From 4c1051e37a0e2a941115c6fb7ba08c318f25a0f9 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Sun, 11 Mar 2012 11:59:27 -0400 Subject: [S390] rework idle code 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 --- arch/s390/kernel/process.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'arch/s390/kernel/process.c') diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c index e795933eb2cb..78b3c149b8b6 100644 --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -77,13 +77,8 @@ static void default_idle(void) local_irq_enable(); return; } - trace_hardirqs_on(); - /* Don't trace preempt off for idle. */ - stop_critical_timings(); - /* Stop virtual timer and halt the cpu. */ + /* Halt the cpu and keep track of cpu time accounting. */ vtime_stop_cpu(); - /* Reenable preemption tracer. */ - start_critical_timings(); } void cpu_idle(void) -- cgit v1.2.3