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Commit 807e5b80 authored by Wanpeng Li's avatar Wanpeng Li Committed by Ingo Molnar
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sched/cputime: Add steal time support to full dynticks CPU time accounting 



This patch adds guest steal-time support to full dynticks CPU
time accounting. After the following commit:

ff9a9b4c ("sched, time: Switch VIRT_CPU_ACCOUNTING_GEN to jiffy granularity")

... time sampling became jiffy based, even if we do the sampling from the
context tracking code, so steal_account_process_tick() can be reused
to account how many 'ticks' are stolen-time, after the last accumulation.

Signed-off-by: default avatarWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1465813966-3116-4-git-send-email-wanpeng.li@hotmail.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 3d89e547

kernel/sched/cputime.c

+9 −7
Original line number Diff line number Diff line
@@ -257,7 +257,7 @@ void account_idle_time(cputime_t cputime) 
		cpustat[CPUTIME_IDLE] += (__force u64) cputime;

}



static __always_inline bool steal_account_process_tick(void)

static __always_inline unsigned long steal_account_process_tick(unsigned long max_jiffies)

{

#ifdef CONFIG_PARAVIRT

	if (static_key_false(&paravirt_steal_enabled)) {
@@ -272,14 +272,14 @@ static __always_inline bool steal_account_process_tick(void) 
		 * time in jiffies. Lets cast the result to jiffies

		 * granularity and account the rest on the next rounds.

		 */

		steal_jiffies = nsecs_to_jiffies(steal);

		steal_jiffies = min(nsecs_to_jiffies(steal), max_jiffies);

		this_rq()->prev_steal_time += jiffies_to_nsecs(steal_jiffies);



		account_steal_time(jiffies_to_cputime(steal_jiffies));

		return steal_jiffies;

	}

#endif

	return false;

	return 0;

}



/*
@@ -346,7 +346,7 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick, 
	u64 cputime = (__force u64) cputime_one_jiffy;

	u64 *cpustat = kcpustat_this_cpu->cpustat;



	if (steal_account_process_tick())

	if (steal_account_process_tick(ULONG_MAX))

		return;



	cputime *= ticks;
@@ -477,7 +477,7 @@ void account_process_tick(struct task_struct *p, int user_tick) 
		return;

	}



	if (steal_account_process_tick())

	if (steal_account_process_tick(ULONG_MAX))

		return;



	if (user_tick)
@@ -681,12 +681,14 @@ static cputime_t vtime_delta(struct task_struct *tsk) 
static cputime_t get_vtime_delta(struct task_struct *tsk)

{

	unsigned long now = READ_ONCE(jiffies);

	unsigned long delta = now - tsk->vtime_snap;

	unsigned long delta_jiffies, steal_jiffies;



	delta_jiffies = now - tsk->vtime_snap;

	steal_jiffies = steal_account_process_tick(delta_jiffies);

	WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE);

	tsk->vtime_snap = now;



	return jiffies_to_cputime(delta);

	return jiffies_to_cputime(delta_jiffies - steal_jiffies);

}



static void __vtime_account_system(struct task_struct *tsk)