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Commit 55db493b authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'cpumask-cleanups' of... 

Merge branch 'cpumask-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

* 'cpumask-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  cpumask: rename tsk_cpumask to tsk_cpus_allowed
  cpumask: don't recommend set_cpus_allowed hack in Documentation/cpu-hotplug.txt
  cpumask: avoid dereferencing struct cpumask
  cpumask: convert drivers/idle/i7300_idle.c to cpumask_var_t
  cpumask: use modern cpumask style in drivers/scsi/fcoe/fcoe.c
  cpumask: avoid deprecated function in mm/slab.c
  cpumask: use cpu_online in kernel/perf_event.c
parents efc8e7f4 a4636818

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