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 static inline bool cpusets_enabled(void)
39 return static_branch_unlikely(&cpusets_enabled_key);
42 static inline void cpuset_inc(void)
44 static_branch_inc_cpuslocked(&cpusets_pre_enable_key);
45 static_branch_inc_cpuslocked(&cpusets_enabled_key);
48 static inline void cpuset_dec(void)
50 static_branch_dec_cpuslocked(&cpusets_enabled_key);
51 static_branch_dec_cpuslocked(&cpusets_pre_enable_key);
54 extern int cpuset_init(void);
55 extern void cpuset_init_smp(void);
56 extern void cpuset_force_rebuild(void);
57 extern void cpuset_update_active_cpus(void);
58 extern void cpuset_wait_for_hotplug(void);
59 extern void inc_dl_tasks_cs(struct task_struct *task);
60 extern void dec_dl_tasks_cs(struct task_struct *task);
61 extern void cpuset_lock(void);
62 extern void cpuset_unlock(void);
63 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
64 extern bool cpuset_cpus_allowed_fallback(struct task_struct *p);
65 extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
66 #define cpuset_current_mems_allowed (current->mems_allowed)
67 void cpuset_init_current_mems_allowed(void);
68 int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
70 extern bool __cpuset_node_allowed(int node, gfp_t gfp_mask);
72 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
74 if (cpusets_enabled())
75 return __cpuset_node_allowed(node, gfp_mask);
79 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
81 return __cpuset_node_allowed(zone_to_nid(z), gfp_mask);
84 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
86 if (cpusets_enabled())
87 return __cpuset_zone_allowed(z, gfp_mask);
91 extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
92 const struct task_struct *tsk2);
94 #define cpuset_memory_pressure_bump() \
96 if (cpuset_memory_pressure_enabled) \
97 __cpuset_memory_pressure_bump(); \
99 extern int cpuset_memory_pressure_enabled;
100 extern void __cpuset_memory_pressure_bump(void);
102 extern void cpuset_task_status_allowed(struct seq_file *m,
103 struct task_struct *task);
104 extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
105 struct pid *pid, struct task_struct *tsk);
107 extern int cpuset_mem_spread_node(void);
108 extern int cpuset_slab_spread_node(void);
110 static inline int cpuset_do_page_mem_spread(void)
112 return task_spread_page(current);
115 static inline int cpuset_do_slab_mem_spread(void)
117 return task_spread_slab(current);
120 extern bool current_cpuset_is_being_rebound(void);
122 extern void rebuild_sched_domains(void);
124 extern void cpuset_print_current_mems_allowed(void);
127 * read_mems_allowed_begin is required when making decisions involving
128 * mems_allowed such as during page allocation. mems_allowed can be updated in
129 * parallel and depending on the new value an operation can fail potentially
130 * causing process failure. A retry loop with read_mems_allowed_begin and
131 * read_mems_allowed_retry prevents these artificial failures.
133 static inline unsigned int read_mems_allowed_begin(void)
135 if (!static_branch_unlikely(&cpusets_pre_enable_key))
138 return read_seqcount_begin(¤t->mems_allowed_seq);
142 * If this returns true, the operation that took place after
143 * read_mems_allowed_begin may have failed artificially due to a concurrent
144 * update of mems_allowed. It is up to the caller to retry the operation if
147 static inline bool read_mems_allowed_retry(unsigned int seq)
149 if (!static_branch_unlikely(&cpusets_enabled_key))
152 return read_seqcount_retry(¤t->mems_allowed_seq, seq);
155 static inline void set_mems_allowed(nodemask_t nodemask)
160 local_irq_save(flags);
161 write_seqcount_begin(¤t->mems_allowed_seq);
162 current->mems_allowed = nodemask;
163 write_seqcount_end(¤t->mems_allowed_seq);
164 local_irq_restore(flags);
165 task_unlock(current);
168 #else /* !CONFIG_CPUSETS */
170 static inline bool cpusets_enabled(void) { return false; }
172 static inline int cpuset_init(void) { return 0; }
173 static inline void cpuset_init_smp(void) {}
175 static inline void cpuset_force_rebuild(void) { }
177 static inline void cpuset_update_active_cpus(void)
179 partition_sched_domains(1, NULL, NULL);
182 static inline void cpuset_wait_for_hotplug(void) { }
184 static inline void inc_dl_tasks_cs(struct task_struct *task) { }
185 static inline void dec_dl_tasks_cs(struct task_struct *task) { }
186 static inline void cpuset_lock(void) { }
187 static inline void cpuset_unlock(void) { }
189 static inline void cpuset_cpus_allowed(struct task_struct *p,
190 struct cpumask *mask)
192 cpumask_copy(mask, task_cpu_possible_mask(p));
195 static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p)
200 static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
202 return node_possible_map;
205 #define cpuset_current_mems_allowed (node_states[N_MEMORY])
206 static inline void cpuset_init_current_mems_allowed(void) {}
208 static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
213 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
218 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
223 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
228 static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
229 const struct task_struct *tsk2)
234 static inline void cpuset_memory_pressure_bump(void) {}
236 static inline void cpuset_task_status_allowed(struct seq_file *m,
237 struct task_struct *task)
241 static inline int cpuset_mem_spread_node(void)
246 static inline int cpuset_slab_spread_node(void)
251 static inline int cpuset_do_page_mem_spread(void)
256 static inline int cpuset_do_slab_mem_spread(void)
261 static inline bool current_cpuset_is_being_rebound(void)
266 static inline void rebuild_sched_domains(void)
268 partition_sched_domains(1, NULL, NULL);
271 static inline void cpuset_print_current_mems_allowed(void)
275 static inline void set_mems_allowed(nodemask_t nodemask)
279 static inline unsigned int read_mems_allowed_begin(void)
284 static inline bool read_mems_allowed_retry(unsigned int seq)
289 #endif /* !CONFIG_CPUSETS */
291 #endif /* _LINUX_CPUSET_H */