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Commit 7eb43a6d authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86: Use generic idle thread allocation 



Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20120420124557.246929343@linutronix.de
parent 5cdaf183

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -82,6 +82,7 @@ config X86 
	select ARCH_HAVE_NMI_SAFE_CMPXCHG

	select GENERIC_IOMAP

	select DCACHE_WORD_ACCESS if !DEBUG_PAGEALLOC

	select GENERIC_SMP_IDLE_THREAD



config INSTRUCTION_DECODER

	def_bool (KPROBES || PERF_EVENTS)

arch/x86/include/asm/smp.h

+1 −0
Original line number Diff line number Diff line
@@ -164,6 +164,7 @@ int wbinvd_on_all_cpus(void); 


void native_send_call_func_ipi(const struct cpumask *mask);

void native_send_call_func_single_ipi(int cpu);

void x86_idle_thread_init(unsigned int cpu, struct task_struct *idle);



void smp_store_cpu_info(int id);

#define cpu_physical_id(cpu)	per_cpu(x86_cpu_to_apicid, cpu)

arch/x86/kernel/smpboot.c

+10 −71
Original line number Diff line number Diff line
@@ -76,19 +76,7 @@ 
/* 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))



/*

 * We need this for trampoline_base protection from concurrent accesses when

 * off- and onlining cores wildly.
@@ -107,10 +95,6 @@ void cpu_hotplug_driver_unlock(void) 


ssize_t arch_cpu_probe(const char *buf, size_t count) { return -1; }

ssize_t arch_cpu_release(const char *buf, size_t count) { return -1; }

#else

static 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



/* Number of siblings per CPU package */
@@ -618,22 +602,6 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip) 
	return (send_status | accept_status);

}



struct create_idle {

	struct work_struct work;

	struct task_struct *idle;

	struct completion done;

	int cpu;

};



static void __cpuinit do_fork_idle(struct work_struct *work)

{

	struct create_idle *c_idle =

		container_of(work, struct create_idle, work);



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

	complete(&c_idle->done);

}



/* reduce the number of lines printed when booting a large cpu count system */

static void __cpuinit announce_cpu(int cpu, int apicid)

{
@@ -660,58 +628,31 @@ static void __cpuinit announce_cpu(int cpu, int apicid) 
 * Returns zero if CPU booted OK, else error code from

 * ->wakeup_secondary_cpu.

 */

static int __cpuinit do_boot_cpu(int apicid, int cpu)

static int __cpuinit do_boot_cpu(int apicid, int cpu, struct task_struct *idle)

{

	unsigned long boot_error = 0;

	unsigned long start_ip;

	int timeout;

	struct create_idle c_idle = {

		.cpu	= cpu,

		.done	= COMPLETION_INITIALIZER_ONSTACK(c_idle.done),

	};



	INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);



	alternatives_smp_switch(1);



	c_idle.idle = get_idle_for_cpu(cpu);



	/*

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

	 * reschedule the child.

	 */

	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;

	}



	schedule_work(&c_idle.work);

	wait_for_completion(&c_idle.done);

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

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

	per_cpu(current_task, cpu) = idle;



	if (IS_ERR(c_idle.idle)) {

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

		destroy_work_on_stack(&c_idle.work);

		return PTR_ERR(c_idle.idle);

	}



	set_idle_for_cpu(cpu, c_idle.idle);

do_rest:

	per_cpu(current_task, cpu) = c_idle.idle;

#ifdef CONFIG_X86_32

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

	irq_ctx_init(cpu);

#else

	clear_tsk_thread_flag(c_idle.idle, TIF_FORK);

	clear_tsk_thread_flag(idle, TIF_FORK);

	initial_gs = per_cpu_offset(cpu);

	per_cpu(kernel_stack, cpu) =

		(unsigned long)task_stack_page(c_idle.idle) -

		(unsigned long)task_stack_page(idle) -

		KERNEL_STACK_OFFSET + THREAD_SIZE;

#endif

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

	initial_code = (unsigned long)start_secondary;

	stack_start  = c_idle.idle->thread.sp;

	stack_start  = idle->thread.sp;



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

	start_ip = trampoline_address();
@@ -813,8 +754,6 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu) 
		 */

		smpboot_restore_warm_reset_vector();

	}



	destroy_work_on_stack(&c_idle.work);

	return boot_error;

}
@@ -851,7 +790,7 @@ int __cpuinit native_cpu_up(unsigned int cpu, struct task_struct *tidle) 


	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;



	err = do_boot_cpu(apicid, cpu);

	err = do_boot_cpu(apicid, cpu, tidle);

	if (err) {

		pr_debug("do_boot_cpu failed %d\n", err);

		return -EIO;

arch/x86/xen/smp.c

+2 −13
Original line number Diff line number Diff line
@@ -250,19 +250,9 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus) 
		set_cpu_possible(cpu, false);

	}



	for_each_possible_cpu (cpu) {

		struct task_struct *idle;



		if (cpu == 0)

			continue;



		idle = fork_idle(cpu);

		if (IS_ERR(idle))

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



	for_each_possible_cpu(cpu)

		set_cpu_present(cpu, true);

}

}



static int __cpuinit

cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
@@ -331,9 +321,8 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle) 
	return 0;

}



static int __cpuinit xen_cpu_up(unsigned int cpu, struct task_struct *tidle)

static int __cpuinit xen_cpu_up(unsigned int cpu, struct task_struct *idle)

{

	struct task_struct *idle = idle_task(cpu);

	int rc;



	per_cpu(current_task, cpu) = idle;