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/jump_label.h>
23 * Static branch rewrites can happen in an arbitrary order for a given
24 * key. In code paths where we need to loop with read_mems_allowed_begin() and
25 * read_mems_allowed_retry() to get a consistent view of mems_allowed, we need
26 * to ensure that begin() always gets rewritten before retry() in the
27 * disabled -> enabled transition. If not, then if local irqs are disabled
28 * around the loop, we can deadlock since retry() would always be
29 * comparing the latest value of the mems_allowed seqcount against 0 as
30 * begin() still would see cpusets_enabled() as false. The enabled -> disabled
31 * transition should happen in reverse order for the same reasons (want to stop
32 * looking at real value of mems_allowed.sequence in retry() first).
34 extern struct static_key_false cpusets_pre_enable_key;
35 extern struct static_key_false cpusets_enabled_key;
36 static inline bool cpusets_enabled(void)
38 return static_branch_unlikely(&cpusets_enabled_key);
41 static inline void cpuset_inc(void)
43 static_branch_inc(&cpusets_pre_enable_key);
44 static_branch_inc(&cpusets_enabled_key);
47 static inline void cpuset_dec(void)
49 static_branch_dec(&cpusets_enabled_key);
50 static_branch_dec(&cpusets_pre_enable_key);
53 extern int cpuset_init(void);
54 extern void cpuset_init_smp(void);
55 extern void cpuset_update_active_cpus(void);
56 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
57 extern void cpuset_cpus_allowed_fallback(struct task_struct *p);
58 extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
59 #define cpuset_current_mems_allowed (current->mems_allowed)
60 void cpuset_init_current_mems_allowed(void);
61 int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
63 extern bool __cpuset_node_allowed(int node, gfp_t gfp_mask);
65 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
67 if (cpusets_enabled())
68 return __cpuset_node_allowed(node, gfp_mask);
72 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
74 return __cpuset_node_allowed(zone_to_nid(z), gfp_mask);
77 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
79 if (cpusets_enabled())
80 return __cpuset_zone_allowed(z, gfp_mask);
84 extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
85 const struct task_struct *tsk2);
87 #define cpuset_memory_pressure_bump() \
89 if (cpuset_memory_pressure_enabled) \
90 __cpuset_memory_pressure_bump(); \
92 extern int cpuset_memory_pressure_enabled;
93 extern void __cpuset_memory_pressure_bump(void);
95 extern void cpuset_task_status_allowed(struct seq_file *m,
96 struct task_struct *task);
97 extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
98 struct pid *pid, struct task_struct *tsk);
100 extern int cpuset_mem_spread_node(void);
101 extern int cpuset_slab_spread_node(void);
103 static inline int cpuset_do_page_mem_spread(void)
105 return task_spread_page(current);
108 static inline int cpuset_do_slab_mem_spread(void)
110 return task_spread_slab(current);
113 extern int current_cpuset_is_being_rebound(void);
115 extern void rebuild_sched_domains(void);
117 extern void cpuset_print_current_mems_allowed(void);
120 * read_mems_allowed_begin is required when making decisions involving
121 * mems_allowed such as during page allocation. mems_allowed can be updated in
122 * parallel and depending on the new value an operation can fail potentially
123 * causing process failure. A retry loop with read_mems_allowed_begin and
124 * read_mems_allowed_retry prevents these artificial failures.
126 static inline unsigned int read_mems_allowed_begin(void)
128 if (!static_branch_unlikely(&cpusets_pre_enable_key))
131 return read_seqcount_begin(¤t->mems_allowed_seq);
135 * If this returns true, the operation that took place after
136 * read_mems_allowed_begin may have failed artificially due to a concurrent
137 * update of mems_allowed. It is up to the caller to retry the operation if
140 static inline bool read_mems_allowed_retry(unsigned int seq)
142 if (!static_branch_unlikely(&cpusets_enabled_key))
145 return read_seqcount_retry(¤t->mems_allowed_seq, seq);
148 static inline void set_mems_allowed(nodemask_t nodemask)
153 local_irq_save(flags);
154 write_seqcount_begin(¤t->mems_allowed_seq);
155 current->mems_allowed = nodemask;
156 write_seqcount_end(¤t->mems_allowed_seq);
157 local_irq_restore(flags);
158 task_unlock(current);
161 #else /* !CONFIG_CPUSETS */
163 static inline bool cpusets_enabled(void) { return false; }
165 static inline int cpuset_init(void) { return 0; }
166 static inline void cpuset_init_smp(void) {}
168 static inline void cpuset_update_active_cpus(void)
170 partition_sched_domains(1, NULL, NULL);
173 static inline void cpuset_cpus_allowed(struct task_struct *p,
174 struct cpumask *mask)
176 cpumask_copy(mask, cpu_possible_mask);
179 static inline void cpuset_cpus_allowed_fallback(struct task_struct *p)
183 static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
185 return node_possible_map;
188 #define cpuset_current_mems_allowed (node_states[N_MEMORY])
189 static inline void cpuset_init_current_mems_allowed(void) {}
191 static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
196 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
201 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
206 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
211 static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
212 const struct task_struct *tsk2)
217 static inline void cpuset_memory_pressure_bump(void) {}
219 static inline void cpuset_task_status_allowed(struct seq_file *m,
220 struct task_struct *task)
224 static inline int cpuset_mem_spread_node(void)
229 static inline int cpuset_slab_spread_node(void)
234 static inline int cpuset_do_page_mem_spread(void)
239 static inline int cpuset_do_slab_mem_spread(void)
244 static inline int current_cpuset_is_being_rebound(void)
249 static inline void rebuild_sched_domains(void)
251 partition_sched_domains(1, NULL, NULL);
254 static inline void cpuset_print_current_mems_allowed(void)
258 static inline void set_mems_allowed(nodemask_t nodemask)
262 static inline unsigned int read_mems_allowed_begin(void)
267 static inline bool read_mems_allowed_retry(unsigned int seq)
272 #endif /* !CONFIG_CPUSETS */
274 #endif /* _LINUX_CPUSET_H */