| 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 - get the next cpu in a cpumask |
| 12 | * @n: the cpu prior to the place to search (ie. return will be > @n) |
| 13 | * @srcp: the cpumask pointer |
| 14 | * |
| 15 | * Returns >= nr_cpu_ids if no further cpus set. |
| 16 | */ |
| 17 | unsigned int cpumask_next(int n, const struct cpumask *srcp) |
| 18 | { |
| 19 | /* -1 is a legal arg here. */ |
| 20 | if (n != -1) |
| 21 | cpumask_check(n); |
| 22 | return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1); |
| 23 | } |
| 24 | EXPORT_SYMBOL(cpumask_next); |
| 25 | |
| 26 | /** |
| 27 | * cpumask_next_and - get the next cpu in *src1p & *src2p |
| 28 | * @n: the cpu prior to the place to search (ie. return will be > @n) |
| 29 | * @src1p: the first cpumask pointer |
| 30 | * @src2p: the second cpumask pointer |
| 31 | * |
| 32 | * Returns >= nr_cpu_ids if no further cpus set in both. |
| 33 | */ |
| 34 | int cpumask_next_and(int n, const struct cpumask *src1p, |
| 35 | const struct cpumask *src2p) |
| 36 | { |
| 37 | /* -1 is a legal arg here. */ |
| 38 | if (n != -1) |
| 39 | cpumask_check(n); |
| 40 | return find_next_and_bit(cpumask_bits(src1p), cpumask_bits(src2p), |
| 41 | nr_cpumask_bits, n + 1); |
| 42 | } |
| 43 | EXPORT_SYMBOL(cpumask_next_and); |
| 44 | |
| 45 | /** |
| 46 | * cpumask_any_but - return a "random" in a cpumask, but not this one. |
| 47 | * @mask: the cpumask to search |
| 48 | * @cpu: the cpu to ignore. |
| 49 | * |
| 50 | * Often used to find any cpu but smp_processor_id() in a mask. |
| 51 | * Returns >= nr_cpu_ids if no cpus set. |
| 52 | */ |
| 53 | int cpumask_any_but(const struct cpumask *mask, unsigned int cpu) |
| 54 | { |
| 55 | unsigned int i; |
| 56 | |
| 57 | cpumask_check(cpu); |
| 58 | for_each_cpu(i, mask) |
| 59 | if (i != cpu) |
| 60 | break; |
| 61 | return i; |
| 62 | } |
| 63 | EXPORT_SYMBOL(cpumask_any_but); |
| 64 | |
| 65 | /** |
| 66 | * cpumask_next_wrap - helper to implement for_each_cpu_wrap |
| 67 | * @n: the cpu prior to the place to search |
| 68 | * @mask: the cpumask pointer |
| 69 | * @start: the start point of the iteration |
| 70 | * @wrap: assume @n crossing @start terminates the iteration |
| 71 | * |
| 72 | * Returns >= nr_cpu_ids on completion |
| 73 | * |
| 74 | * Note: the @wrap argument is required for the start condition when |
| 75 | * we cannot assume @start is set in @mask. |
| 76 | */ |
| 77 | int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap) |
| 78 | { |
| 79 | int next; |
| 80 | |
| 81 | again: |
| 82 | next = cpumask_next(n, mask); |
| 83 | |
| 84 | if (wrap && n < start && next >= start) { |
| 85 | return nr_cpumask_bits; |
| 86 | |
| 87 | } else if (next >= nr_cpumask_bits) { |
| 88 | wrap = true; |
| 89 | n = -1; |
| 90 | goto again; |
| 91 | } |
| 92 | |
| 93 | return next; |
| 94 | } |
| 95 | EXPORT_SYMBOL(cpumask_next_wrap); |
| 96 | |
| 97 | /* These are not inline because of header tangles. */ |
| 98 | #ifdef CONFIG_CPUMASK_OFFSTACK |
| 99 | /** |
| 100 | * alloc_cpumask_var_node - allocate a struct cpumask on a given node |
| 101 | * @mask: pointer to cpumask_var_t where the cpumask is returned |
| 102 | * @flags: GFP_ flags |
| 103 | * |
| 104 | * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is |
| 105 | * a nop returning a constant 1 (in <linux/cpumask.h>) |
| 106 | * Returns TRUE if memory allocation succeeded, FALSE otherwise. |
| 107 | * |
| 108 | * In addition, mask will be NULL if this fails. Note that gcc is |
| 109 | * usually smart enough to know that mask can never be NULL if |
| 110 | * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case |
| 111 | * too. |
| 112 | */ |
| 113 | bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) |
| 114 | { |
| 115 | *mask = kmalloc_node(cpumask_size(), flags, node); |
| 116 | |
| 117 | #ifdef CONFIG_DEBUG_PER_CPU_MAPS |
| 118 | if (!*mask) { |
