Loading...
1#include <linux/slab.h>
2#include <linux/kernel.h>
3#include <linux/bitops.h>
4#include <linux/cpumask.h>
5#include <linux/export.h>
6#include <linux/bootmem.h>
7
8/**
9 * cpumask_next_and - get the next cpu in *src1p & *src2p
10 * @n: the cpu prior to the place to search (ie. return will be > @n)
11 * @src1p: the first cpumask pointer
12 * @src2p: the second cpumask pointer
13 *
14 * Returns >= nr_cpu_ids if no further cpus set in both.
15 */
16int cpumask_next_and(int n, const struct cpumask *src1p,
17 const struct cpumask *src2p)
18{
19 while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
20 if (cpumask_test_cpu(n, src2p))
21 break;
22 return n;
23}
24EXPORT_SYMBOL(cpumask_next_and);
25
26/**
27 * cpumask_any_but - return a "random" in a cpumask, but not this one.
28 * @mask: the cpumask to search
29 * @cpu: the cpu to ignore.
30 *
31 * Often used to find any cpu but smp_processor_id() in a mask.
32 * Returns >= nr_cpu_ids if no cpus set.
33 */
34int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
35{
36 unsigned int i;
37
38 cpumask_check(cpu);
39 for_each_cpu(i, mask)
40 if (i != cpu)
41 break;
42 return i;
43}
44EXPORT_SYMBOL(cpumask_any_but);
45
46/* These are not inline because of header tangles. */
47#ifdef CONFIG_CPUMASK_OFFSTACK
48/**
49 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
50 * @mask: pointer to cpumask_var_t where the cpumask is returned
51 * @flags: GFP_ flags
52 *
53 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
54 * a nop returning a constant 1 (in <linux/cpumask.h>)
55 * Returns TRUE if memory allocation succeeded, FALSE otherwise.
56 *
57 * In addition, mask will be NULL if this fails. Note that gcc is
58 * usually smart enough to know that mask can never be NULL if
59 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
60 * too.
61 */
62bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
63{
64 *mask = kmalloc_node(cpumask_size(), flags, node);
65
66#ifdef CONFIG_DEBUG_PER_CPU_MAPS
67 if (!*mask) {
68 printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
69 dump_stack();
70 }
71#endif
72
73 return *mask != NULL;
74}
75EXPORT_SYMBOL(alloc_cpumask_var_node);
76
77bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
78{
79 return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
80}
81EXPORT_SYMBOL(zalloc_cpumask_var_node);
82
83/**
84 * alloc_cpumask_var - allocate a struct cpumask
85 * @mask: pointer to cpumask_var_t where the cpumask is returned
86 * @flags: GFP_ flags
87 *
88 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
89 * a nop returning a constant 1 (in <linux/cpumask.h>).
90 *
91 * See alloc_cpumask_var_node.
92 */
93bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
94{
95 return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);
96}
97EXPORT_SYMBOL(alloc_cpumask_var);
98
99bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
100{
101 return alloc_cpumask_var(mask, flags | __GFP_ZERO);
102}
103EXPORT_SYMBOL(zalloc_cpumask_var);
104
105/**
106 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
107 * @mask: pointer to cpumask_var_t where the cpumask is returned
108 *
109 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
110 * a nop (in <linux/cpumask.h>).
111 * Either returns an allocated (zero-filled) cpumask, or causes the
112 * system to panic.
113 */
114void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
115{
116 *mask = memblock_virt_alloc(cpumask_size(), 0);
117}
118
119/**
120 * free_cpumask_var - frees memory allocated for a struct cpumask.
121 * @mask: cpumask to free
122 *
123 * This is safe on a NULL mask.
124 */
125void free_cpumask_var(cpumask_var_t mask)
126{
127 kfree(mask);
128}
129EXPORT_SYMBOL(free_cpumask_var);
130
131/**
132 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
133 * @mask: cpumask to free
134 */
135void __init free_bootmem_cpumask_var(cpumask_var_t mask)
136{
137 memblock_free_early(__pa(mask), cpumask_size());
138}
139#endif
140
141/**
142 * cpumask_local_spread - select the i'th cpu with local numa cpu's first
143 * @i: index number
144 * @node: local numa_node
145 *
146 * This function selects an online CPU according to a numa aware policy;
147 * local cpus are returned first, followed by non-local ones, then it
148 * wraps around.
149 *
150 * It's not very efficient, but useful for setup.
151 */
152unsigned int cpumask_local_spread(unsigned int i, int node)
153{
154 int cpu;
155
156 /* Wrap: we always want a cpu. */
157 i %= num_online_cpus();
158
159 if (node == -1) {
160 for_each_cpu(cpu, cpu_online_mask)
161 if (i-- == 0)
162 return cpu;
163 } else {
164 /* NUMA first. */
165 for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask)
166 if (i-- == 0)
167 return cpu;
168
169 for_each_cpu(cpu, cpu_online_mask) {
170 /* Skip NUMA nodes, done above. */
171 if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
172 continue;
173
174 if (i-- == 0)
175 return cpu;
176 }
177 }
178 BUG();
179}
180EXPORT_SYMBOL(cpumask_local_spread);
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 * Returns >= 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 *
49 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
50 * a nop returning a constant 1 (in <linux/cpumask.h>)
51 * Returns TRUE if memory allocation succeeded, FALSE otherwise.
