr_iowait_cpu(void);

extern unsigned long nr_iowait_cpu(int cpu);

extern unsigned long this_cpu_load(void);

kernel/sched.c

+2 −2
Original line number Diff line number Diff line
@@ -2864,9 +2864,9 @@ unsigned long nr_iowait(void) 
	return sum;

}



unsigned long nr_iowait_cpu(void)

unsigned long nr_iowait_cpu(int cpu)

{

	struct rq *this = this_rq();

	struct rq *this = cpu_rq(cpu);

	return atomic_read(&this->nr_iowait);

}

kernel/time/tick-sched.c

+8 −8
Original line number Diff line number Diff line
@@ -154,14 +154,14 @@ static void tick_nohz_update_jiffies(ktime_t now) 
 * Updates the per cpu time idle statistics counters

 */

static void

update_ts_time_stats(struct tick_sched *ts, ktime_t now, u64 *last_update_time)

update_ts_time_stats(int cpu, struct tick_sched *ts, ktime_t now, u64 *last_update_time)

{

	ktime_t delta;



	if (ts->idle_active) {

		delta = ktime_sub(now, ts->idle_entrytime);

		ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);

		if (nr_iowait_cpu() > 0)

		if (nr_iowait_cpu(cpu) > 0)

			ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta);

		ts->idle_entrytime = now;

	}
@@ -175,19 +175,19 @@ static void tick_nohz_stop_idle(int cpu, ktime_t now) 
{

	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);



	update_ts_time_stats(ts, now, NULL);

	update_ts_time_stats(cpu, ts, now, NULL);

	ts->idle_active = 0;



	sched_clock_idle_wakeup_event(0);

}



static ktime_t tick_nohz_start_idle(struct tick_sched *ts)

static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts)

{

	ktime_t now;



	now = ktime_get();



	update_ts_time_stats(ts, now, NULL);

	update_ts_time_stats(cpu, ts, now, NULL);



	ts->idle_entrytime = now;

	ts->idle_active = 1;
@@ -216,7 +216,7 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time) 
	if (!tick_nohz_enabled)

		return -1;



	update_ts_time_stats(ts, ktime_get(), last_update_time);

	update_ts_time_stats(cpu, ts, ktime_get(), last_update_time);



	return ktime_to_us(ts->idle_sleeptime);

}
@@ -242,7 +242,7 @@ u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time) 
	if (!tick_nohz_enabled)

		return -1;



	update_ts_time_stats(ts, ktime_get(), last_update_time);

	update_ts_time_stats(cpu, ts, ktime_get(), last_update_time);



	return ktime_to_us(ts->iowait_sleeptime);

}
@@ -284,7 +284,7 @@ void tick_nohz_stop_sched_tick(int inidle) 
	 */

	ts->inidle = 1;



	now = tick_nohz_start_idle(ts);

	now = tick_nohz_start_idle(cpu, ts);



	/*

	 * If this cpu is offline and it is the one which updates