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/bootmem.h>
10 * cpumask_next - get the next cpu in a cpumask
11 * @n: the cpu prior to the place to search (ie. return will be > @n)
12 * @srcp: the cpumask pointer
14 * Returns >= nr_cpu_ids if no further cpus set.
16 unsigned int cpumask_next(int n, const struct cpumask *srcp)
18 /* -1 is a legal arg here. */
21 return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1);
23 EXPORT_SYMBOL(cpumask_next);
26 * cpumask_next_and - get the next cpu in *src1p & *src2p
27 * @n: the cpu prior to the place to search (ie. return will be > @n)
28 * @src1p: the first cpumask pointer
29 * @src2p: the second cpumask pointer
31 * Returns >= nr_cpu_ids if no further cpus set in both.
33 int cpumask_next_and(int n, const struct cpumask *src1p,
34 const struct cpumask *src2p)
36 /* -1 is a legal arg here. */
39 return find_next_and_bit(cpumask_bits(src1p), cpumask_bits(src2p),
40 nr_cpumask_bits, n + 1);
42 EXPORT_SYMBOL(cpumask_next_and);
45 * cpumask_any_but - return a "random" in a cpumask, but not this one.
46 * @mask: the cpumask to search
47 * @cpu: the cpu to ignore.
49 * Often used to find any cpu but smp_processor_id() in a mask.
50 * Returns >= nr_cpu_ids if no cpus set.
52 int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
62 EXPORT_SYMBOL(cpumask_any_but);
65 * cpumask_next_wrap - helper to implement for_each_cpu_wrap
66 * @n: the cpu prior to the place to search
67 * @mask: the cpumask pointer
68 * @start: the start point of the iteration
69 * @wrap: assume @n crossing @start terminates the iteration
71 * Returns >= nr_cpu_ids on completion
73 * Note: the @wrap argument is required for the start condition when
74 * we cannot assume @start is set in @mask.
76 int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap)
81 next = cpumask_next(n, mask);
83 if (wrap && n < start && next >= start) {
84 return nr_cpumask_bits;
86 } else if (next >= nr_cpumask_bits) {
94 EXPORT_SYMBOL(cpumask_next_wrap);
96 /* These are not inline because of header tangles. */
97 #ifdef CONFIG_CPUMASK_OFFSTACK
99 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
100 * @mask: pointer to cpumask_var_t where the cpumask is returned
103 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
104 * a nop returning a constant 1 (in <linux/cpumask.h>)
105 * Returns TRUE if memory allocation succeeded, FALSE otherwise.
107 * In addition, mask will be NULL if this fails. Note that gcc is
108 * usually smart enough to know that mask can never be NULL if
109 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
112 bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
114 *mask = kmalloc_node(cpumask_size(), flags, node);
116 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
118 printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
123 return *mask != NULL;
125 EXPORT_SYMBOL(alloc_cpumask_var_node);
127 bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
129 return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
131 EXPORT_SYMBOL(zalloc_cpumask_var_node);
134 * alloc_cpumask_var - allocate a struct cpumask
135 * @mask: pointer to cpumask_var_t where the cpumask is returned
138 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
139 * a nop returning a constant 1 (in <linux/cpumask.h>).
141 * See alloc_cpumask_var_node.
143 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
145 return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);
147 EXPORT_SYMBOL(alloc_cpumask_var);
149 bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
151 return alloc_cpumask_var(mask, flags | __GFP_ZERO);
153 EXPORT_SYMBOL(zalloc_cpumask_var);
156 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
157 * @mask: pointer to cpumask_var_t where the cpumask is returned
159 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
160 * a nop (in <linux/cpumask.h>).
161 * Either returns an allocated (zero-filled) cpumask, or causes the
164 void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
166 *mask = memblock_virt_alloc(cpumask_size(), 0);
170 * free_cpumask_var - frees memory allocated for a struct cpumask.
171 * @mask: cpumask to free
173 * This is safe on a NULL mask.
175 void free_cpumask_var(cpumask_var_t mask)
179 EXPORT_SYMBOL(free_cpumask_var);
182 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
183 * @mask: cpumask to free
185 void __init free_bootmem_cpumask_var(cpumask_var_t mask)
187 memblock_free_early(__pa(mask), cpumask_size());
192 * cpumask_local_spread - select the i'th cpu with local numa cpu's first
194 * @node: local numa_node
196 * This function selects an online CPU according to a numa aware policy;
197 * local cpus are returned first, followed by non-local ones, then it
200 * It's not very efficient, but useful for setup.
202 unsigned int cpumask_local_spread(unsigned int i, int node)
206 /* Wrap: we always want a cpu. */
207 i %= num_online_cpus();
210 for_each_cpu(cpu, cpu_online_mask)
215 for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask)
219 for_each_cpu(cpu, cpu_online_mask) {
220 /* Skip NUMA nodes, done above. */
221 if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
230 EXPORT_SYMBOL(cpumask_local_spread);