Revision dddd3379a619a4cb8247bfd3c94ca9ae3797aa2e authored by Thomas Gleixner on 24 November 2010, 09:05:55 UTC, committed by Ingo Molnar on 26 November 2010, 14:00:56 UTC
It was found that sometimes children of tasks with inherited events had
one extra event. Eventually it turned out to be due to the list rotation
no being exclusive with the list iteration in the inheritance code.

Cure this by temporarily disabling the rotation while we inherit the events.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
1 parent 02a9d03
Raw File
cpumask.c
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/bootmem.h>

int __first_cpu(const cpumask_t *srcp)
{
	return min_t(int, NR_CPUS, find_first_bit(srcp->bits, NR_CPUS));
}
EXPORT_SYMBOL(__first_cpu);

int __next_cpu(int n, const cpumask_t *srcp)
{
	return min_t(int, NR_CPUS, find_next_bit(srcp->bits, NR_CPUS, n+1));
}
EXPORT_SYMBOL(__next_cpu);

#if NR_CPUS > 64
int __next_cpu_nr(int n, const cpumask_t *srcp)
{
	return min_t(int, nr_cpu_ids,
				find_next_bit(srcp->bits, nr_cpu_ids, n+1));
}
EXPORT_SYMBOL(__next_cpu_nr);
#endif

int __any_online_cpu(const cpumask_t *mask)
{
	int cpu;

	for_each_cpu_mask(cpu, *mask) {
		if (cpu_online(cpu))
			break;
	}
	return cpu;
}
EXPORT_SYMBOL(__any_online_cpu);

/**
 * cpumask_next_and - get the next cpu in *src1p & *src2p
 * @n: the cpu prior to the place to search (ie. return will be > @n)
 * @src1p: the first cpumask pointer
 * @src2p: the second cpumask pointer
 *
 * Returns >= nr_cpu_ids if no further cpus set in both.
 */
int cpumask_next_and(int n, const struct cpumask *src1p,
		     const struct cpumask *src2p)
{
	while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
		if (cpumask_test_cpu(n, src2p))
			break;
	return n;
}
EXPORT_SYMBOL(cpumask_next_and);

/**
 * cpumask_any_but - return a "random" in a cpumask, but not this one.
 * @mask: the cpumask to search
 * @cpu: the cpu to ignore.
 *
 * Often used to find any cpu but smp_processor_id() in a mask.
 * Returns >= nr_cpu_ids if no cpus set.
 */
int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
{
	unsigned int i;

	cpumask_check(cpu);
	for_each_cpu(i, mask)
		if (i != cpu)
			break;
	return i;
}

/* These are not inline because of header tangles. */
#ifdef CONFIG_CPUMASK_OFFSTACK
/**
 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
 * @mask: pointer to cpumask_var_t where the cpumask is returned
 * @flags: GFP_ flags
 *
 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
 * a nop returning a constant 1 (in <linux/cpumask.h>)
 * Returns TRUE if memory allocation succeeded, FALSE otherwise.
 *
 * In addition, mask will be NULL if this fails.  Note that gcc is
 * usually smart enough to know that mask can never be NULL if
 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
 * too.
 */
bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
{
	*mask = kmalloc_node(cpumask_size(), flags, node);

#ifdef CONFIG_DEBUG_PER_CPU_MAPS
	if (!*mask) {
		printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
		dump_stack();
	}
#endif
	/* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */
	if (*mask) {
		unsigned char *ptr = (unsigned char *)cpumask_bits(*mask);
		unsigned int tail;
		tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long);
		memset(ptr + cpumask_size() - tail, 0, tail);
	}

	return *mask != NULL;
}
EXPORT_SYMBOL(alloc_cpumask_var_node);

bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
{
	return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
}
EXPORT_SYMBOL(zalloc_cpumask_var_node);

/**
 * alloc_cpumask_var - allocate a struct cpumask
 * @mask: pointer to cpumask_var_t where the cpumask is returned
 * @flags: GFP_ flags
 *
 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
 * a nop returning a constant 1 (in <linux/cpumask.h>).
 *
 * See alloc_cpumask_var_node.
 */
bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
{
	return alloc_cpumask_var_node(mask, flags, numa_node_id());
}
EXPORT_SYMBOL(alloc_cpumask_var);

bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
{
	return alloc_cpumask_var(mask, flags | __GFP_ZERO);
}
EXPORT_SYMBOL(zalloc_cpumask_var);

/**
 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
 * @mask: pointer to cpumask_var_t where the cpumask is returned
 *
 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
 * a nop (in <linux/cpumask.h>).
 * Either returns an allocated (zero-filled) cpumask, or causes the
 * system to panic.
 */
void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
{
	*mask = alloc_bootmem(cpumask_size());
}

/**
 * free_cpumask_var - frees memory allocated for a struct cpumask.
 * @mask: cpumask to free
 *
 * This is safe on a NULL mask.
 */
void free_cpumask_var(cpumask_var_t mask)
{
	kfree(mask);
}
EXPORT_SYMBOL(free_cpumask_var);

/**
 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
 * @mask: cpumask to free
 */
void __init free_bootmem_cpumask_var(cpumask_var_t mask)
{
	free_bootmem((unsigned long)mask, cpumask_size());
}
#endif
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