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Commit fe0f4976 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

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



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: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent a9b16499

arch/s390/include/asm/cputime.h

+0 −8
Original line number Original line Diff line number Diff line
@@ -166,7 +166,6 @@ static inline clock_t cputime64_to_clock_t(cputime64_t cputime) 
}

}





struct s390_idle_data {

struct s390_idle_data {

	int nohz_delay;

	unsigned int sequence;

	unsigned int sequence;

	unsigned long long idle_count;

	unsigned long long idle_count;

	unsigned long long idle_time;

	unsigned long long idle_time;
@@ -182,11 +181,4 @@ cputime64_t s390_get_idle_time(int cpu); 




#define arch_idle_time(cpu) s390_get_idle_time(cpu)

#define arch_idle_time(cpu) s390_get_idle_time(cpu)





static inline int s390_nohz_delay(int cpu)

{

	return __get_cpu_var(s390_idle).nohz_delay != 0;

}



#define arch_needs_cpu(cpu) s390_nohz_delay(cpu)



#endif /* _S390_CPUTIME_H */
 
#endif /* _S390_CPUTIME_H */

arch/s390/include/asm/processor.h

+4 −0
Original line number Original line Diff line number Diff line
@@ -13,9 +13,11 @@ 




#define CIF_MCCK_PENDING	0	/* machine check handling is pending */

#define CIF_MCCK_PENDING	0	/* machine check handling is pending */

#define CIF_ASCE		1	/* user asce needs fixup / uaccess */

#define CIF_ASCE		1	/* user asce needs fixup / uaccess */

#define CIF_NOHZ_DELAY		2	/* delay HZ disable for a tick */





#define _CIF_MCCK_PENDING	(1<<CIF_MCCK_PENDING)

#define _CIF_MCCK_PENDING	(1<<CIF_MCCK_PENDING)

#define _CIF_ASCE		(1<<CIF_ASCE)

#define _CIF_ASCE		(1<<CIF_ASCE)

#define _CIF_NOHZ_DELAY		(1<<CIF_NOHZ_DELAY)









#ifndef __ASSEMBLY__

#ifndef __ASSEMBLY__
@@ -43,6 +45,8 @@ static inline int test_cpu_flag(int flag) 
	return !!(S390_lowcore.cpu_flags & (1U << flag));

	return !!(S390_lowcore.cpu_flags & (1U << flag));

}

}





#define arch_needs_cpu() test_cpu_flag(CIF_NOHZ_DELAY)



/*

/*

 * Default implementation of macro that returns current

 * Default implementation of macro that returns current

 * instruction pointer ("program counter").

 * instruction pointer ("program counter").

arch/s390/kernel/irq.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -259,7 +259,7 @@ static irqreturn_t do_ext_interrupt(int irq, void *dummy) 




	ext_code = *(struct ext_code *) &regs->int_code;

	ext_code = *(struct ext_code *) &regs->int_code;

	if (ext_code.code != EXT_IRQ_CLK_COMP)

	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);

	index = ext_hash(ext_code.code);

	rcu_read_lock();

	rcu_read_lock();

arch/s390/kernel/smp.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -720,6 +720,7 @@ int __cpu_disable(void) 
	cregs[6]  &= ~0xff000000UL;	/* disable all I/O interrupts */

	cregs[6]  &= ~0xff000000UL;	/* disable all I/O interrupts */

	cregs[14] &= ~0x1f000000UL;	/* disable most machine checks */

	cregs[14] &= ~0x1f000000UL;	/* disable most machine checks */

	__ctl_load(cregs, 0, 15);

	__ctl_load(cregs, 0, 15);

	clear_cpu_flag(CIF_NOHZ_DELAY);

	return 0;

	return 0;

}

}

arch/s390/kernel/vtime.c

+1 −18
Original line number Original line Diff line number Diff line
@@ -163,7 +163,7 @@ void __kprobes vtime_stop_cpu(void) 
	/* Wait for external, I/O or machine check interrupt. */

	/* Wait for external, I/O or machine check interrupt. */

	psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT |

	psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT |

		PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;

		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 */

	/* Call the assembler magic in entry.S */

	psw_idle(idle, psw_mask);

	psw_idle(idle, psw_mask);
@@ -378,25 +378,8 @@ void init_cpu_vtimer(void) 
	set_vtimer(VTIMER_MAX_SLICE);

	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)

void __init vtime_init(void)

{

{

	/* Enable cpu timer interrupts on the boot cpu. */

	/* Enable cpu timer interrupts on the boot cpu. */

	init_cpu_vtimer();

	init_cpu_vtimer();

	cpu_notifier(s390_nohz_notify, 0);

}
 
}