Commit dbc0fb35 authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
Browse files

s390/vtime: Fix virtual timer forwarding 



Since delayed accounting of system time [1] the virtual timer is
forwarded by do_account_vtime() but also vtime_account_kernel(),
vtime_account_softirq(), and vtime_account_hardirq(). This leads
to double accounting of system, guest, softirq, and hardirq time.

Remove accounting from the vtime_account*() family to restore old behavior.

There is only one user of the vtimer interface, which might explain
why nobody noticed this so far.

Fixes: b7394a5f ("sched/cputime, s390: Implement delayed accounting of system time") [1]
Reviewed-by: default avatarSven Schnelle <svens@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 0d785e2c

arch/s390/kernel/vtime.c

+2 −16
Original line number Diff line number Diff line
@@ -225,10 +225,6 @@ static u64 vtime_delta(void) 
	return timer - lc->last_update_timer;

}



/*

 * Update process times based on virtual cpu times stored by entry.S

 * to the lowcore fields user_timer, system_timer & steal_clock.

 */

void vtime_account_kernel(struct task_struct *tsk)

{

	struct lowcore *lc = get_lowcore();
@@ -238,27 +234,17 @@ void vtime_account_kernel(struct task_struct *tsk) 
		lc->guest_timer += delta;

	else

		lc->system_timer += delta;



	virt_timer_forward(delta);

}

EXPORT_SYMBOL_GPL(vtime_account_kernel);



void vtime_account_softirq(struct task_struct *tsk)

{

	u64 delta = vtime_delta();



	get_lowcore()->softirq_timer += delta;



	virt_timer_forward(delta);

	get_lowcore()->softirq_timer += vtime_delta();

}



void vtime_account_hardirq(struct task_struct *tsk)

{

	u64 delta = vtime_delta();



	get_lowcore()->hardirq_timer += delta;



	virt_timer_forward(delta);

	get_lowcore()->hardirq_timer += vtime_delta();

}



/*