1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/slab.h>
  3#include <linux/kernel.h>
  4#include <linux/bitops.h>
  5#include <linux/cpumask.h>
  6#include <linux/export.h>
  7#include <linux/memblock.h>
  8#include <linux/numa.h>
  9
 10/**
 11 * cpumask_next_wrap - helper to implement for_each_cpu_wrap
 12 * @n: the cpu prior to the place to search
 13 * @mask: the cpumask pointer
 14 * @start: the start point of the iteration
 15 * @wrap: assume @n crossing @start terminates the iteration
 16 *
 17 * Return: >= nr_cpu_ids on completion
 18 *
 19 * Note: the @wrap argument is required for the start condition when
 20 * we cannot assume @start is set in @mask.
 21 */
 22unsigned int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap)
 23{
 24	unsigned int next;
 
 
 25
 26again:
 27	next = cpumask_next(n, mask);
 
 
 
 
 
 
 28
 29	if (wrap && n < start && next >= start) {
 30		return nr_cpumask_bits;
 
 31
 32	} else if (next >= nr_cpumask_bits) {
 33		wrap = true;
 34		n = -1;
 35		goto again;
 36	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 37
 38	return next;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 39}
 40EXPORT_SYMBOL(cpumask_next_wrap);
 41
 42/* These are not inline because of header tangles. */
 43#ifdef CONFIG_CPUMASK_OFFSTACK
 44/**
 45 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
 46 * @mask: pointer to cpumask_var_t where the cpumask is returned
 47 * @flags: GFP_ flags
 48 * @node: memory node from which to allocate or %NUMA_NO_NODE
 49 *
 50 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
 51 * a nop returning a constant 1 (in <linux/cpumask.h>).
 52 *
 53 * Return: TRUE if memory allocation succeeded, FALSE otherwise.
 54 *
 55 * In addition, mask will be NULL if this fails.  Note that gcc is
 56 * usually smart enough to know that mask can never be NULL if
 57 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
 58 * too.
 59 */
 60bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
 61{
 62	*mask = kmalloc_node(cpumask_size(), flags, node);
 63
 64#ifdef CONFIG_DEBUG_PER_CPU_MAPS
 65	if (!*mask) {
 66		printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
 67		dump_stack();
 68	}
 69#endif
 
 
 
 
 
 
 