| 119 | printk(KERN_ERR "=> alloc_cpumask_var: failed!\n"); |
| 120 | dump_stack(); |
| 121 | } |
| 122 | #endif |
| 123 | |
| 124 | return *mask != NULL; |
| 125 | } |
| 126 | EXPORT_SYMBOL(alloc_cpumask_var_node); |
| 127 | |
| 128 | bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) |
| 129 | { |
| 130 | return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node); |
| 131 | } |
| 132 | EXPORT_SYMBOL(zalloc_cpumask_var_node); |
| 133 | |
| 134 | /** |
| 135 | * alloc_cpumask_var - allocate a struct cpumask |
| 136 | * @mask: pointer to cpumask_var_t where the cpumask is returned |
| 137 | * @flags: GFP_ flags |
| 138 | * |
| 139 | * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is |
| 140 | * a nop returning a constant 1 (in <linux/cpumask.h>). |
| 141 | * |
| 142 | * See alloc_cpumask_var_node. |
| 143 | */ |
| 144 | bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) |
| 145 | { |
| 146 | return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE); |
| 147 | } |
| 148 | EXPORT_SYMBOL(alloc_cpumask_var); |
| 149 | |
| 150 | bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) |
| 151 | { |
| 152 | return alloc_cpumask_var(mask, flags | __GFP_ZERO); |
| 153 | } |
| 154 | EXPORT_SYMBOL(zalloc_cpumask_var); |
| 155 | |
| 156 | /** |
| 157 | * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena. |
| 158 | * @mask: pointer to cpumask_var_t where the cpumask is returned |
| 159 | * |
| 160 | * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is |
| 161 | * a nop (in <linux/cpumask.h>). |
| 162 | * Either returns an allocated (zero-filled) cpumask, or causes the |
| 163 | * system to panic. |
| 164 | */ |
| 165 | void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask) |
| 166 | { |
| 167 | *mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES); |
| 168 | if (!*mask) |
| 169 | panic("%s: Failed to allocate %u bytes\n", __func__, |
| 170 | cpumask_size()); |
| 171 | } |
| 172 | |
| 173 | /** |
| 174 | * free_cpumask_var - frees memory allocated for a struct cpumask. |
| 175 | * @mask: cpumask to free |
| 176 | * |
| 177 | * This is safe on a NULL mask. |
| 178 | */ |
| 179 | void free_cpumask_var(cpumask_var_t mask) |
| 180 | { |
| 181 | kfree(mask); |
| 182 | } |
| 183 | EXPORT_SYMBOL(free_cpumask_var); |
| 184 | |
| 185 | /** |
| 186 | * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var |
| 187 | * @mask: cpumask to free |
| 188 | */ |
| 189 | void __init free_bootmem_cpumask_var(cpumask_var_t mask) |
| 190 | { |
| 191 | memblock_free_early(__pa(mask), cpumask_size()); |
| 192 | } |
| 193 | #endif |
| 194 | |
| 195 | /** |
| 196 | * cpumask_local_spread - select the i'th cpu with local numa cpu's first |
| 197 | * @i: index number |
| 198 | * @node: local numa_node |
| 199 | * |
| 200 | * This function selects an online CPU according to a numa aware policy; |
| 201 | * local cpus are returned first, followed by non-local ones, then it |
| 202 | * wraps around. |
| 203 | * |
| 204 | * It's not very efficient, but useful for setup. |
| 205 | */ |
| 206 | unsigned int cpumask_local_spread(unsigned int i, int node) |
| 207 | { |
| 208 | int cpu; |
| 209 | |
| 210 | /* Wrap: we always want a cpu. */ |
| 211 | i %= num_online_cpus(); |
| 212 | |
| 213 | if (node == NUMA_NO_NODE) { |
| 214 | for_each_cpu(cpu, cpu_online_mask) |
| 215 | if (i-- == 0) |
| 216 | return cpu; |
| 217 | } else { |
| 218 | /* NUMA first. */ |
| 219 | for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask) |
| 220 | if (i-- == 0) |
| 221 | return cpu; |
| 222 | |
| 223 | for_each_cpu(cpu, cpu_online_mask) { |
| 224 | /* Skip NUMA nodes, done above. */ |
| 225 | if (cpumask_test_cpu(cpu, cpumask_of_node(node))) |
| 226 | continue; |
| 227 | |
| 228 | if (i-- == 0) |
| 229 | return cpu; |
| 230 | } |
| 231 | } |
| 232 | BUG(); |
| 233 | } |
| 234 | EXPORT_SYMBOL(cpumask_local_spread); |