Commit 9778385d authored Nov 15, 2007 by Christian Borntraeger Committed by Ingo Molnar Nov 15, 2007

sched: fix accounting of interrupts during guest execution on s390



Currently the scheduler checks for PF_VCPU to decide if this timeslice
has to be accounted as guest time. On s390 host interrupts are not
disabled during guest execution. This causes theses interrupts to be
accounted as guest time if CONFIG_VIRT_CPU_ACCOUNTING is set. Solution
is to check if an interrupt triggered account_system_time. As the tick
is timer interrupt based, we have to subtract hardirq_offset.

I tested the patch on s390 with CONFIG_VIRT_CPU_ACCOUNTING and on
x86_64. Seems to work.

CC: Avi Kivity <avi@qumranet.com>
CC: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 99fee6d7

kernel/sched.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -3390,10 +3390,8 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
		struct rq *rq = this_rq();
		cputime64_t tmp;

		if (p->flags & PF_VCPU) {
		account_guest_time(p, cputime);
		return;
		}
		if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0))
		return account_guest_time(p, cputime);

		p->stime = cputime_add(p->stime, cputime);

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