1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_CPUSET_H 3 #define _LINUX_CPUSET_H 4 /* 5 * cpuset interface 6 * 7 * Copyright (C) 2003 BULL SA 8 * Copyright (C) 2004-2006 Silicon Graphics, Inc. 9 * 10 */ 11 12 #include <linux/sched.h> 13 #include <linux/sched/topology.h> 14 #include <linux/sched/task.h> 15 #include <linux/cpumask.h> 16 #include <linux/nodemask.h> 17 #include <linux/mm.h> 18 #include <linux/mmu_context.h> 19 #include <linux/jump_label.h> 20 21 #ifdef CONFIG_CPUSETS 22 23 /* 24 * Static branch rewrites can happen in an arbitrary order for a given 25 * key. In code paths where we need to loop with read_mems_allowed_begin() and 26 * read_mems_allowed_retry() to get a consistent view of mems_allowed, we need 27 * to ensure that begin() always gets rewritten before retry() in the 28 * disabled -> enabled transition. If not, then if local irqs are disabled 29 * around the loop, we can deadlock since retry() would always be 30 * comparing the latest value of the mems_allowed seqcount against 0 as 31 * begin() still would see cpusets_enabled() as false. The enabled -> disabled 32 * transition should happen in reverse order for the same reasons (want to stop 33 * looking at real value of mems_allowed.sequence in retry() first). 34 */ 35 extern struct static_key_false cpusets_pre_enable_key; 36 extern struct static_key_false cpusets_enabled_key; 37 extern struct static_key_false cpusets_insane_config_key; 38 39 static inline bool cpusets_enabled(void) 40 { 41 return static_branch_unlikely(&cpusets_enabled_key); 42 } 43 44 static inline void cpuset_inc(void) 45 { 46 static_branch_inc_cpuslocked(&cpusets_pre_enable_key); 47 static_branch_inc_cpuslocked(&cpusets_enabled_key); 48 } 49 50 static inline void cpuset_dec(void) 51 { 52 static_branch_dec_cpuslocked(&cpusets_enabled_key); 53 static_branch_dec_cpuslocked(&cpusets_pre_enable_key); 54 } 55 56 /* 57 * This will get enabled whenever a cpuset configuration is considered 58 * unsupportable in general. E.g. movable only node which cannot satisfy 59 * any non movable allocations (see update_nodemask). Page allocator 60 * needs to make additional checks for those configurations and this 61 * check is meant to guard those checks without any overhead for sane 62 * configurations. 63 */ 64 static inline bool cpusets_insane_config(void) 65 { 66 return static_branch_unlikely(&cpusets_insane_config_key); 67 } 68 69 extern int cpuset_init(void); 70 extern void cpuset_init_smp(void); 71 extern void cpuset_force_rebuild(void); 72 extern void cpuset_update_active_cpus(void); 73 extern void cpuset_wait_for_hotplug(void); 74 extern void cpuset_read_lock(void); 75 extern void cpuset_read_unlock(void); 76 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask); 77 extern bool cpuset_cpus_allowed_fallback(struct task_struct *p); 78 extern nodemask_t cpuset_mems_allowed(struct task_struct *p); 79 #define cpuset_current_mems_allowed (current->mems_allowed) 80 void cpuset_init_current_mems_allowed(void); 81 int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask); 82 83 extern bool __cpuset_node_allowed(int node, gfp_t gfp_mask); 84 85 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask) 86 { 87 if (cpusets_enabled()) 88 return __cpuset_node_allowed(node, gfp_mask); 89 return true; 90 } 91 92 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 93 { 94 return __cpuset_node_allowed(zone_to_nid(z), gfp_mask); 95 } 96 97 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 98 { 99 if (cpusets_enabled()) 100 return __cpuset_zone_allowed(z, gfp_mask); 101 return true; 102 } 103 104 extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, 105 const struct task_struct *tsk2); 106 107 #define cpuset_memory_pressure_bump() \ 108 do { \ 109 if (cpuset_memory_pressure_enabled) \ 110 __cpuset_memory_pressure_bump(); \ 111 } while (0) 112 extern int cpuset_memory_pressure_enabled; 113 extern void __cpuset_memory_pressure_bump(void); 114 115 extern void cpuset_task_status_allowed(struct seq_file *m, 116 struct task_struct *task); 117 extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, 118 struct pid *pid, struct task_struct *tsk); 119 120 extern int cpuset_mem_spread_node(void); 121 extern int cpuset_slab_spread_node(void); 122 123 static inline int cpuset_do_page_mem_spread(void) 124 { 125 return task_spread_page(current); 126 } 127 128 static inline int cpuset_do_slab_mem_spread(void) 129 { 130 return task_spread_slab(current); 131 } 132 133 extern bool current_cpuset_is_being_rebound(void); 134 135 extern void rebuild_sched_domains(void); 136 137 extern void cpuset_print_current_mems_allowed(void); 138 139 /* 140 * read_mems_allowed_begin is required when making decisions involving 141 * mems_allowed such as during page allocation. mems_allowed can be updated in 142 * parallel and depending on the new value an operation can fail potentially 143 * causing process failure. A retry loop with read_mems_allowed_begin and 144 * read_mems_allowed_retry prevents these artificial failures. 