1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_CPUSET_H
3 #define _LINUX_CPUSET_H
7 * Copyright (C) 2003 BULL SA
8 * Copyright (C) 2004-2006 Silicon Graphics, Inc.
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>
18 #include <linux/mmu_context.h>
19 #include <linux/jump_label.h>
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).
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;
39 static inline bool cpusets_enabled(void)
41 return static_branch_unlikely(&cpusets_enabled_key);
44 static inline void cpuset_inc(void)
46 static_branch_inc_cpuslocked(&cpusets_pre_enable_key);
47 static_branch_inc_cpuslocked(&cpusets_enabled_key);
50 static inline void cpuset_dec(void)
52 static_branch_dec_cpuslocked(&cpusets_enabled_key);
53 static_branch_dec_cpuslocked(&cpusets_pre_enable_key);
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
64 static inline bool cpusets_insane_config(void)
66 return static_branch_unlikely(&cpusets_insane_config_key);
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);
85 extern bool cpuset_node_allowed(int node, gfp_t gfp_mask);
87 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
89 return cpuset_node_allowed(zone_to_nid(z), gfp_mask);
92 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
94 if (cpusets_enabled())
95 return __cpuset_zone_allowed(z, gfp_mask);
99 extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
100 const struct task_struct *tsk2);
102 #define cpuset_memory_pressure_bump() \
104 if (cpuset_memory_pressure_enabled) \
105 __cpuset_memory_pressure_bump(); \
107 extern int cpuset_memory_pressure_enabled;
108 extern void __cpuset_memory_pressure_bump(void);
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);
115 extern int cpuset_mem_spread_node(void);
116 extern int cpuset_slab_spread_node(void);
118 static inline int cpuset_do_page_mem_spread(void)
120 return task_spread_page(current);
123 static inline int cpuset_do_slab_mem_spread(void)
125 return task_spread_slab(current);
128 extern bool current_cpuset_is_being_rebound(void);
130 extern void rebuild_sched_domains(void);
132 extern void cpuset_print_current_mems_allowed(void);
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.
141 static inline unsigned int read_mems_allowed_begin(void)
143 if (!static_branch_unlikely(&cpusets_pre_enable_key))
146 return read_seqcount_begin(¤t->mems_allowed_seq);
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
155 static inline bool read_mems_allowed_retry(unsigned int seq)
157 if (!static_branch_unlikely(&cpusets_enabled_key))
160 return read_seqcount_retry(¤t->mems_allowed_seq, seq);
163 static inline void set_mems_allowed(nodemask_t nodemask)
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);
176 #else /* !CONFIG_CPUSETS */
178 static inline bool cpusets_enabled(void) { return false; }
180 static inline bool cpusets_insane_config(void) { return false; }
182 static inline int cpuset_init(void) { return 0; }
183 static inline void cpuset_init_smp(void) {}
185 static inline void cpuset_force_rebuild(void) { }
187 static inline void cpuset_update_active_cpus(void)
189 partition_sched_domains(1, NULL, NULL);
192 static inline void cpuset_wait_for_hotplug(void) { }
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) { }
199 static inline void cpuset_cpus_allowed(struct task_struct *p,
200 struct cpumask *mask)
202 cpumask_copy(mask, task_cpu_possible_mask(p));
205 static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p)
210 static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
212 return node_possible_map;
215 #define cpuset_current_mems_allowed (node_states[N_MEMORY])
216 static inline void cpuset_init_current_mems_allowed(void) {}
218 static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
223 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
228 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
233 static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
234 const struct task_struct *tsk2)
239 static inline void cpuset_memory_pressure_bump(void) {}
241 static inline void cpuset_task_status_allowed(struct seq_file *m,
242 struct task_struct *task)
246 static inline int cpuset_mem_spread_node(void)
251 static inline int cpuset_slab_spread_node(void)
256 static inline int cpuset_do_page_mem_spread(void)
261 static inline int cpuset_do_slab_mem_spread(void)
266 static inline bool current_cpuset_is_being_rebound(void)
271 static inline void rebuild_sched_domains(void)
273 partition_sched_domains(1, NULL, NULL);
276 static inline void cpuset_print_current_mems_allowed(void)
280 static inline void set_mems_allowed(nodemask_t nodemask)
284 static inline unsigned int read_mems_allowed_begin(void)
289 static inline bool read_mems_allowed_retry(unsigned int seq)
294 #endif /* !CONFIG_CPUSETS */
296 #endif /* _LINUX_CPUSET_H */