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Commit 365c894c authored by Glauber de Oliveira Costa's avatar Glauber de Oliveira Costa Committed by Ingo Molnar
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x86: use create_idle struct in do_boot_cpu 



Use a new worker, with help of the create_idle struct
to fork the idle thread. We now have two workers, the first
of them triggered by __smp_prepare_cpu. But the later is
going away soon.

Signed-off-by: default avatarGlauber Costa <gcosta@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ddd10ecf

arch/x86/kernel/smpboot_32.c

+59 −27
Original line number Diff line number Diff line
@@ -79,6 +79,24 @@ static void map_cpu_to_logical_apicid(void); 
/* State of each CPU. */

DEFINE_PER_CPU(int, cpu_state) = { 0 };



/* Store all idle threads, this can be reused instead of creating

* a new thread. Also avoids complicated thread destroy functionality

* for idle threads.

*/

#ifdef CONFIG_HOTPLUG_CPU

/*

 * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is

 * removed after init for !CONFIG_HOTPLUG_CPU.

 */

static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);

#define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))

#define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))

#else

struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;

#define get_idle_for_cpu(x)      (idle_thread_array[(x)])

#define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))

#endif



static atomic_t init_deasserted;



static void __cpuinit smp_callin(void)
@@ -513,30 +531,21 @@ wakeup_secondary_cpu(int phys_apicid, unsigned long start_eip) 


extern cpumask_t cpu_initialized;



#ifdef CONFIG_HOTPLUG_CPU

static struct task_struct * __cpuinitdata cpu_idle_tasks[NR_CPUS];

static inline struct task_struct * __cpuinit alloc_idle_task(int cpu)

{

struct create_idle {

	struct work_struct work;

	struct task_struct *idle;

	struct completion done;

	int cpu;

};



	if ((idle = cpu_idle_tasks[cpu]) != NULL) {

		/* initialize thread_struct.  we really want to avoid destroy

		 * idle tread

		 */

		idle->thread.sp = (unsigned long)task_pt_regs(idle);

		init_idle(idle, cpu);

		return idle;

	}

	idle = fork_idle(cpu);

static void __cpuinit do_fork_idle(struct work_struct *work)

{

	struct create_idle *c_idle =

		container_of(work, struct create_idle, work);



	if (!IS_ERR(idle))

		cpu_idle_tasks[cpu] = idle;

	return idle;

	c_idle->idle = fork_idle(c_idle->cpu);

	complete(&c_idle->done);

}

#else

#define alloc_idle_task(cpu) fork_idle(cpu)

#endif



static int __cpuinit do_boot_cpu(int apicid, int cpu)

/*

 * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
@@ -544,11 +553,15 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu) 
 * Returns zero if CPU booted OK, else error code from wakeup_secondary_cpu.

 */

{

	struct task_struct *idle;

	unsigned long boot_error;

	int timeout;

	unsigned long start_eip;

	unsigned short nmi_high = 0, nmi_low = 0;

	struct create_idle c_idle = {

		.cpu = cpu,

		.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),

	};

	INIT_WORK(&c_idle.work, do_fork_idle);



	/*

	 * Save current MTRR state in case it was changed since early boot
@@ -556,19 +569,38 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu) 
	 */

	mtrr_save_state();



	c_idle.idle = get_idle_for_cpu(cpu);



	/*

	 * We can't use kernel_thread since we must avoid to

	 * reschedule the child.

	 */

	idle = alloc_idle_task(cpu);

	if (IS_ERR(idle))

		panic("failed fork for CPU %d", cpu);

	if (c_idle.idle) {

		c_idle.idle->thread.sp = (unsigned long) (((struct pt_regs *)

			(THREAD_SIZE +  task_stack_page(c_idle.idle))) - 1);

		init_idle(c_idle.idle, cpu);

		goto do_rest;

	}



	if (!keventd_up() || current_is_keventd())

		c_idle.work.func(&c_idle.work);

	else {

		schedule_work(&c_idle.work);

		wait_for_completion(&c_idle.done);

	}



	if (IS_ERR(c_idle.idle)) {

		printk(KERN_ERR "failed fork for CPU %d\n", cpu);

		return PTR_ERR(c_idle.idle);

	}



	set_idle_for_cpu(cpu, c_idle.idle);

do_rest:

	per_cpu(current_task, cpu) = c_idle.idle;

	init_gdt(cpu);

 	per_cpu(current_task, cpu) = idle;

	early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);



	idle->thread.ip = (unsigned long) start_secondary;

	c_idle.idle->thread.ip = (unsigned long) start_secondary;

	/* start_eip had better be page-aligned! */

	start_eip = setup_trampoline();
@@ -577,7 +609,7 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu) 
	/* So we see what's up   */

	printk("Booting processor %d/%d ip %lx\n", cpu, apicid, start_eip);

	/* Stack for startup_32 can be just as for start_secondary onwards */

	stack_start.sp = (void *) idle->thread.sp;

	stack_start.sp = (void *) c_idle.idle->thread.sp;



	irq_ctx_init(cpu);