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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2010-05-17 12:00:03 +0400 |
|---|---|---|
| committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2010-05-17 12:00:15 +0400 |
| commit | 6377981faf1a4425b0531e577736ef03df97c8f6 (patch) | |
| tree | f690c5d357413cb6f26c8463519ad2b1f8800851 /arch/s390/include/asm/cputime.h | |
| parent | 6a2df3a87276cdc08fd87070d09ea18d1fb9d622 (diff) | |
| download | linux-6377981faf1a4425b0531e577736ef03df97c8f6.tar.xz | |
[S390] idle time accounting vs. machine checks
A machine check can interrupt the i/o and external interrupt handler
anytime. If the machine check occurs while the interrupt handler is
waking up from idle vtime_start_cpu can get executed a second time
and the int_clock / async_enter_timer values in the lowcore get
clobbered. This can confuse the cpu time accounting.
To fix this problem two changes are needed. First the machine check
handler has to use its own copies of int_clock and async_enter_timer,
named mcck_clock and mcck_enter_timer. Second the nested execution
of vtime_start_cpu has to be prevented. This is done in s390_idle_check
by checking the wait bit in the program status word.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/cputime.h')
| -rw-r--r-- | arch/s390/include/asm/cputime.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h index 258ba88b7b50..8b1a52a137c5 100644 --- a/arch/s390/include/asm/cputime.h +++ b/arch/s390/include/asm/cputime.h @@ -188,15 +188,16 @@ struct s390_idle_data { DECLARE_PER_CPU(struct s390_idle_data, s390_idle); -void vtime_start_cpu(void); +void vtime_start_cpu(__u64 int_clock, __u64 enter_timer); cputime64_t s390_get_idle_time(int cpu); #define arch_idle_time(cpu) s390_get_idle_time(cpu) -static inline void s390_idle_check(void) +static inline void s390_idle_check(struct pt_regs *regs, __u64 int_clock, + __u64 enter_timer) { - if ((&__get_cpu_var(s390_idle))->idle_enter != 0ULL) - vtime_start_cpu(); + if (regs->psw.mask & PSW_MASK_WAIT) + vtime_start_cpu(int_clock, enter_timer); } static inline int s390_nohz_delay(int cpu) |