145 */ 146 static inline unsigned int read_mems_allowed_begin(void) 147 { 148 if (!static_branch_unlikely(&cpusets_pre_enable_key)) 149 return 0; 150 151 return read_seqcount_begin(¤t->mems_allowed_seq); 152 } 153 154 /* 155 * If this returns true, the operation that took place after 156 * read_mems_allowed_begin may have failed artificially due to a concurrent 157 * update of mems_allowed. It is up to the caller to retry the operation if 158 * appropriate. 159 */ 160 static inline bool read_mems_allowed_retry(unsigned int seq) 161 { 162 if (!static_branch_unlikely(&cpusets_enabled_key)) 163 return false; 164 165 return read_seqcount_retry(¤t->mems_allowed_seq, seq); 166 } 167 168 static inline void set_mems_allowed(nodemask_t nodemask) 169 { 170 unsigned long flags; 171 172 task_lock(current); 173 local_irq_save(flags); 174 write_seqcount_begin(¤t->mems_allowed_seq); 175 current->mems_allowed = nodemask; 176 write_seqcount_end(¤t->mems_allowed_seq); 177 local_irq_restore(flags); 178 task_unlock(current); 179 } 180 181 #else /* !CONFIG_CPUSETS */ 182 183 static inline bool cpusets_enabled(void) { return false; } 184 185 static inline bool cpusets_insane_config(void) { return false; } 186 187 static inline int cpuset_init(void) { return 0; } 188 static inline void cpuset_init_smp(void) {} 189 190 static inline void cpuset_force_rebuild(void) { } 191 192 static inline void cpuset_update_active_cpus(void) 193 { 194 partition_sched_domains(1, NULL, NULL); 195 } 196 197 static inline void cpuset_wait_for_hotplug(void) { } 198 199 static inline void cpuset_read_lock(void) { } 200 static inline void cpuset_read_unlock(void) { } 201 202 static inline void cpuset_cpus_allowed(struct task_struct *p, 203 struct cpumask *mask) 204 { 205 cpumask_copy(mask, task_cpu_possible_mask(p)); 206 } 207 208 static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p) 209 { 210 return false; 211 } 212 213 static inline nodemask_t cpuset_mems_allowed(struct task_struct *p) 214 { 215 return node_possible_map; 216 } 217 218 #define cpuset_current_mems_allowed (node_states[N_MEMORY]) 219 static inline void cpuset_init_current_mems_allowed(void) {} 220 221 static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask) 222 { 223 return 1; 224 } 225 226 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask) 227 { 228 return true; 229 } 230 231 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 232 { 233 return true; 234 } 235 236 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 237 { 238 return true; 239 } 240 241 static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, 242 const struct task_struct *tsk2) 243 { 244 return 1; 245 } 246 247 static inline void cpuset_memory_pressure_bump(void) {} 248 249 static inline void cpuset_task_status_allowed(struct seq_file *m, 250 struct task_struct *task) 251 { 252 } 253 254 static inline int cpuset_mem_spread_node(void) 255 { 256 return 0; 257 } 258 259 static inline int cpuset_slab_spread_node(void) 260 { 261 return 0; 262 } 263 264 static inline int cpuset_do_page_mem_spread(void) 265 { 266 return 0; 267 } 268 269 static inline int cpuset_do_slab_mem_spread(void) 270 { 271 return 0; 272 } 273 274 static inline bool current_cpuset_is_being_rebound(void) 275 { 276 return false; 277 } 278 279 static inline void rebuild_sched_domains(void) 280 { 281 partition_sched_domains(1, NULL, NULL); 282 } 283 284 static inline void cpuset_print_current_mems_allowed(void) 285 { 286 } 287 288 static inline void set_mems_allowed(nodemask_t nodemask) 289 { 290 } 291 292 static inline unsigned int read_mems_allowed_begin(void) 293 { 294 return 0; 295 } 296 297 static inline bool read_mems_allowed_retry(unsigned int seq) 298 { 299 return false; 300 } 301 302 #endif /* !CONFIG_CPUSETS */ 303 304 #endif /* _LINUX_CPUSET_H */ 305