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[S390] rework idle code

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Whenever the cpu loads an enabled wait PSW it will appear as idle to the
underlying host system. The code in default_idle calls vtime_stop_cpu
which does the necessary voodoo to get the cpu time accounting right.
The udelay code just loads an enabled wait PSW. To correct this rework
the vtime_stop_cpu/vtime_start_cpu logic and move the difficult parts
to entry[64].S, vtime_stop_cpu can now be called from anywhere and
vtime_start_cpu is gone. The correction of the cpu time during wakeup
from an enabled wait PSW is done with a critical section in entry[64].S.
As vtime_start_cpu is gone, s390_idle_check can be removed as well.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2012-03-11 11:59:27 -04:00
parent 8b646bd759
commit 4c1051e37a
13 changed files with 214 additions and 214 deletions
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9
arch/s390/include/asm/cputime.h
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@@ -170,24 +170,17 @@ struct s390_idle_data {
unsigned int sequence;
unsigned long long idle_count;
unsigned long long idle_enter;
unsigned long long idle_exit;
unsigned long long idle_time;
int nohz_delay;
};
DECLARE_PER_CPU(struct s390_idle_data, s390_idle);
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(struct pt_regs *regs, __u64 int_clock,
__u64 enter_timer)
{
if (regs->psw.mask & PSW_MASK_WAIT)
vtime_start_cpu(int_clock, enter_timer);
}
static inline int s390_nohz_delay(int cpu)
{
return __get_cpu_var(s390_idle).nohz_delay != 0;