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Commit da7f51c1 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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[S390] smp/idle: call init_idle() before starting a new cpu 



Call init_idle() which (re-)initializes the idle task structure before
it gets used on a new cpu.
That way we can also get rid of the odd preempt_enable_no_resched()
call we have in the cpu offline path within cpu_idle(). That call
prevented preempt count imbalances between cpu hotplug operations.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent f230886b

arch/s390/include/asm/smp.h

+2 −1
Original line number Diff line number Diff line
@@ -20,7 +20,6 @@ extern void machine_power_off_smp(void); 


extern int __cpu_disable (void);

extern void __cpu_die (unsigned int cpu);

extern void cpu_die (void) __attribute__ ((noreturn));

extern int __cpu_up (unsigned int cpu);



extern struct mutex smp_cpu_state_mutex;
@@ -71,8 +70,10 @@ static inline void smp_switch_to_ipl_cpu(void (*func)(void *), void *data) 


#ifdef CONFIG_HOTPLUG_CPU

extern int smp_rescan_cpus(void);

extern void __noreturn cpu_die(void);

#else

static inline int smp_rescan_cpus(void) { return 0; }

static inline void cpu_die(void) { }

#endif



#endif /* __ASM_SMP_H */

arch/s390/kernel/process.c

+2 −6
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#include <asm/irq.h>

#include <asm/timer.h>

#include <asm/nmi.h>

#include <asm/smp.h>

#include "entry.h"



asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
@@ -76,13 +77,8 @@ unsigned long thread_saved_pc(struct task_struct *tsk) 
 */

static void default_idle(void)

{

	/* CPU is going idle. */

#ifdef CONFIG_HOTPLUG_CPU

	if (cpu_is_offline(smp_processor_id())) {

		preempt_enable_no_resched();

	if (cpu_is_offline(smp_processor_id()))

		cpu_die();

	}

#endif

	local_irq_disable();

	if (need_resched()) {

		local_irq_enable();

arch/s390/kernel/smp.c

+1 −0
Original line number Diff line number Diff line
@@ -575,6 +575,7 @@ int __cpuinit __cpu_up(unsigned int cpu) 
		idle = c_idle.idle;

		current_set[cpu] = c_idle.idle;

	}

	init_idle(idle, cpu);

	if (smp_alloc_lowcore(cpu))

		return -ENOMEM;

	do {