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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2016-12-20 07:27:59 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2016-12-20 15:22:56 +0100 |
| commit | 8f2b468aadc81ca0fc78e41696b648e30d91ba5c (patch) | |
| tree | 6908c5d1c11e29847a371567ed5ec09d08707bd4 /arch/s390/kernel | |
| parent | e93b1cc8a8965da137ffea0b88e5f62fa1d2a9e6 (diff) | |
| download | linux-8f2b468aadc81ca0fc78e41696b648e30d91ba5c.tar.gz linux-8f2b468aadc81ca0fc78e41696b648e30d91ba5c.tar.xz | |
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>
Diffstat (limited to 'arch/s390/kernel')
| -rw-r--r-- | arch/s390/kernel/vtime.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c index 6b246aadf311..1b5c5ee9fc1b 100644 --- a/arch/s390/kernel/vtime.c +++ b/arch/s390/kernel/vtime.c @@ -94,7 +94,7 @@ static void update_mt_scaling(void) * Update process times based on virtual cpu times stored by entry.S * to the lowcore fields user_timer, system_timer & steal_clock. */ -static int do_account_vtime(struct task_struct *tsk, int hardirq_offset) +static int do_account_vtime(struct task_struct *tsk) { u64 timer, clock, user, system, steal; u64 user_scaled, system_scaled; @@ -138,7 +138,7 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset) } account_user_time(tsk, user); tsk->utimescaled += user_scaled; - account_system_time(tsk, hardirq_offset, system); + account_system_time(tsk, 0, system); tsk->stimescaled += system_scaled; steal = S390_lowcore.steal_timer; @@ -152,7 +152,7 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset) void vtime_task_switch(struct task_struct *prev) { - do_account_vtime(prev, 0); + do_account_vtime(prev); prev->thread.user_timer = S390_lowcore.user_timer; prev->thread.system_timer = S390_lowcore.system_timer; S390_lowcore.user_timer = current->thread.user_timer; @@ -166,7 +166,7 @@ void vtime_task_switch(struct task_struct *prev) */ void vtime_account_user(struct task_struct *tsk) { - if (do_account_vtime(tsk, HARDIRQ_OFFSET)) + if (do_account_vtime(tsk)) virt_timer_expire(); } |