 70
 71	return *mask != NULL;
 72}
 73EXPORT_SYMBOL(alloc_cpumask_var_node);
 74
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 75/**
 76 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
 77 * @mask: pointer to cpumask_var_t where the cpumask is returned
 78 *
 79 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
 80 * a nop (in <linux/cpumask.h>).
 81 * Either returns an allocated (zero-filled) cpumask, or causes the
 82 * system to panic.
 83 */
 84void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
 85{
 86	*mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES);
 87	if (!*mask)
 88		panic("%s: Failed to allocate %u bytes\n", __func__,
 89		      cpumask_size());
 90}
 91
 92/**
 93 * free_cpumask_var - frees memory allocated for a struct cpumask.
 94 * @mask: cpumask to free
 95 *
 96 * This is safe on a NULL mask.
 97 */
 98void free_cpumask_var(cpumask_var_t mask)
 99{
100	kfree(mask);
101}
102EXPORT_SYMBOL(free_cpumask_var);
103
104/**
105 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
106 * @mask: cpumask to free
107 */
108void __init free_bootmem_cpumask_var(cpumask_var_t mask)
109{
110	memblock_free(mask, cpumask_size());
111}
112#endif
113
114/**
115 * cpumask_local_spread - select the i'th cpu based on NUMA distances
116 * @i: index number
117 * @node: local numa_node
118 *
119 * Return: online CPU according to a numa aware policy; local cpus are returned
120 * first, followed by non-local ones, then it wraps around.
121 *
122 * For those who wants to enumerate all CPUs based on their NUMA distances,
123 * i.e. call this function in a loop, like:
124 *
125 * for (i = 0; i < num_online_cpus(); i++) {
126 *	cpu = cpumask_local_spread(i, node);
127 *	do_something(cpu);
128 * }
129 *
130 * There's a better alternative based on for_each()-like iterators:
131 *
132 *	for_each_numa_hop_mask(mask, node) {
133 *		for_each_cpu_andnot(cpu, mask, prev)
134 *			do_something(cpu);
135 *		prev = mask;
136 *	}
137 *
138 * It's simpler and more verbose than above. Complexity of iterator-based
139 * enumeration is O(sched_domains_numa_levels * nr_cpu_ids), while
140 * cpumask_local_spread() when called for each cpu is
141 * O(sched_domains_numa_levels * nr_cpu_ids * log(nr_cpu_ids)).
142 */
143unsigned int cpumask_local_spread(unsigned int i, int node)
144{
145	unsigned int cpu;
146
147	/* Wrap: we always want a cpu. */
148	i %= num_online_cpus();
149
150	cpu = sched_numa_find_nth_cpu(cpu_online_mask, i, node);
151
152	WARN_ON(cpu >= nr_cpu_ids);
153	return cpu;
154}
155EXPORT_SYMBOL(cpumask_local_spread);
156
157static DEFINE_PER_CPU(int, distribute_cpu_mask_prev);
158
159/**
160 * cpumask_any_and_distribute - Return an arbitrary cpu within src1p & src2p.
161 * @src1p: first &cpumask for intersection
162 * @src2p: second &cpumask for intersection
163 *
164 * Iterated calls using the same srcp1 and srcp2 will be distributed within
165 * their intersection.
166 *
167 * Return: >= nr_cpu_ids if the intersection is empty.
168 */
169unsigned int cpumask_any_and_distribute(const struct cpumask *src1p,
170			       const struct cpumask *src2p)
171{
172	unsigned int next, prev;
173
174	/* NOTE: our first selection will skip 0. */
175	prev = __this_cpu_read(distribute_cpu_mask_prev);
176
177	next = find_next_and_bit_wrap(cpumask_bits(src1p), cpumask_bits(src2p),
178					nr_cpumask_bits, prev + 1);
179	if (next < nr_cpu_ids)
180		__this_cpu_write(distribute_cpu_mask_prev, next);
181
182	return next;
183}
184EXPORT_SYMBOL(cpumask_any_and_distribute);
185
186/**
187 * cpumask_any_distribute - Return an arbitrary cpu from srcp
188 * @srcp: &cpumask for selection
189 *
190 * Return: >= nr_cpu_ids if the intersection is empty.
191 */
192unsigned int cpumask_any_distribute(const struct cpumask *srcp)
193{
194	unsigned int next, prev;
195
196	/* NOTE: our first selection will skip 0. */
197	prev = __this_cpu_read(distribute_cpu_mask_prev);
198	next = find_next_bit_wrap(cpumask_bits(srcp), nr_cpumask_bits, prev + 1);
199	if (next < nr_cpu_ids)
200		__this_cpu_write(distribute_cpu_mask_prev, next);
201
202	return next;
203}
204EXPORT_SYMBOL(cpumask_any_distribute);

 
  1#include <linux/slab.h>
  2#include <linux/kernel.h>
  3#include <linux/bitops.h>
  4#include <linux/cpumask.h>
  5#include <linux/module.h>
  6#include <linux/bootmem.h>
 
  7
  8int __first_cpu(const cpumask_t *srcp)
  9{
 10	return min_t(int, NR_CPUS, find_first_bit(srcp->bits, NR_CPUS));
 11}
 12EXPORT_SYMBOL(__first_cpu);
 13
 14int __next_cpu(int n, const cpumask_t *srcp)
 
 
 
 
 
 
 15{
 16	return min_t(int, NR_CPUS, find_next_bit(srcp->bits, NR_CPUS, n+1));
 17}
 18EXPORT_SYMBOL(__next_cpu);
 19
 20#if NR_CPUS > 64
 21int __next_cpu_nr(int n, const cpumask_t *srcp)
 22{
 23	return min_t(int, nr_cpu_ids,
 24				find_next_bit(srcp->bits, nr_cpu_ids, n+1));
 25}
 26EXPORT_SYMBOL(__next_cpu_nr);
 27#endif
 28
 29int __any_online_cpu(const cpumask_t *mask)
 30{
 31	int cpu;
 32
 33	for_each_cpu(cpu, mask) {
 34		if (cpu_online(cpu))
 35			break;
 
