C++ cpumask_clear_cpu函数代码示例

/*==========================================================================*
 * Name:         smp_flush_cache_all
 *
 * Description:  This routine sends a 'INVALIDATE_CACHE_IPI' to all other
 *               CPUs in the system.
 *
 * Born on Date: 2003-05-28
 *
 * Arguments:    NONE
 *
 * Returns:      void (cannot fail)
 *
 * Modification log:
 * Date       Who Description
 * ---------- --- --------------------------------------------------------
 *
 *==========================================================================*/
void smp_flush_cache_all(void)
{
	cpumask_t cpumask;
	unsigned long *mask;

	preempt_disable();
	cpumask_copy(&cpumask, cpu_online_mask);
	cpumask_clear_cpu(smp_processor_id(), &cpumask);
	spin_lock(&flushcache_lock);
	mask=cpumask_bits(&cpumask);
	atomic_set_mask(*mask, (atomic_t *)&flushcache_cpumask);
	send_IPI_mask(&cpumask, INVALIDATE_CACHE_IPI, 0);
	_flush_cache_copyback_all();
	while (flushcache_cpumask)
		mb();
	spin_unlock(&flushcache_lock);
	preempt_enable();
}

/*
 * Remove a CPU from broadcasting
 */
void tick_shutdown_broadcast(unsigned int *cpup)
{
	struct clock_event_device *bc;
	unsigned long flags;
	unsigned int cpu = *cpup;

	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);

	bc = tick_broadcast_device.evtdev;
	cpumask_clear_cpu(cpu, tick_get_broadcast_mask());

	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
		if (bc && cpumask_empty(tick_get_broadcast_mask()))
			clockevents_shutdown(bc);
	}

	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

asmlinkage
#endif
void smp_invalidate_interrupt(struct pt_regs *regs)
{
	unsigned int cpu;
	unsigned int sender;
	union smp_flush_state *f;

	cpu = smp_processor_id();
	/*
	 * orig_rax contains the negated interrupt vector.
	 * Use that to determine where the sender put the data.
	 */
	sender = ~regs->orig_ax - INVALIDATE_TLB_VECTOR_START;
	f = &flush_state[sender];

	if (!cpumask_test_cpu(cpu, to_cpumask(f->flush_cpumask)))
		goto out;
		/*
		 * This was a BUG() but until someone can quote me the
		 * line from the intel manual that guarantees an IPI to
		 * multiple CPUs is retried _only_ on the erroring CPUs
		 * its staying as a return
		 *
		 * BUG();
		 */

	if (f->flush_mm == percpu_read(cpu_tlbstate.active_mm)) {
		if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK) {
			if (f->flush_va == TLB_FLUSH_ALL)
				local_flush_tlb();
			else
				__flush_tlb_one(f->flush_va);
		} else
			leave_mm(cpu);
	}
out:
	ack_APIC_irq();
	smp_mb__before_clear_bit();
	cpumask_clear_cpu(cpu, to_cpumask(f->flush_cpumask));
	smp_mb__after_clear_bit();
	inc_irq_stat(irq_tlb_count);
}

/* Parse the boot-time nohz CPU list from the kernel parameters. */
static int __init tick_nohz_full_setup(char *str)
{
	int cpu;

	alloc_bootmem_cpumask_var(&nohz_full_mask);
	if (cpulist_parse(str, nohz_full_mask) < 0) {
		pr_warning("NOHZ: Incorrect nohz_full cpumask\n");
		return 1;
	}

	cpu = smp_processor_id();
	if (cpumask_test_cpu(cpu, nohz_full_mask)) {
		pr_warning("NO_HZ: Clearing %d from nohz_full range for timekeeping\n", cpu);
		cpumask_clear_cpu(cpu, nohz_full_mask);
	}
	have_nohz_full_mask = true;

	return 1;
}

/**
 * smp_cache_interrupt - Handle IPI request to flush caches.
 *
 * Handle a request delivered by IPI to flush the current CPU's
 * caches.  The parameters are stored in smp_cache_*.
 */
void smp_cache_interrupt(void)
{
	unsigned long opr_mask = smp_cache_mask;

	switch ((enum smp_dcache_ops)(opr_mask & SMP_DCACHE_OP_MASK)) {
	case SMP_DCACHE_NOP:
		break;
	case SMP_DCACHE_INV:
		mn10300_local_dcache_inv();
		break;
	case SMP_DCACHE_INV_RANGE:
		mn10300_local_dcache_inv_range(smp_cache_start, smp_cache_end);
		break;
	case SMP_DCACHE_FLUSH:
		mn10300_local_dcache_flush();
		break;
	case SMP_DCACHE_FLUSH_RANGE:
		mn10300_local_dcache_flush_range(smp_cache_start,
						 smp_cache_end);
		break;
	case SMP_DCACHE_FLUSH_INV:
		mn10300_local_dcache_flush_inv();
		break;
	case SMP_DCACHE_FLUSH_INV_RANGE:
		mn10300_local_dcache_flush_inv_range(smp_cache_start,
						     smp_cache_end);
		break;
	}

