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 int __first_cpu(const cpumask_t *srcp) 9 { 10 return min_t(int, NR_CPUS, find_first_bit(srcp->bits, NR_CPUS)); 11 } 12 EXPORT_SYMBOL(__first_cpu); 13 14 int __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 } 18 EXPORT_SYMBOL(__next_cpu); 19 20 #if NR_CPUS > 64 21 int __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 } 26 EXPORT_SYMBOL(__next_cpu_nr); 27 #endif 28 29 /** 30 * cpumask_next_and - get the next cpu in *src1p & *src2p 31 * @n: the cpu prior to the place to search (ie. return will be > @n) 32 * @src1p: the first cpumask pointer 33 * @src2p: the second cpumask pointer 34 * 35 * Returns >= nr_cpu_ids if no further cpus set in both. 36 */ 37 int cpumask_next_and(int n, const struct cpumask *src1p, 38 const struct cpumask *src2p) 39 { 40 while ((n = cpumask_next(n, src1p)) < nr_cpu_ids) 41 if (cpumask_test_cpu(n, src2p)) 42 break; 43 return n; 44 } 45 EXPORT_SYMBOL(cpumask_next_and); 46 47 /** 48 * cpumask_any_but - return a "random" in a cpumask, but not this one. 49 * @mask: the cpumask to search 50 * @cpu: the cpu to ignore. 51 * 52 * Often used to find any cpu but smp_processor_id() in a mask. 53 * Returns >= nr_cpu_ids if no cpus set. 54 */ 55 int cpumask_any_but(const struct cpumask *mask, unsigned int cpu) 56 { 57 unsigned int i; 58 59 cpumask_check(cpu); 60 for_each_cpu(i, mask) 61 if (i != cpu) 62 break; 63 return i; 64 } 65 66 /* These are not inline because of header tangles. */ 67 #ifdef CONFIG_CPUMASK_OFFSTACK 68 /** 69 * alloc_cpumask_var_node - allocate a struct cpumask on a given node 70 * @mask: pointer to cpumask_var_t where the cpumask is returned 71 * @flags: GFP_ flags 72 * 73 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is 74 * a nop returning a constant 1 (in <linux/cpumask.h>) 75 * Returns TRUE if memory allocation succeeded, FALSE otherwise. 76 * 77 * In addition, mask will be NULL if this fails. Note that gcc is 78 * usually smart enough to know that mask can never be NULL if 79 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case 80 * too. 81 */ 82 bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) 83 { 84 *mask = kmalloc_node(cpumask_size(), flags, node); 85 86 #ifdef CONFIG_DEBUG_PER_CPU_MAPS 87 if (!*mask) { 88 printk(KERN_ERR "=> alloc_cpumask_var: failed!\n"); 89 dump_stack(); 90 } 91 #endif 92 /* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */ 93 if (*mask) { 94 unsigned char *ptr = (unsigned char *)cpumask_bits(*mask); 95 unsigned int tail; 96 tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long); 97 memset(ptr + cpumask_size() - tail, 0, tail); 98 } 99 100 return *mask != NULL; 101 } 102 EXPORT_SYMBOL(alloc_cpumask_var_node); 103 104 bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) 105 { 106 return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node); 107 } 108 EXPORT_SYMBOL(zalloc_cpumask_var_node); 109 110 /** 111 * alloc_cpumask_var - allocate a struct cpumask 112 * @mask: pointer to cpumask_var_t where the cpumask is returned 113 * @flags: GFP_ flags 114 * 115 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is 116 * a nop returning a constant 1 (in <linux/cpumask.h>). 117 * 118 * See alloc_cpumask_var_node. 119 */ 120 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) 121 { 122 return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE); 123 } 124 EXPORT_SYMBOL(alloc_cpumask_var); 125 126 bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) 127 { 128 return alloc_cpumask_var(mask, flags | __GFP_ZERO); 129 } 130 EXPORT_SYMBOL(zalloc_cpumask_var); 131 132 /** 133 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena. 134 * @mask: pointer to cpumask_var_t where the cpumask is returned 135 * 136 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is 137 * a nop (in <linux/cpumask.h>). 138 * Either returns an allocated (zero-filled) cpumask, or causes the 139 * system to panic. 140 */ 141 void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask) 142 { 143 *mask = memblock_virt_alloc(cpumask_size(), 0); 144 } 145 146 /** 147 * free_cpumask_var - frees memory allocated for a struct cpumask. 148 * @mask: cpumask to free 149 * 150 * This is safe on a NULL mask. 151 */ 152 void free_cpumask_var(cpumask_var_t mask) 153 { 154 kfree(mask); 155 } 156 EXPORT_SYMBOL(free_cpumask_var); 157 158 /** 159 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var 160 * @mask: cpumask to free 161 */ 162 void __init free_bootmem_cpumask_var(cpumask_var_t mask) 163 { 164 memblock_free_early(__pa(mask), cpumask_size()); 165 } 166 #endif 167 168 /** 169 * cpumask_set_cpu_local_first - set i'th cpu with local numa cpu's first 170 * 171 * @i: index number 172 * @numa_node: local numa_node 173 * @dstp: cpumask with the relevant cpu bit set according to the policy 174 * 175 * This function sets the cpumask according to a numa aware policy. 176 * cpumask could be used as an affinity hint for the IRQ related to a 177 * queue. When the policy is to spread queues across cores - local cores 178 * first. 179 * 180 * Returns 0 on success, -ENOMEM for no memory, and -EAGAIN when failed to set 181 * the cpu bit and need to re-call the function. 182 */ 183 int cpumask_set_cpu_local_first(int i, int numa_node, cpumask_t *dstp) 184 { 185 cpumask_var_t mask; 186 int cpu; 187 int ret = 0; 188 189 if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) 190 return -ENOMEM; 191 192 i %= num_online_cpus(); 193 194 if (numa_node == -1 || !cpumask_of_node(numa_node)) { 195 /* Use all online cpu's for non numa aware system */ 196 cpumask_copy(mask, cpu_online_mask); 197 } else { 198 int n; 199 200 cpumask_and(mask, 201 cpumask_of_node(numa_node), cpu_online_mask); 202 203 n = cpumask_weight(mask); 204 if (i >= n) { 205 i -= n; 206 207 /* If index > number of local cpu's, mask out local 208 * cpu's 209 */ 210 cpumask_andnot(mask, cpu_online_mask, mask); 211 } 212 } 213 214 for_each_cpu(cpu, mask) { 215 if (--i < 0) 216 goto out; 217 } 218 219 ret = -EAGAIN; 220 221 out: 222 free_cpumask_var(mask); 223 224 if (!ret) 225 cpumask_set_cpu(cpu, dstp); 226 227 return ret; 228 } 229 EXPORT_SYMBOL(cpumask_set_cpu_local_first); 230