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 inc_dl_tasks_cs(struct task_struct *task); 74 extern void dec_dl_tasks_cs(struct task_struct *task); 75 extern void cpuset_lock(void); 76 extern void cpuset_unlock(void); 77 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask); 78 extern bool cpuset_cpus_allowed_fallback(struct task_struct *p); 79 extern bool cpuset_cpu_is_isolated(int cpu); 80 extern nodemask_t cpuset_mems_allowed(struct task_struct *p); 81 #define cpuset_current_mems_allowed (current->mems_allowed) 82 void cpuset_init_current_mems_allowed(void); 83 int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask); 84 85 extern bool cpuset_node_allowed(int node, gfp_t gfp_mask); 86 87 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 88 { 89 return cpuset_node_allowed(zone_to_nid(z), gfp_mask); 90 } 91 92 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 93 { 94 if (cpusets_enabled()) 95 return __cpuset_zone_allowed(z, gfp_mask); 96 return true; 97 } 98 99 extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, 100 const struct task_struct *tsk2); 101 102 #ifdef CONFIG_CPUSETS_V1 103 #define cpuset_memory_pressure_bump() \ 104 do { \ 105 if (cpuset_memory_pressure_enabled) \ 106 __cpuset_memory_pressure_bump(); \ 107 } while (0) 108 extern int cpuset_memory_pressure_enabled; 109 extern void __cpuset_memory_pressure_bump(void); 110 #else 111 static inline void cpuset_memory_pressure_bump(void) { } 112 #endif 113 114 extern void cpuset_task_status_allowed(struct seq_file *m, 115 struct task_struct *task); 116 extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, 117 struct pid *pid, struct task_struct *tsk); 118 119 extern int cpuset_mem_spread_node(void); 120 121 static inline int cpuset_do_page_mem_spread(void) 122 { 123 return task_spread_page(current); 124 } 125 126 extern bool current_cpuset_is_being_rebound(void); 127 128 extern void dl_rebuild_rd_accounting(void); 129 extern void rebuild_sched_domains(void); 130 131 extern void cpuset_print_current_mems_allowed(void); 132 extern void cpuset_reset_sched_domains(void); 133 134 /* 135 * read_mems_allowed_begin is required when making decisions involving 136 * mems_allowed such as during page allocation. mems_allowed can be updated in 137 * parallel and depending on the new value an operation can fail potentially 138 * causing process failure. A retry loop with read_mems_allowed_begin and 139 * read_mems_allowed_retry prevents these artificial failures. 140 */ 141 static inline unsigned int read_mems_allowed_begin(void) 142 { 143 if (!static_branch_unlikely(&cpusets_pre_enable_key)) 144 return 0; 145 146 return read_seqcount_begin(¤t->mems_allowed_seq); 147 } 148 149 /* 150 * If this returns true, the operation that took place after 151 * read_mems_allowed_begin may have failed artificially due to a concurrent 152 * update of mems_allowed. It is up to the caller to retry the operation if 153 * appropriate. 154 */ 155 static inline bool read_mems_allowed_retry(unsigned int seq) 156 { 157 if (!static_branch_unlikely(&cpusets_enabled_key)) 158 return false; 159 160 return read_seqcount_retry(¤t->mems_allowed_seq, seq); 161 } 162 163 static inline void set_mems_allowed(nodemask_t nodemask) 164 { 165 unsigned long flags; 166 167 task_lock(current); 168 local_irq_save(flags); 169 write_seqcount_begin(¤t->mems_allowed_seq); 170 current->mems_allowed = nodemask; 171 write_seqcount_end(¤t->mems_allowed_seq); 172 local_irq_restore(flags); 173 task_unlock(current); 174 } 175 176 #else /* !CONFIG_CPUSETS */ 177 178 static inline bool cpusets_enabled(void) { return false; } 179 180 static inline bool cpusets_insane_config(void) { return false; } 181 182 static inline int cpuset_init(void) { return 0; } 183 static inline void cpuset_init_smp(void) {} 184 185 static inline void cpuset_force_rebuild(void) { } 186 187 static inline void cpuset_update_active_cpus(void) 188 { 189 partition_sched_domains(1, NULL, NULL); 190 } 191 192 static inline void inc_dl_tasks_cs(struct task_struct *task) { } 193 static inline void dec_dl_tasks_cs(struct task_struct *task) { } 194 static inline void cpuset_lock(void) { } 195 static inline void cpuset_unlock(void) { } 196 197 static inline void cpuset_cpus_allowed(struct task_struct *p, 198 struct cpumask *mask) 199 { 200 cpumask_copy(mask, task_cpu_possible_mask(p)); 201 } 202 203 static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p) 204 { 205 return false; 206 } 207 208 static inline bool cpuset_cpu_is_isolated(int cpu) 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_zone_allowed(struct zone *z, 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 int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, 237 const struct task_struct *tsk2) 238 { 239 return 1; 240 } 241 242 static inline void cpuset_memory_pressure_bump(void) {} 243 244 static inline void cpuset_task_status_allowed(struct seq_file *m, 245 struct task_struct *task) 246 { 247 } 248 249 static inline int cpuset_mem_spread_node(void) 250 { 251 return 0; 252 } 253 254 static inline int cpuset_do_page_mem_spread(void) 255 { 256 return 0; 257 } 258 259 static inline bool current_cpuset_is_being_rebound(void) 260 { 261 return false; 262 } 263 264 static inline void dl_rebuild_rd_accounting(void) 265 { 266 } 267 268 static inline void rebuild_sched_domains(void) 269 { 270 partition_sched_domains(1, NULL, NULL); 271 } 272 273 static inline void cpuset_reset_sched_domains(void) 274 { 275 partition_sched_domains(1, NULL, NULL); 276 } 277 278 static inline void cpuset_print_current_mems_allowed(void) 279 { 280 } 281 282 static inline void set_mems_allowed(nodemask_t nodemask) 283 { 284 } 285 286 static inline unsigned int read_mems_allowed_begin(void) 287 { 288 return 0; 289 } 290 291 static inline bool read_mems_allowed_retry(unsigned int seq) 292 { 293 return false; 294 } 295 296 #endif /* !CONFIG_CPUSETS */ 297 298 #endif /* _LINUX_CPUSET_H */ 299