52 *
53 * In addition, mask will be NULL if this fails. Note that gcc is
54 * usually smart enough to know that mask can never be NULL if
55 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
56 * too.
57 */
58bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
59{
60 *mask = kmalloc_node(cpumask_size(), flags, node);
61
62#ifdef CONFIG_DEBUG_PER_CPU_MAPS
63 if (!*mask) {
64 printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
65 dump_stack();
66 }
67#endif
68
69 return *mask != NULL;
70}
71EXPORT_SYMBOL(alloc_cpumask_var_node);
72
73/**
74 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
75 * @mask: pointer to cpumask_var_t where the cpumask is returned
76 *
77 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
78 * a nop (in <linux/cpumask.h>).
79 * Either returns an allocated (zero-filled) cpumask, or causes the
80 * system to panic.
81 */
82void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
83{
84 *mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES);
85 if (!*mask)
86 panic("%s: Failed to allocate %u bytes\n", __func__,
87 cpumask_size());
88}
89
90/**
91 * free_cpumask_var - frees memory allocated for a struct cpumask.
92 * @mask: cpumask to free
93 *
94 * This is safe on a NULL mask.
95 */
96void free_cpumask_var(cpumask_var_t mask)
97{
98 kfree(mask);
99}
100EXPORT_SYMBOL(free_cpumask_var);
101
102/**
103 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
104 * @mask: cpumask to free
105 */
106void __init free_bootmem_cpumask_var(cpumask_var_t mask)
107{
108 memblock_free(mask, cpumask_size());
109}
110#endif
111
112/**
113 * cpumask_local_spread - select the i'th cpu with local numa cpu's first
114 * @i: index number
115 * @node: local numa_node
116 *
117 * This function selects an online CPU according to a numa aware policy;
118 * local cpus are returned first, followed by non-local ones, then it
119 * wraps around.
120 *
121 * It's not very efficient, but useful for setup.
122 */
123unsigned int cpumask_local_spread(unsigned int i, int node)
124{
125 unsigned int cpu;
126
127 /* Wrap: we always want a cpu. */
128 i %= num_online_cpus();
129
130 if (node == NUMA_NO_NODE) {
131 cpu = cpumask_nth(i, cpu_online_mask);
132 if (cpu < nr_cpu_ids)
133 return cpu;
134 } else {
135 /* NUMA first. */
136 cpu = cpumask_nth_and(i, cpu_online_mask, cpumask_of_node(node));
137 if (cpu < nr_cpu_ids)
138 return cpu;
139
140 i -= cpumask_weight_and(cpu_online_mask, cpumask_of_node(node));
141
142 /* Skip NUMA nodes, done above. */
143 cpu = cpumask_nth_andnot(i, cpu_online_mask, cpumask_of_node(node));
144 if (cpu < nr_cpu_ids)
145 return cpu;
146 }
147 BUG();
148}
149EXPORT_SYMBOL(cpumask_local_spread);
150
151static DEFINE_PER_CPU(int, distribute_cpu_mask_prev);
152
153/**
154 * Returns an arbitrary cpu within srcp1 & srcp2.
155 *
156 * Iterated calls using the same srcp1 and srcp2 will be distributed within
157 * their intersection.
158 *
159 * Returns >= nr_cpu_ids if the intersection is empty.
160 */
161unsigned int cpumask_any_and_distribute(const struct cpumask *src1p,
162 const struct cpumask *src2p)
163{
164 unsigned int next, prev;
165
166 /* NOTE: our first selection will skip 0. */
167 prev = __this_cpu_read(distribute_cpu_mask_prev);
168
169 next = find_next_and_bit_wrap(cpumask_bits(src1p), cpumask_bits(src2p),
170 nr_cpumask_bits, prev + 1);
171 if (next < nr_cpu_ids)
172 __this_cpu_write(distribute_cpu_mask_prev, next);
173
174 return next;
175}
176EXPORT_SYMBOL(cpumask_any_and_distribute);
177
178unsigned int cpumask_any_distribute(const struct cpumask *srcp)
179{
180 unsigned int next, prev;
181
182 /* NOTE: our first selection will skip 0. */
183 prev = __this_cpu_read(distribute_cpu_mask_prev);
184 next = find_next_bit_wrap(cpumask_bits(srcp), nr_cpumask_bits, prev + 1);
185 if (next < nr_cpu_ids)
186 __this_cpu_write(distribute_cpu_mask_prev, next);
187
188 return next;
189}
190EXPORT_SYMBOL(cpumask_any_distribute);