s390/vtime: correct system time accounting
authorMartin Schwidefsky <schwidefsky@de.ibm.com>
Tue, 20 Dec 2016 06:27:59 +0000 (07:27 +0100)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Tue, 20 Dec 2016 14:22:56 +0000 (15:22 +0100)
commit8f2b468aadc81ca0fc78e41696b648e30d91ba5c
tree6908c5d1c11e29847a371567ed5ec09d08707bd4
parente93b1cc8a8965da137ffea0b88e5f62fa1d2a9e6
s390/vtime: correct system time accounting

There is a slight misaccounting of system time in vtime_account_user.
This function is called once per HZ tick in interrupt context.
The irq_enter function already accounted the system time up to the
point of the irq_enter call. The system time from irq_enter until
vtime_account_user/do_account_vtime is reached is irq time but it
is accounted to the previous context.

Just drop the hardirq offset from arch/s390/kernel/vtime.c.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/kernel/vtime.c