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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: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2011-01-05 12:48:09 +01:00 committed by Martin Schwidefsky
parent f230886b0b
commit da7f51c11d
3 changed files with 5 additions and 7 deletions
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3
arch/s390/include/asm/smp.h
View File

@ -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 */

8
arch/s390/kernel/process.c
View File

@ -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();

1
arch/s390/kernel/smp.c
View File

@ -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 {