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 cpuset_read_lock(void);
60 extern void cpuset_read_unlock(void);
61 extern void cpuset_cpus_allowed(struct task_struct
*p
, struct cpumask
*mask
);
62 extern bool cpuset_cpus_allowed_fallback(struct task_struct
*p
);
63 extern nodemask_t
cpuset_mems_allowed(struct task_struct
*p
);
64 #define cpuset_current_mems_allowed (current->mems_allowed)
65 void cpuset_init_current_mems_allowed(void);
66 int cpuset_nodemask_valid_mems_allowed(nodemask_t
*nodemask
);
68 extern bool __cpuset_node_allowed(int node
, gfp_t gfp_mask
);
70 static inline bool cpuset_node_allowed(int node
, gfp_t gfp_mask
)
72 if (cpusets_enabled())
73 return __cpuset_node_allowed(node
, gfp_mask
);
77 static inline bool __cpuset_zone_allowed(struct zone
*z
, gfp_t gfp_mask
)
79 return __cpuset_node_allowed(zone_to_nid(z
), gfp_mask
);
82 static inline bool cpuset_zone_allowed(struct zone
*z
, gfp_t gfp_mask
)
84 if (cpusets_enabled())
85 return __cpuset_zone_allowed(z
, gfp_mask
);
89 extern int cpuset_mems_allowed_intersects(const struct task_struct
*tsk1
,
90 const struct task_struct
*tsk2
);
92 #define cpuset_memory_pressure_bump() \
94 if (cpuset_memory_pressure_enabled) \
95 __cpuset_memory_pressure_bump(); \
97 extern int cpuset_memory_pressure_enabled
;
98 extern void __cpuset_memory_pressure_bump(void);
100 extern void cpuset_task_status_allowed(struct seq_file
*m
,
101 struct task_struct
*task
);
102 extern int proc_cpuset_show(struct seq_file
*m
, struct pid_namespace
*ns
,
103 struct pid
*pid
, struct task_struct
*tsk
);
105 extern int cpuset_mem_spread_node(void);
106 extern int cpuset_slab_spread_node(void);
108 static inline int cpuset_do_page_mem_spread(void)
110 return task_spread_page(current
);
113 static inline int cpuset_do_slab_mem_spread(void)
115 return task_spread_slab(current
);
118 extern bool current_cpuset_is_being_rebound(void);
120 extern void rebuild_sched_domains(void);
122 extern void cpuset_print_current_mems_allowed(void);
125 * read_mems_allowed_begin is required when making decisions involving
126 * mems_allowed such as during page allocation. mems_allowed can be updated in
127 * parallel and depending on the new value an operation can fail potentially
128 * causing process failure. A retry loop with read_mems_allowed_begin and
129 * read_mems_allowed_retry prevents these artificial failures.
131 static inline unsigned int read_mems_allowed_begin(void)
133 if (!static_branch_unlikely(&cpusets_pre_enable_key
))
136 return read_seqcount_begin(¤t
->mems_allowed_seq
);
140 * If this returns true, the operation that took place after
141 * read_mems_allowed_begin may have failed artificially due to a concurrent
142 * update of mems_allowed. It is up to the caller to retry the operation if
145 static inline bool read_mems_allowed_retry(unsigned int seq
)
147 if (!static_branch_unlikely(&cpusets_enabled_key
))
150 return read_seqcount_retry(¤t
->mems_allowed_seq
, seq
);
153 static inline void set_mems_allowed(nodemask_t nodemask
)
158 local_irq_save(flags
);
159 write_seqcount_begin(¤t
->mems_allowed_seq
);
160 current
->mems_allowed
= nodemask
;
161 write_seqcount_end(¤t
->mems_allowed_seq
);
162 local_irq_restore(flags
);
163 task_unlock(current
);
166 #else /* !CONFIG_CPUSETS */
168 static inline bool cpusets_enabled(void) { return false; }
170 static inline int cpuset_init(void) { return 0; }
171 static inline void cpuset_init_smp(void) {}
173 static inline void cpuset_force_rebuild(void) { }
175 static inline void cpuset_update_active_cpus(void)
177 partition_sched_domains(1, NULL
, NULL
);
180 static inline void cpuset_wait_for_hotplug(void) { }
182 static inline void cpuset_read_lock(void) { }
183 static inline void cpuset_read_unlock(void) { }
185 static inline void cpuset_cpus_allowed(struct task_struct
*p
,
186 struct cpumask
*mask
)
188 cpumask_copy(mask
, task_cpu_possible_mask(p
));
191 static inline bool cpuset_cpus_allowed_fallback(struct task_struct
*p
)
196 static inline nodemask_t
cpuset_mems_allowed(struct task_struct
*p
)
198 return node_possible_map
;
201 #define cpuset_current_mems_allowed (node_states[N_MEMORY])
202 static inline void cpuset_init_current_mems_allowed(void) {}
204 static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t
*nodemask
)
209 static inline bool cpuset_node_allowed(int node
, gfp_t gfp_mask
)
214 static inline bool __cpuset_zone_allowed(struct zone
*z
, gfp_t gfp_mask
)
219 static inline bool cpuset_zone_allowed(struct zone
*z
, gfp_t gfp_mask
)
224 static inline int cpuset_mems_allowed_intersects(const struct task_struct
*tsk1
,
225 const struct task_struct
*tsk2
)
230 static inline void cpuset_memory_pressure_bump(void) {}
232 static inline void cpuset_task_status_allowed(struct seq_file
*m
,
233 struct task_struct
*task
)
237 static inline int cpuset_mem_spread_node(void)
242 static inline int cpuset_slab_spread_node(void)
247 static inline int cpuset_do_page_mem_spread(void)
252 static inline int cpuset_do_slab_mem_spread(void)
257 static inline bool current_cpuset_is_being_rebound(void)
262 static inline void rebuild_sched_domains(void)
264 partition_sched_domains(1, NULL
, NULL
);
267 static inline void cpuset_print_current_mems_allowed(void)
271 static inline void set_mems_allowed(nodemask_t nodemask
)
275 static inline unsigned int read_mems_allowed_begin(void)
280 static inline bool read_mems_allowed_retry(unsigned int seq
)
285 #endif /* !CONFIG_CPUSETS */
287 #endif /* _LINUX_CPUSET_H */