Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
5a0e3ad6 | 2 | #include <linux/slab.h> |
ccb46000 AM |
3 | #include <linux/kernel.h> |
4 | #include <linux/bitops.h> | |
5 | #include <linux/cpumask.h> | |
8bc3bcc9 | 6 | #include <linux/export.h> |
57c8a661 | 7 | #include <linux/memblock.h> |
98fa15f3 | 8 | #include <linux/numa.h> |
ccb46000 | 9 | |
c743f0a5 PZ |
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 | */ | |
8b6b795d | 22 | unsigned int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap) |
c743f0a5 | 23 | { |
8b6b795d | 24 | unsigned int next; |
c743f0a5 PZ |
25 | |
26 | again: | |
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 | } | |
40 | EXPORT_SYMBOL(cpumask_next_wrap); | |
41 | ||
2d3854a3 RR |
42 | /* These are not inline because of header tangles. */ |
43 | #ifdef CONFIG_CPUMASK_OFFSTACK | |
ec26b805 MT |
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 | |
dcb60f9c | 48 | * @node: memory node from which to allocate or %NUMA_NO_NODE |
ec26b805 MT |
49 | * |
50 | * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is | |
51 | * a nop returning a constant 1 (in <linux/cpumask.h>) | |
52 | * Returns TRUE if memory allocation succeeded, FALSE otherwise. | |
53 | * | |
54 | * In addition, mask will be NULL if this fails. Note that gcc is | |
55 | * usually smart enough to know that mask can never be NULL if | |
56 | * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case | |
57 | * too. | |
58 | */ | |
7b4967c5 | 59 | bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) |
2d3854a3 | 60 | { |
38c7fed2 YL |
61 | *mask = kmalloc_node(cpumask_size(), flags, node); |
62 | ||
2d3854a3 RR |
63 | #ifdef CONFIG_DEBUG_PER_CPU_MAPS |
64 | if (!*mask) { | |
65 | printk(KERN_ERR "=> alloc_cpumask_var: failed!\n"); | |
66 | dump_stack(); | |
67 | } | |
68 | #endif | |
2a530080 | 69 | |
2d3854a3 RR |
70 | return *mask != NULL; |
71 | } | |
7b4967c5 MT |
72 | EXPORT_SYMBOL(alloc_cpumask_var_node); |
73 | ||
ec26b805 MT |
74 | /** |
75 | * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena. | |
76 | * @mask: pointer to cpumask_var_t where the cpumask is returned | |
77 | * | |
78 | * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is | |
e9690a6e | 79 | * a nop (in <linux/cpumask.h>). |
ec26b805 MT |
80 | * Either returns an allocated (zero-filled) cpumask, or causes the |
81 | * system to panic. | |
82 | */ | |
2d3854a3 RR |
83 | void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask) |
84 | { | |
7e1c4e27 | 85 | *mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES); |
8a7f97b9 MR |
86 | if (!*mask) |
87 | panic("%s: Failed to allocate %u bytes\n", __func__, | |
88 | cpumask_size()); | |
2d3854a3 RR |
89 | } |
90 | ||
ec26b805 MT |
91 | /** |
92 | * free_cpumask_var - frees memory allocated for a struct cpumask. | |
93 | * @mask: cpumask to free | |
94 | * | |
95 | * This is safe on a NULL mask. | |
96 | */ | |
2d3854a3 RR |
97 | void free_cpumask_var(cpumask_var_t mask) |
98 | { | |
99 | kfree(mask); | |
100 | } | |
101 | EXPORT_SYMBOL(free_cpumask_var); | |
cd83e42c | 102 | |
ec26b805 MT |
103 | /** |
104 | * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var | |
105 | * @mask: cpumask to free | |
106 | */ | |
984f2f37 | 107 | void __init free_bootmem_cpumask_var(cpumask_var_t mask) |
cd83e42c | 108 | { |
4421cca0 | 109 | memblock_free(mask, cpumask_size()); |
cd83e42c | 110 | } |
2d3854a3 | 111 | #endif |
da91309e AV |
112 | |
113 | /** | |
406d394a | 114 | * cpumask_local_spread - select the i'th cpu based on NUMA distances |
