From 9778385db35a799d410039be123044a0d3e917a2 Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Thu, 15 Nov 2007 20:57:39 +0100
Subject: [PATCH] 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>
---
kernel/sched.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 4fb3532dd7e8..908335e1781a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -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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