	switch ((enum smp_icache_ops)(opr_mask & SMP_ICACHE_OP_MASK)) {
	case SMP_ICACHE_NOP:
		break;
	case SMP_ICACHE_INV:
		mn10300_local_icache_inv();
		break;
	case SMP_ICACHE_INV_RANGE:
		mn10300_local_icache_inv_range(smp_cache_start, smp_cache_end);
		break;
	}

	cpumask_clear_cpu(smp_processor_id(), &smp_cache_ipi_map);
}

/*
 * Try to steal tags from a remote cpu's percpu freelist.
 *
 * We first check how many percpu freelists have tags - we don't steal tags
 * unless enough percpu freelists have tags on them that it's possible more than
 * half the total tags could be stuck on remote percpu freelists.
 *
 * Then we iterate through the cpus until we find some tags - we don't attempt
 * to find the "best" cpu to steal from, to keep cacheline bouncing to a
 * minimum.
 */
static inline void steal_tags(struct percpu_ida *pool,
			      struct percpu_ida_cpu *tags)
{
	unsigned cpus_have_tags, cpu = pool->cpu_last_stolen;
	struct percpu_ida_cpu *remote;

	for (cpus_have_tags = cpumask_weight(&pool->cpus_have_tags);
	     cpus_have_tags * IDA_PCPU_SIZE > pool->nr_tags / 2;
	     cpus_have_tags--) {
		cpu = cpumask_next(cpu, &pool->cpus_have_tags);

		if (cpu >= nr_cpu_ids) {
			cpu = cpumask_first(&pool->cpus_have_tags);
			if (cpu >= nr_cpu_ids)
				BUG();
		}

		pool->cpu_last_stolen = cpu;
		remote = per_cpu_ptr(pool->tag_cpu, cpu);

		cpumask_clear_cpu(cpu, &pool->cpus_have_tags);

		if (remote == tags)
			continue;

		spin_lock(&remote->lock);

		if (remote->nr_free) {
			memcpy(tags->freelist,
			       remote->freelist,
			       sizeof(unsigned) * remote->nr_free);

			tags->nr_free = remote->nr_free;
			remote->nr_free = 0;
		}

		spin_unlock(&remote->lock);

		if (tags->nr_free)
			break;
	}
}

void native_send_call_func_ipi(const struct cpumask *mask)
{
	cpumask_var_t allbutself;

	if (!alloc_cpumask_var(&allbutself, GFP_ATOMIC)) {
		apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
		return;
	}

	cpumask_copy(allbutself, cpu_online_mask);
	cpumask_clear_cpu(smp_processor_id(), allbutself);

	if (cpumask_equal(mask, allbutself) &&
	    cpumask_equal(cpu_online_mask, cpu_callout_mask))
		apic->send_IPI_allbutself(CALL_FUNCTION_VECTOR);
	else
		apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR);

	free_cpumask_var(allbutself);
}

static int __kprobes
arch_trigger_all_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
{
	int cpu;

	cpu = smp_processor_id();

	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
		static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;

		arch_spin_lock(&lock);
		printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
		show_regs(regs);
		arch_spin_unlock(&lock);
		cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
		return NMI_HANDLED;
	}

	return NMI_DONE;
}

void flush_area_mask(const cpumask_t *mask, const void *va, unsigned int flags)
{
    ASSERT(local_irq_is_enabled());

    if ( cpumask_test_cpu(smp_processor_id(), mask) )
        flush_area_local(va, flags);

    if ( !cpumask_subset(mask, cpumask_of(smp_processor_id())) )
    {
        spin_lock(&flush_lock);
        cpumask_and(&flush_cpumask, mask, &cpu_online_map);
        cpumask_clear_cpu(smp_processor_id(), &flush_cpumask);
        flush_va      = va;
        flush_flags   = flags;
        send_IPI_mask(&flush_cpumask, INVALIDATE_TLB_VECTOR);
        while ( !cpumask_empty(&flush_cpumask) )
            cpu_relax();
        spin_unlock(&flush_lock);
    }
}

int __cpu_disable(void)
{
	unsigned int cpu = smp_processor_id();
	struct task_struct *p;
	int ret;

	ret = mp_ops->cpu_disable(cpu);
	if (ret)
		return ret;

	/*
	 * Take this CPU offline.  Once we clear this, we can't return,
	 * and we must not schedule until we're ready to give up the cpu.
	 */
	set_cpu_online(cpu, false);

	/*
	 * OK - migrate IRQs away from this CPU
	 */
	migrate_irqs();

