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 inc_dl_tasks_cs(struct task_struct *task); 75 extern void dec_dl_tasks_cs(struct task_struct *task); 76 extern void cpuset_lock(void); 77 extern void cpuset_unlock(void); 78 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask); 79 extern bool cpuset_cpus_allowed_fallback(struct task_struct *p); 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 #define cpuset_memory_pressure_bump() \ 103 do { \ 104 if (cpuset_memory_pressure_enabled) \ 105 __cpuset_memory_pressure_bump(); \ 106 } while (0) 107 extern int cpuset_memory_pressure_enabled; 108 extern void __cpuset_memory_pressure_bump(void); 109 110 extern void cpuset_task_status_allowed(struct seq_file *m, 111 struct task_struct *task); 112 extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, 113 struct pid *pid, struct task_struct *tsk); 114 115 extern int cpuset_mem_spread_node(void); 116 extern int cpuset_slab_spread_node(void); 117 118 static inline int cpuset_do_page_mem_spread(void) 119 { 120 return task_spread_page(current); 121 } 122 123 static inline int cpuset_do_slab_mem_spread(void) 124 { 125 return task_spread_slab(current); 126 } 127 128 extern bool current_cpuset_is_being_rebound(void); 129 130 extern void rebuild_sched_domains(void); 131 132 extern void cpuset_print_current_mems_allowed(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 cpuset_wait_for_hotplug(void) { } 193 194 static inline void inc_dl_tasks_cs(struct task_struct *task) { } 195 static inline void dec_dl_tasks_cs(struct task_struct *task) { } 196 static inline void cpuset_lock(void) { } 197 static inline void cpuset_unlock(void) { } 198 199 static inline void cpuset_cpus_allowed(struct task_struct *p, 200 struct cpumask *mask) 201 { 202 cpumask_copy(mask, task_cpu_possible_mask(p)); 203 } 204 205 static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p) 206 { 207 return false; 208 } 209 210 static inline nodemask_t cpuset_mems_allowed(struct task_struct *p) 211 { 212 return node_possible_map; 213 } 214 215 #define cpuset_current_mems_allowed (node_states[N_MEMORY]) 216 static inline void cpuset_init_current_mems_allowed(void) {} 217 218 static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask) 219 { 220 return 1; 221 } 222 223 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 224 { 225 return true; 226 } 227 228 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 229 { 230 return true; 231 } 232 233 static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, 234 const struct task_struct *tsk2) 235 { 236 return 1; 237 } 238 239 static inline void cpuset_memory_pressure_bump(void) {} 240 241 static inline void cpuset_task_status_allowed(struct seq_file *m, 242 struct task_struct *task) 243 { 244 } 245 246 static inline int cpuset_mem_spread_node(void) 247 { 248 return 0; 249 } 250 251 static inline int cpuset_slab_spread_node(void) 252 { 253 return 0; 254 } 255 256 static inline int cpuset_do_page_mem_spread(void) 257 { 258 return 0; 259 } 260 261 static inline int cpuset_do_slab_mem_spread(void) 262 { 263 return 0; 264 } 265 266 static inline bool current_cpuset_is_being_rebound(void) 267 { 268 return false; 269 } 270 271 static inline void rebuild_sched_domains(void) 272 { 273 partition_sched_domains(1, NULL, NULL); 274 } 275 276 static inline void cpuset_print_current_mems_allowed(void) 277 { 278 } 279 280 static inline void set_mems_allowed(nodemask_t nodemask) 281 { 282 } 283 284 static inline unsigned int read_mems_allowed_begin(void) 285 { 286 return 0; 287 } 288 289 static inline bool read_mems_allowed_retry(unsigned int seq) 290 { 291 return false; 292 } 293 294 #endif /* !CONFIG_CPUSETS */ 295 296 #endif /* _LINUX_CPUSET_H */ 297