da91309e | 115 | * @i: index number |
f36963c9 | 116 | * @node: local numa_node |
da91309e | 117 | * |
2ac4980c YN |
118 | * Returns online CPU according to a numa aware policy; local cpus are returned |
119 | * first, followed by non-local ones, then it wraps around. | |
da91309e | 120 | * |
2ac4980c YN |
121 | * For those who wants to enumerate all CPUs based on their NUMA distances, |
122 | * i.e. call this function in a loop, like: | |
123 | * | |
124 | * for (i = 0; i < num_online_cpus(); i++) { | |
125 | * cpu = cpumask_local_spread(i, node); | |
126 | * do_something(cpu); | |
127 | * } | |
128 | * | |
129 | * There's a better alternative based on for_each()-like iterators: | |
130 | * | |
131 | * for_each_numa_hop_mask(mask, node) { | |
132 | * for_each_cpu_andnot(cpu, mask, prev) | |
133 | * do_something(cpu); | |
134 | * prev = mask; | |
135 | * } | |
136 | * | |
137 | * It's simpler and more verbose than above. Complexity of iterator-based | |
138 | * enumeration is O(sched_domains_numa_levels * nr_cpu_ids), while | |
139 | * cpumask_local_spread() when called for each cpu is | |
140 | * O(sched_domains_numa_levels * nr_cpu_ids * log(nr_cpu_ids)). | |
da91309e | 141 | */ |
f36963c9 | 142 | unsigned int cpumask_local_spread(unsigned int i, int node) |
da91309e | 143 | { |
8b6b795d | 144 | unsigned int cpu; |
da91309e | 145 | |
f36963c9 | 146 | /* Wrap: we always want a cpu. */ |
2452483d | 147 | i %= num_online_cpus(); |
da91309e | 148 | |
b1beed72 YN |
149 | cpu = (node == NUMA_NO_NODE) ? |
150 | cpumask_nth(i, cpu_online_mask) : | |
151 | sched_numa_find_nth_cpu(cpu_online_mask, i, node); | |
152 | ||
153 | WARN_ON(cpu >= nr_cpu_ids); | |
154 | return cpu; | |
da91309e | 155 | } |
f36963c9 | 156 | EXPORT_SYMBOL(cpumask_local_spread); |
46a87b38 PT |
157 | |
158 | static DEFINE_PER_CPU(int, distribute_cpu_mask_prev); | |
159 | ||
160 | /** | |
dcb60f9c RD |
161 | * cpumask_any_and_distribute - Return an arbitrary cpu within src1p & src2p. |
162 | * @src1p: first &cpumask for intersection | |
163 | * @src2p: second &cpumask for intersection | |
46a87b38 PT |
164 | * |
165 | * Iterated calls using the same srcp1 and srcp2 will be distributed within | |
166 | * their intersection. | |
167 | * | |
168 | * Returns >= nr_cpu_ids if the intersection is empty. | |
169 | */ | |
8b6b795d | 170 | unsigned int cpumask_any_and_distribute(const struct cpumask *src1p, |
46a87b38 PT |
171 | const struct cpumask *src2p) |
172 | { | |
8b6b795d | 173 | unsigned int next, prev; |
46a87b38 PT |
174 | |
175 | /* NOTE: our first selection will skip 0. */ | |
176 | prev = __this_cpu_read(distribute_cpu_mask_prev); | |
177 | ||
6cc18331 YN |
178 | next = find_next_and_bit_wrap(cpumask_bits(src1p), cpumask_bits(src2p), |
179 | nr_cpumask_bits, prev + 1); | |
46a87b38 PT |
180 | if (next < nr_cpu_ids) |
181 | __this_cpu_write(distribute_cpu_mask_prev, next); | |
182 | ||
183 | return next; | |
184 | } | |
185 | EXPORT_SYMBOL(cpumask_any_and_distribute); | |
14e292f8 | 186 | |
8b6b795d | 187 | unsigned int cpumask_any_distribute(const struct cpumask *srcp) |
14e292f8 | 188 | { |
8b6b795d | 189 | unsigned int next, prev; |
14e292f8 PZ |
190 | |
191 | /* NOTE: our first selection will skip 0. */ | |
192 | prev = __this_cpu_read(distribute_cpu_mask_prev); | |
6cc18331 | 193 | next = find_next_bit_wrap(cpumask_bits(srcp), nr_cpumask_bits, prev + 1); |
14e292f8 PZ |
194 | if (next < nr_cpu_ids) |
195 | __this_cpu_write(distribute_cpu_mask_prev, next); | |
196 | ||
197 | return next; | |
198 | } | |
199 | EXPORT_SYMBOL(cpumask_any_distribute); |