	/*
	 * Stop the local timer for this CPU.
	 */
	local_timer_stop(cpu);

	/*
	 * Flush user cache and TLB mappings, and then remove this CPU
	 * from the vm mask set of all processes.
	 */
	flush_cache_all();
	local_flush_tlb_all();

	read_lock(&tasklist_lock);
	for_each_process(p)
		if (p->mm)
			cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
	read_unlock(&tasklist_lock);

	return 0;
}

bool nmi_cpu_backtrace(struct pt_regs *regs)
{
	int cpu = smp_processor_id();

	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
		if (regs && cpu_in_idle(instruction_pointer(regs))) {
			pr_warn("NMI backtrace for cpu %d skipped: idling at pc %#lx\n",
				cpu, instruction_pointer(regs));
		} else {
			pr_warn("NMI backtrace for cpu %d\n", cpu);
			if (regs)
				show_regs(regs);
			else
				dump_stack();
		}
		cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
		return true;
	}

	return false;
}

/* Shut down the current CPU */
void __cpu_disable(void)
{
    unsigned int cpu = get_processor_id();

    local_irq_disable();
    gic_disable_cpu();
    /* Allow any queued timer interrupts to get serviced */
    local_irq_enable();
    mdelay(1);
    local_irq_disable();

    /* It's now safe to remove this processor from the online map */
    cpumask_clear_cpu(cpu, &cpu_online_map);

    if ( cpu_disable_scheduler(cpu) )
        BUG();
    smp_mb();

    /* Return to caller; eventually the IPI mechanism will unwind and the 
     * scheduler will drop to the idle loop, which will call stop_cpu(). */
}

void smp_send_stop(void)
{
	unsigned long timeout;

	if (num_online_cpus() > 1) {
		cpumask_t mask;

		cpumask_copy(&mask, cpu_online_mask);
		cpumask_clear_cpu(smp_processor_id(), &mask);

		smp_cross_call(&mask, IPI_CPU_STOP);
	}

	/* Wait up to one second for other CPUs to stop */
	timeout = USEC_PER_SEC;
	while (num_online_cpus() > 1 && timeout--)
		udelay(1);

	if (num_online_cpus() > 1)
		pr_warning("SMP: failed to stop secondary CPUs\n");
}

/* On return cpumask will be altered to indicate CPUs changed.
 * CPUs with states changed will be set in the mask,
 * CPUs with status unchanged will be unset in the mask. */
static int rtas_cpu_state_change_mask(enum rtas_cpu_state state,
				cpumask_var_t cpus)
{
	int cpu;
	int cpuret = 0;
	int ret = 0;

	if (cpumask_empty(cpus))
		return 0;

	for_each_cpu(cpu, cpus) {
		switch (state) {
		case DOWN:
			cpuret = cpu_down(cpu);
			break;
		case UP:
			cpuret = cpu_up(cpu);
			break;
		}
		if (cpuret) {
			pr_debug("%s: cpu_%s for cpu#%d returned %d.\n",
					__func__,
					((state == UP) ? "up" : "down"),
					cpu, cpuret);
			if (!ret)
				ret = cpuret;
			if (state == UP) {
				/* clear bits for unchanged cpus, return */
				cpumask_shift_right(cpus, cpus, cpu);
				cpumask_shift_left(cpus, cpus, cpu);
				break;
			} else {
				/* clear bit for unchanged cpu, continue */
				cpumask_clear_cpu(cpu, cpus);
			}
		}
	}

	return ret;
}

static int __cpuinit mmu_context_cpu_notify(struct notifier_block *self,
					    unsigned long action, void *hcpu)
{
	unsigned int cpu = (unsigned int)(long)hcpu;
#ifdef CONFIG_HOTPLUG_CPU
	struct task_struct *p;
#endif
	/* We don't touch CPU 0 map, it's allocated at aboot and kept
	 * around forever
	 */
	if (cpu == boot_cpuid)
		return NOTIFY_OK;

	switch (action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
		pr_devel("MMU: Allocating stale context map for CPU %d\n", cpu);
		stale_map[cpu] = kzalloc(CTX_MAP_SIZE, GFP_KERNEL);
		break;
#ifdef CONFIG_HOTPLUG_CPU
	case CPU_UP_CANCELED:
	case CPU_UP_CANCELED_FROZEN:
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		pr_devel("MMU: Freeing stale context map for CPU %d\n", cpu);
		kfree(stale_map[cpu]);
		stale_map[cpu] = NULL;

		/* We also clear the cpu_vm_mask bits of CPUs going away */
		read_lock(&tasklist_lock);
		for_each_process(p) {
			if (p->mm)
				cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
		}
		read_unlock(&tasklist_lock);
	break;
#endif /* CONFIG_HOTPLUG_CPU */
	}
	return NOTIFY_OK;
}