Merge branch 'cpumask-cleanups' of... (55db493b) · Commits · 戴 / test

Documentation/cpu-hotplug.txt

+17 −32

Original line number	Diff line number	Diff line
		@@ -315,42 +315,27 @@ A: The following are what is required for CPU hotplug infrastructure to work

		Q: I need to ensure that a particular cpu is not removed when there is some
		work specific to this cpu is in progress.
		A: First switch the current thread context to preferred cpu
		A: There are two ways. If your code can be run in interrupt context, use
		smp_call_function_single(), otherwise use work_on_cpu(). Note that
		work_on_cpu() is slow, and can fail due to out of memory:

		int my_func_on_cpu(int cpu)
		{
		cpumask_t saved_mask, new_mask = CPU_MASK_NONE;
		int curr_cpu, err = 0;

		saved_mask = current->cpus_allowed;
		cpu_set(cpu, new_mask);
		err = set_cpus_allowed(current, new_mask);

		if (err)
		return err;

		/*
		* If we got scheduled out just after the return from
		* set_cpus_allowed() before running the work, this ensures
		* we stay locked.
		*/
		curr_cpu = get_cpu();

		if (curr_cpu != cpu) {
		err = -EAGAIN;
		goto ret;
		} else {
		/*
		* Do work : But cant sleep, since get_cpu() disables preempt
		*/
		}
		ret:
		put_cpu();
		set_cpus_allowed(current, saved_mask);
		int err;
		get_online_cpus();
		if (!cpu_online(cpu))
		err = -EINVAL;
		else
		#if NEEDS_BLOCKING
		err = work_on_cpu(cpu, __my_func_on_cpu, NULL);
		#else
		smp_call_function_single(cpu, __my_func_on_cpu, &err,
		true);
		#endif
		put_online_cpus();
		return err;
		}


		Q: How do we determine how many CPUs are available for hotplug.
		A: There is no clear spec defined way from ACPI that can give us that
		information today. Based on some input from Natalie of Unisys,

arch/x86/kernel/cpu/cpufreq/powernow-k8.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1136,7 +1136,7 @@ static int powernowk8_target(struct cpufreq_policy *pol,
		if (!alloc_cpumask_var(&oldmask, GFP_KERNEL))
		return -ENOMEM;

		cpumask_copy(oldmask, tsk_cpumask(current));
		cpumask_copy(oldmask, tsk_cpus_allowed(current));
		set_cpus_allowed_ptr(current, cpumask_of(pol->cpu));

		if (smp_processor_id() != pol->cpu) {

drivers/idle/i7300_idle.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -81,7 +81,7 @@ static u8 i7300_idle_thrtctl_saved;
		static u8 i7300_idle_thrtlow_saved;
		static u32 i7300_idle_mc_saved;

		static cpumask_t idle_cpumask;
		static cpumask_var_t idle_cpumask;
		static ktime_t start_ktime;
		static unsigned long avg_idle_us;

		@@ -459,9 +459,9 @@ static int i7300_idle_notifier(struct notifier_block *nb, unsigned long val,
		spin_lock_irqsave(&i7300_idle_lock, flags);
		if (val == IDLE_START) {

		cpu_set(smp_processor_id(), idle_cpumask);
		cpumask_set_cpu(smp_processor_id(), idle_cpumask);

		if (cpus_weight(idle_cpumask) != num_online_cpus())
		if (cpumask_weight(idle_cpumask) != num_online_cpus())
		goto end;

		now_ktime = ktime_get();
		@@ -478,8 +478,8 @@ static int i7300_idle_notifier(struct notifier_block *nb, unsigned long val,
		i7300_idle_ioat_start();

		} else if (val == IDLE_END) {
		cpu_clear(smp_processor_id(), idle_cpumask);
		if (cpus_weight(idle_cpumask) == (num_online_cpus() - 1)) {
		cpumask_clear_cpu(smp_processor_id(), idle_cpumask);
		if (cpumask_weight(idle_cpumask) == (num_online_cpus() - 1)) {
		/* First CPU coming out of idle */
		u64 idle_duration_us;

		@@ -553,7 +553,6 @@ struct debugfs_file_info {
		static int __init i7300_idle_init(void)
		{
		spin_lock_init(&i7300_idle_lock);
		cpus_clear(idle_cpumask);
		total_us = 0;

		if (i7300_idle_platform_probe(&fbd_dev, &ioat_dev, forceload))
		@@ -565,6 +564,9 @@ static int __init i7300_idle_init(void)
		if (i7300_idle_ioat_init())
		return -ENODEV;

		if (!zalloc_cpumask_var(&idle_cpumask, GFP_KERNEL))
		return -ENOMEM;

		debugfs_dir = debugfs_create_dir("i7300_idle", NULL);
		if (debugfs_dir) {
		int i = 0;
		@@ -589,6 +591,7 @@ static int __init i7300_idle_init(void)
		static void __exit i7300_idle_exit(void)
		{
		idle_notifier_unregister(&i7300_idle_nb);
		free_cpumask_var(idle_cpumask);

		if (debugfs_dir) {
		int i = 0;

drivers/scsi/fcoe/fcoe.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1260,7 +1260,7 @@ int fcoe_rcv(struct sk_buff skb, struct net_device netdev,
		"CPU.\n");

		spin_unlock_bh(&fps->fcoe_rx_list.lock);
		cpu = first_cpu(cpu_online_map);
		cpu = cpumask_first(cpu_online_mask);
		fps = &per_cpu(fcoe_percpu, cpu);
		spin_lock_bh(&fps->fcoe_rx_list.lock);
		if (!fps->thread) {

include/linux/sched.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -1553,7 +1553,7 @@ struct task_struct {
		};

		/* Future-safe accessor for struct task_struct's cpus_allowed. */
		#define tsk_cpumask(tsk) (&(tsk)->cpus_allowed)
		#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)

		/*
		* Priority of a process goes from 0..MAX_PRIO-1, valid RT

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