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 struct cpumask tmp; 41 42 if (cpumask_and(&tmp, src1p, src2p)) 43 return cpumask_next(n, &tmp); 44 return nr_cpu_ids; 45 } 46 EXPORT_SYMBOL(cpumask_next_and); 47 48 /** 49 * cpumask_any_but - return a "random" in a cpumask, but not this one. 50 * @mask: the cpumask to search 51 * @cpu: the cpu to ignore. 52 * 53 * Often used to find any cpu but smp_processor_id() in a mask. 54 * Returns >= nr_cpu_ids if no cpus set. 55 */ 56 int cpumask_any_but(const struct cpumask *mask, unsigned int cpu) 57 { 58 unsigned int i; 59 60 cpumask_check(cpu); 61 for_each_cpu(i, mask) 62 if (i != cpu) 63 break; 64 return i; 65 } 66 67 /* These are not inline because of header tangles. */ 68 #ifdef CONFIG_CPUMASK_OFFSTACK 69 /** 70 * alloc_cpumask_var_node - allocate a struct cpumask on a given node 71 * @mask: pointer to cpumask_var_t where the cpumask is returned 72 * @flags: GFP_ flags 73 * 74 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is 75 * a nop returning a constant 1 (in <linux/cpumask.h>) 76 * Returns TRUE if memory allocation succeeded, FALSE otherwise. 77 * 78 * In addition, mask will be NULL if this fails. Note that gcc is 79 * usually smart enough to know that mask can never be NULL if 80 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case 81 * too. 82 */ 83 bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) 84 { 85 *mask = kmalloc_node(cpumask_size(), flags, node); 86 87 #ifdef CONFIG_DEBUG_PER_CPU_MAPS 88 if (!*mask) { 89 printk(KERN_ERR "=> alloc_cpumask_var: failed!\n"); 90 dump_stack(); 91 } 92 #endif 93 /* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */ 94 if (*mask) { 95 unsigned char *ptr = (unsigned char *)cpumask_bits(*mask); 96 unsigned int tail; 97 tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long); 98 memset(ptr + cpumask_size() - tail, 0, tail); 99 } 100 101 return *mask != NULL; 102 } 103 EXPORT_SYMBOL(alloc_cpumask_var_node); 104 105 bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) 106 { 107 return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node); 108 } 109 EXPORT_SYMBOL(zalloc_cpumask_var_node); 110 111 /** 112 * alloc_cpumask_var - allocate a struct cpumask 113 * @mask: pointer to cpumask_var_t where the cpumask is returned 114 * @flags: GFP_ flags 115 * 116 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is 117 * a nop returning a constant 1 (in <linux/cpumask.h>). 118 * 119 * See alloc_cpumask_var_node. 120 */ 121 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) 122 { 123 return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE); 124 } 125 EXPORT_SYMBOL(alloc_cpumask_var); 126 127 bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) 128 { 129 return alloc_cpumask_var(mask, flags | __GFP_ZERO); 130 } 131 EXPORT_SYMBOL(zalloc_cpumask_var); 132 133 /** 134 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena. 135 * @mask: pointer to cpumask_var_t where the cpumask is returned 136 * 137 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is 138 * a nop (in <linux/cpumask.h>). 139 * Either returns an allocated (zero-filled) cpumask, or causes the 140 * system to panic. 141 */ 142 void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask) 143 { 144 *mask = memblock_virt_alloc(cpumask_size(), 0); 145 } 146 147 /** 148 * free_cpumask_var - frees memory allocated for a struct cpumask. 149 * @mask: cpumask to free 150 * 151 * This is safe on a NULL mask. 152 */ 153 void free_cpumask_var(cpumask_var_t mask) 154 { 155 kfree(mask); 156 } 157 EXPORT_SYMBOL(free_cpumask_var); 158 159 /** 160 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var 161 * @mask: cpumask to free 162 */ 163 void __init free_bootmem_cpumask_var(cpumask_var_t mask) 164 { 165 memblock_free_early(__pa(mask), cpumask_size()); 166 } 167 #endif 168 169 /** 170 * cpumask_set_cpu_local_first - set i'th cpu with local numa cpu's first 171 * 172 * @i: index number 173 * @numa_node: local numa_node 174 * @dstp: cpumask with the relevant cpu bit set according to the policy 175 * 176 * This function sets the cpumask according to a numa aware policy. 177 * cpumask could be used as an affinity hint for the IRQ related to a 178 * queue. When the policy is to spread queues across cores - local cores 179 * first. 180 * 181 * Returns 0 on success, -ENOMEM for no memory, and -EAGAIN when failed to set 182 * the cpu bit and need to re-call the function. 183 */ 184 int cpumask_set_cpu_local_first(int i, int numa_node, cpumask_t *dstp) 185 { 186 cpumask_var_t mask; 187 int cpu; 188 int ret = 0; 189 190 if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) 191 return -ENOMEM; 192 193 i %= num_online_cpus(); 194 195 if (numa_node == -1 || !cpumask_of_node(numa_node)) { 196 /* Use all online cpu's for non numa aware system */ 197 cpumask_copy(mask, cpu_online_mask); 198 } else { 199 int n; 200 201 cpumask_and(mask, 202 cpumask_of_node(numa_node), cpu_online_mask); 203 204 n = cpumask_weight(mask); 205 if (i >= n) { 206 i -= n; 207 208 /* If index > number of local cpu's, mask out local 209 * cpu's 210 */ 211 cpumask_andnot(mask, cpu_online_mask, mask); 212 } 213 } 214 215 for_each_cpu(cpu, mask) { 216 if (--i < 0) 217 goto out; 218 } 219 220 ret = -EAGAIN; 221 222 out: 223 free_cpumask_var(mask); 224 225 if (!ret) 226 cpumask_set_cpu(cpu, dstp); 227 228 return ret; 229 } 230 EXPORT_SYMBOL(cpumask_set_cpu_local_first); 231