Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 032014bc authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Martin Schwidefsky
Browse files

s390/vtime: Get rid of redundant WARN_ON 



in the cpu time accounting function vtime_account_irq_enter
(vtime_account_system) we use a WARN_ON_ONCE(!irqs_disabled()).
This is redundant as the function virt_timer_forward is always
called and has a BUG_ON(!irqs_disabled()).

This saves several nanoseconds in my specific testcase (KVM entry/exit)
and probably all other callers like (soft)irq entry/exit.

Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 099eae11

arch/s390/kernel/vtime.c

+0 −2
Original line number Diff line number Diff line
@@ -128,8 +128,6 @@ void vtime_account_irq_enter(struct task_struct *tsk) 
	struct thread_info *ti = task_thread_info(tsk);

	u64 timer, system;



	WARN_ON_ONCE(!irqs_disabled());



	timer = S390_lowcore.last_update_timer;

	S390_lowcore.last_update_timer = get_vtimer();

	S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;