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s390/nohz: use a per-cpu flag for arch_needs_cpu

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Move the nohz_delay bit from the s390_idle data structure to the
per-cpu flags. Clear the nohz delay flag in __cpu_disable and
remove the cpu hotplug notifier that used to do this.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2014-09-30 17:37:52 +02:00
parent a9b1649917
commit fe0f49768d
9 changed files with 11 additions and 31 deletions
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2
arch/s390/kernel/irq.c
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@@ -259,7 +259,7 @@ static irqreturn_t do_ext_interrupt(int irq, void *dummy)
ext_code = *(struct ext_code *) &regs->int_code;
if (ext_code.code != EXT_IRQ_CLK_COMP)
__get_cpu_var(s390_idle).nohz_delay = 1;
set_cpu_flag(CIF_NOHZ_DELAY);
index = ext_hash(ext_code.code);
rcu_read_lock();

1
arch/s390/kernel/smp.c
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@@ -720,6 +720,7 @@ int __cpu_disable(void)
cregs[6] &= ~0xff000000UL; /* disable all I/O interrupts */
cregs[14] &= ~0x1f000000UL; /* disable most machine checks */
__ctl_load(cregs, 0, 15);
clear_cpu_flag(CIF_NOHZ_DELAY);
return 0;
}

19
arch/s390/kernel/vtime.c
View File

@@ -163,7 +163,7 @@ void __kprobes vtime_stop_cpu(void)
/* Wait for external, I/O or machine check interrupt. */
psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT |
PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
idle->nohz_delay = 0;
clear_cpu_flag(CIF_NOHZ_DELAY);
/* Call the assembler magic in entry.S */
psw_idle(idle, psw_mask);
@@ -378,25 +378,8 @@ void init_cpu_vtimer(void)
set_vtimer(VTIMER_MAX_SLICE);
}
static int s390_nohz_notify(struct notifier_block *self, unsigned long action,
void *hcpu)
{
struct s390_idle_data *idle;
long cpu = (long) hcpu;
idle = &per_cpu(s390_idle, cpu);
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DYING:
idle->nohz_delay = 0;
default:
break;
}
return NOTIFY_OK;
}
void __init vtime_init(void)
{
/* Enable cpu timer interrupts on the boot cpu. */
init_cpu_vtimer();
cpu_notifier(s390_nohz_notify, 0);
}