 36	}
 37	return cpu;
 38}
 39EXPORT_SYMBOL(__any_online_cpu);
 40
 41/**
 42 * cpumask_next_and - get the next cpu in *src1p & *src2p
 43 * @n: the cpu prior to the place to search (ie. return will be > @n)
 44 * @src1p: the first cpumask pointer
 45 * @src2p: the second cpumask pointer
 46 *
 47 * Returns >= nr_cpu_ids if no further cpus set in both.
 48 */
 49int cpumask_next_and(int n, const struct cpumask *src1p,
 50		     const struct cpumask *src2p)
 51{
 52	while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
 53		if (cpumask_test_cpu(n, src2p))
 54			break;
 55	return n;
 56}
 57EXPORT_SYMBOL(cpumask_next_and);
 58
 59/**
 60 * cpumask_any_but - return a "random" in a cpumask, but not this one.
 61 * @mask: the cpumask to search
 62 * @cpu: the cpu to ignore.
 63 *
 64 * Often used to find any cpu but smp_processor_id() in a mask.
 65 * Returns >= nr_cpu_ids if no cpus set.
 66 */
 67int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
 68{
 69	unsigned int i;
 70
 71	cpumask_check(cpu);
 72	for_each_cpu(i, mask)
 73		if (i != cpu)
 74			break;
 75	return i;
 76}
 
 77
 78/* These are not inline because of header tangles. */
 79#ifdef CONFIG_CPUMASK_OFFSTACK
 80/**
 81 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
 82 * @mask: pointer to cpumask_var_t where the cpumask is returned
 83 * @flags: GFP_ flags
 
 84 *
 85 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
 86 * a nop returning a constant 1 (in <linux/cpumask.h>)
 87 * Returns TRUE if memory allocation succeeded, FALSE otherwise.
 
 88 *
 89 * In addition, mask will be NULL if this fails.  Note that gcc is
 90 * usually smart enough to know that mask can never be NULL if
 91 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
 92 * too.
 93 */
 94bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
 95{
 96	*mask = kmalloc_node(cpumask_size(), flags, node);
 97
 98#ifdef CONFIG_DEBUG_PER_CPU_MAPS
 99	if (!*mask) {
100		printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
101		dump_stack();
102	}
103#endif
104	/* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */
105	if (*mask) {
106		unsigned char *ptr = (unsigned char *)cpumask_bits(*mask);
107		unsigned int tail;
108		tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long);
109		memset(ptr + cpumask_size() - tail, 0, tail);
110	}
111
112	return *mask != NULL;
113}
114EXPORT_SYMBOL(alloc_cpumask_var_node);
115
116bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
117{
118	return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
119}
120EXPORT_SYMBOL(zalloc_cpumask_var_node);
121
122/**
123 * alloc_cpumask_var - allocate a struct cpumask
124 * @mask: pointer to cpumask_var_t where the cpumask is returned
125 * @flags: GFP_ flags
126 *
127 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
128 * a nop returning a constant 1 (in <linux/cpumask.h>).
129 *
130 * See alloc_cpumask_var_node.
131 */
132bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
133{
134	return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);
135}
136EXPORT_SYMBOL(alloc_cpumask_var);
137
138bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
139{
140	return alloc_cpumask_var(mask, flags | __GFP_ZERO);
141}
142EXPORT_SYMBOL(zalloc_cpumask_var);
143
144/**
145 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
146 * @mask: pointer to cpumask_var_t where the cpumask is returned
147 *
148 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
149 * a nop (in <linux/cpumask.h>).
150 * Either returns an allocated (zero-filled) cpumask, or causes the
151 * system to panic.
152 */
153void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
154{
155	*mask = alloc_bootmem(cpumask_size());
 
 
 
156}
157
158/**
159 * free_cpumask_var - frees memory allocated for a struct cpumask.
160 * @mask: cpumask to free
161 *
162 * This is safe on a NULL mask.
163 */
164void free_cpumask_var(cpumask_var_t mask)
165{
166	kfree(mask);
167}
168EXPORT_SYMBOL(free_cpumask_var);
169
170/**
171 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
172 * @mask: cpumask to free
173 */
174void __init free_bootmem_cpumask_var(cpumask_var_t mask)
175{
176	free_bootmem((unsigned long)mask, cpumask_size());
177}
178#endif