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_force_rebuild(void);
56 extern void cpuset_update_active_cpus(void);
57 extern void cpuset_wait_for_hotplug(void);
58 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
59 extern void cpuset_cpus_allowed_fallback(struct task_struct *p);
60 extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
61 #define cpuset_current_mems_allowed (current->mems_allowed)
62 void cpuset_init_current_mems_allowed(void);
63 int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
65 extern bool __cpuset_node_allowed(int node, gfp_t gfp_mask);
67 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
69 if (cpusets_enabled())
70 return __cpuset_node_allowed(node, gfp_mask);
74 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
76 return __cpuset_node_allowed(zone_to_nid(z), gfp_mask);
79 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
81 if (cpusets_enabled())
82 return __cpuset_zone_allowed(z, gfp_mask);
86 extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
87 const struct task_struct *tsk2);
89 #define cpuset_memory_pressure_bump() \
91 if (cpuset_memory_pressure_enabled) \
92 __cpuset_memory_pressure_bump(); \
94 extern int cpuset_memory_pressure_enabled;
95 extern void __cpuset_memory_pressure_bump(void);
97 extern void cpuset_task_status_allowed(struct seq_file *m,
98 struct task_struct *task);
99 extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
100 struct pid *pid, struct task_struct *tsk);
102 extern int cpuset_mem_spread_node(void);
103 extern int cpuset_slab_spread_node(void);
105 static inline int cpuset_do_page_mem_spread(void)
107 return task_spread_page(current);
110 static inline int cpuset_do_slab_mem_spread(void)
112 return task_spread_slab(current);
115 extern bool current_cpuset_is_being_rebound(void);
117 extern void rebuild_sched_domains(void);
119 extern void cpuset_print_current_mems_allowed(void);
122 * read_mems_allowed_begin is required when making decisions involving
123 * mems_allowed such as during page allocation. mems_allowed can be updated in
124 * parallel and depending on the new value an operation can fail potentially
125 * causing process failure. A retry loop with read_mems_allowed_begin and
126 * read_mems_allowed_retry prevents these artificial failures.
128 static inline unsigned int read_mems_allowed_begin(void)
130 if (!static_branch_unlikely(&cpusets_pre_enable_key))
133 return read_seqcount_begin(¤t->mems_allowed_seq);
137 * If this returns true, the operation that took place after
138 * read_mems_allowed_begin may have failed artificially due to a concurrent
139 * update of mems_allowed. It is up to the caller to retry the operation if
142 static inline bool read_mems_allowed_retry(unsigned int seq)
144 if (!static_branch_unlikely(&cpusets_enabled_key))
147 return read_seqcount_retry(¤t->mems_allowed_seq, seq);
150 static inline void set_mems_allowed(nodemask_t nodemask)
155 local_irq_save(flags);
156 write_seqcount_begin(¤t->mems_allowed_seq);
157 current->mems_allowed = nodemask;
158 write_seqcount_end(¤t->mems_allowed_seq);
159 local_irq_restore(flags);
160 task_unlock(current);
163 #else /* !CONFIG_CPUSETS */
165 static inline bool cpusets_enabled(void) { return false; }
167 static inline int cpuset_init(void) { return 0; }
168 static inline void cpuset_init_smp(void) {}
170 static inline void cpuset_force_rebuild(void) { }
172 static inline void cpuset_update_active_cpus(void)
174 partition_sched_domains(1, NULL, NULL);
177 static inline void cpuset_wait_for_hotplug(void) { }
179 static inline void cpuset_cpus_allowed(struct task_struct *p,
180 struct cpumask *mask)
182 cpumask_copy(mask, cpu_possible_mask);
185 static inline void cpuset_cpus_allowed_fallback(struct task_struct *p)
189 static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
191 return node_possible_map;
194 #define cpuset_current_mems_allowed (node_states[N_MEMORY])
195 static inline void cpuset_init_current_mems_allowed(void) {}
197 static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
202 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
207 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
212 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
217 static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
218 const struct task_struct *tsk2)
223 static inline void cpuset_memory_pressure_bump(void) {}
225 static inline void cpuset_task_status_allowed(struct seq_file *m,
226 struct task_struct *task)
230 static inline int cpuset_mem_spread_node(void)
235 static inline int cpuset_slab_spread_node(void)
240 static inline int cpuset_do_page_mem_spread(void)
245 static inline int cpuset_do_slab_mem_spread(void)
250 static inline bool current_cpuset_is_being_rebound(void)
255 static inline void rebuild_sched_domains(void)
257 partition_sched_domains(1, NULL, NULL);
260 static inline void cpuset_print_current_mems_allowed(void)
264 static inline void set_mems_allowed(nodemask_t nodemask)
268 static inline unsigned int read_mems_allowed_begin(void)
273 static inline bool read_mems_allowed_retry(unsigned int seq)
278 #endif /* !CONFIG_CPUSETS */
280 #endif /* _LINUX_CPUSET_H */