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 */ 35extern struct static_key_false cpusets_pre_enable_key; 36extern struct static_key_false cpusets_enabled_key; 37extern struct static_key_false cpusets_insane_config_key; 38 39static inline bool cpusets_enabled(void) 40{ 41 return static_branch_unlikely(&cpusets_enabled_key); 42} 43 44static 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 50static 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 */ 64static inline bool cpusets_insane_config(void) 65{ 66 return static_branch_unlikely(&cpusets_insane_config_key); 67} 68 69extern int cpuset_init(void); 70extern void cpuset_init_smp(void); 71extern void cpuset_force_rebuild(void); 72extern void cpuset_update_active_cpus(void); 73extern void cpuset_wait_for_hotplug(void); 74extern void inc_dl_tasks_cs(struct task_struct *task); 75extern void dec_dl_tasks_cs(struct task_struct *task); 76extern void cpuset_lock(void); 77extern void cpuset_unlock(void); 78extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask); 79extern bool cpuset_cpus_allowed_fallback(struct task_struct *p); 80extern bool cpuset_cpu_is_isolated(int cpu); 81extern nodemask_t cpuset_mems_allowed(struct task_struct *p); 82#define cpuset_current_mems_allowed (current->mems_allowed) 83void cpuset_init_current_mems_allowed(void); 84int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask); 85 86extern bool cpuset_node_allowed(int node, gfp_t gfp_mask); 87 88static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 89{ 90 return cpuset_node_allowed(zone_to_nid(z), gfp_mask); 91} 92 93static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 94{ 95 if (cpusets_enabled()) 96 return __cpuset_zone_allowed(z, gfp_mask); 97 return true; 98} 99 100extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, 101 const struct task_struct *tsk2); 102 103#define cpuset_memory_pressure_bump() \ 104 do { \ 105 if (cpuset_memory_pressure_enabled) \ 106 __cpuset_memory_pressure_bump(); \ 107 } while (0) 108extern int cpuset_memory_pressure_enabled; 109extern void __cpuset_memory_pressure_bump(void); 110 111extern void cpuset_task_status_allowed(struct seq_file *m, 112 struct task_struct *task); 113extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, 114 struct pid *pid, struct task_struct *tsk); 115 116extern int cpuset_mem_spread_node(void); 117extern int cpuset_slab_spread_node(void); 118 119static inline int cpuset_do_page_mem_spread(void) 120{ 121 return task_spread_page(current); 122} 123 124extern bool current_cpuset_is_being_rebound(void); 125 126extern void rebuild_sched_domains(void); 127 128extern void cpuset_print_current_mems_allowed(void); 129 130/* 131 * read_mems_allowed_begin is required when making decisions involving 132 * mems_allowed such as during page allocation. mems_allowed can be updated in 133 * parallel and depending on the new value an operation can fail potentially 134 * causing process failure. A retry loop with read_mems_allowed_begin and 135 * read_mems_allowed_retry prevents these artificial failures. 136 */ 137static inline unsigned int read_mems_allowed_begin(void) 138{ 139 if (!static_branch_unlikely(&cpusets_pre_enable_key)) 140 return 0; 141 142 return read_seqcount_begin(¤t->mems_allowed_seq); 143} 144 145/* 146 * If this returns true, the operation that took place after 147 * read_mems_allowed_begin may have failed artificially due to a concurrent 148 * update of mems_allowed. It is up to the caller to retry the operation if 149 * appropriate. 150 */ 151static inline bool read_mems_allowed_retry(unsigned int seq) 152{ 153 if (!static_branch_unlikely(&cpusets_enabled_key)) 154 return false; 155 156 return read_seqcount_retry(¤t->mems_allowed_seq, seq); 157} 158 159static inline void set_mems_allowed(nodemask_t nodemask) 160{ 161 unsigned long flags; 162 163 task_lock(current); 164 local_irq_save(flags); 165 write_seqcount_begin(¤t->mems_allowed_seq); 166 current->mems_allowed = nodemask; 167 write_seqcount_end(¤t->mems_allowed_seq); 168 local_irq_restore(flags); 169 task_unlock(current); 170} 171 172#else /* !CONFIG_CPUSETS */ 173 174static inline bool cpusets_enabled(void) { return false; } 175 176static inline bool cpusets_insane_config(void) { return false; } 177 178static inline int cpuset_init(void) { return 0; } 179static inline void cpuset_init_smp(void) {} 180 181static inline void cpuset_force_rebuild(void) { } 182 183static inline void cpuset_update_active_cpus(void) 184{ 185 partition_sched_domains(1, NULL, NULL); 186} 187 188static inline void cpuset_wait_for_hotplug(void) { } 189 190static inline void inc_dl_tasks_cs(struct task_struct *task) { } 191static inline void dec_dl_tasks_cs(struct task_struct *task) { } 192static inline void cpuset_lock(void) { } 193static inline void cpuset_unlock(void) { } 194 195static inline void cpuset_cpus_allowed(struct task_struct *p, 196 struct cpumask *mask) 197{ 198 cpumask_copy(mask, task_cpu_possible_mask(p)); 199} 200 201static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p) 202{ 203 return false; 204} 205 206static inline bool cpuset_cpu_is_isolated(int cpu) 207{ 208 return false; 209} 210 211static inline nodemask_t cpuset_mems_allowed(struct task_struct *p) 212{ 213 return node_possible_map; 214} 215 216#define cpuset_current_mems_allowed (node_states[N_MEMORY]) 217static inline void cpuset_init_current_mems_allowed(void) {} 218 219static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask) 220{ 221 return 1; 222} 223 224static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 225{ 226 return true; 227} 228 229static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) 230{ 231 return true; 232} 233 234static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, 235 const struct task_struct *tsk2) 236{ 237 return 1; 238} 239 240static inline void cpuset_memory_pressure_bump(void) {} 241 242static inline void cpuset_task_status_allowed(struct seq_file *m, 243 struct task_struct *task) 244{ 245} 246 247static inline int cpuset_mem_spread_node(void) 248{ 249 return 0; 250} 251 252static inline int cpuset_slab_spread_node(void) 253{ 254 return 0; 255} 256 257static inline int cpuset_do_page_mem_spread(void) 258{ 259 return 0; 260} 261 262static inline bool current_cpuset_is_being_rebound(void) 263{ 264 return false; 265} 266 267static inline void rebuild_sched_domains(void) 268{ 269 partition_sched_domains(1, NULL, NULL); 270} 271 272static inline void cpuset_print_current_mems_allowed(void) 273{ 274} 275 276static inline void set_mems_allowed(nodemask_t nodemask) 277{ 278} 279 280static inline unsigned int read_mems_allowed_begin(void) 281{ 282 return 0; 283} 284 285static inline bool read_mems_allowed_retry(unsigned int seq) 286{ 287 return false; 288} 289 290#endif /* !CONFIG_CPUSETS */ 291 292#endif /* _LINUX_CPUSET_H */ 293