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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_CPUSET_H
3#define _LINUX_CPUSET_H
4/*
5 * cpuset interface
6 *
7 * Copyright (C) 2003 BULL SA
8 * Copyright (C) 2004-2006 Silicon Graphics, Inc.
9 *
10 */
11
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>
17#include <linux/mm.h>
18#include <linux/mmu_context.h>
19#include <linux/jump_label.h>
20
21#ifdef CONFIG_CPUSETS
22
23/*
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).
34 */
35extern struct static_key_false cpusets_pre_enable_key;
36extern struct static_key_false cpusets_enabled_key;
37static inline bool cpusets_enabled(void)
38{
39 return static_branch_unlikely(&cpusets_enabled_key);
40}
41
42static inline void cpuset_inc(void)
43{
44 static_branch_inc_cpuslocked(&cpusets_pre_enable_key);
45 static_branch_inc_cpuslocked(&cpusets_enabled_key);
46}
47
48static inline void cpuset_dec(void)
49{
50 static_branch_dec_cpuslocked(&cpusets_enabled_key);
51 static_branch_dec_cpuslocked(&cpusets_pre_enable_key);
52}
53
54extern int cpuset_init(void);
55extern void cpuset_init_smp(void);
56extern void cpuset_force_rebuild(void);
57extern void cpuset_update_active_cpus(void);
58extern void cpuset_wait_for_hotplug(void);
59extern void cpuset_read_lock(void);
60extern void cpuset_read_unlock(void);
61extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
62extern bool cpuset_cpus_allowed_fallback(struct task_struct *p);
63extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
64#define cpuset_current_mems_allowed (current->mems_allowed)
65void cpuset_init_current_mems_allowed(void);
66int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
67
68extern bool __cpuset_node_allowed(int node, gfp_t gfp_mask);
69
70static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
71{
72 if (cpusets_enabled())
73 return __cpuset_node_allowed(node, gfp_mask);
74 return true;
75}
76
77static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
78{
79 return __cpuset_node_allowed(zone_to_nid(z), gfp_mask);
80}
81
82static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
83{
84 if (cpusets_enabled())
85 return __cpuset_zone_allowed(z, gfp_mask);
86 return true;
87}
88
89extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
90 const struct task_struct *tsk2);
91
92#define cpuset_memory_pressure_bump() \
93 do { \
94 if (cpuset_memory_pressure_enabled) \
95 __cpuset_memory_pressure_bump(); \
96 } while (0)
97extern int cpuset_memory_pressure_enabled;
98extern void __cpuset_memory_pressure_bump(void);
99
100extern void cpuset_task_status_allowed(struct seq_file *m,
101 struct task_struct *task);
102extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
103 struct pid *pid, struct task_struct *tsk);
104
105extern int cpuset_mem_spread_node(void);
106extern int cpuset_slab_spread_node(void);
107
108static inline int cpuset_do_page_mem_spread(void)
109{
110 return task_spread_page(current);
111}
112
113static inline int cpuset_do_slab_mem_spread(void)
114{
115 return task_spread_slab(current);
116}
117
118extern bool current_cpuset_is_being_rebound(void);
119
120extern void rebuild_sched_domains(void);
121
122extern void cpuset_print_current_mems_allowed(void);
123
124/*
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.
130 */
131static inline unsigned int read_mems_allowed_begin(void)
132{
133 if (!static_branch_unlikely(&cpusets_pre_enable_key))
134 return 0;
135
136 return read_seqcount_begin(¤t->mems_allowed_seq);
137}
138
139/*
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
143 * appropriate.
144 */
145static inline bool read_mems_allowed_retry(unsigned int seq)
146{
147 if (!static_branch_unlikely(&cpusets_enabled_key))
148 return false;
149
150 return read_seqcount_retry(¤t->mems_allowed_seq, seq);
151}
152
153static inline void set_mems_allowed(nodemask_t nodemask)
154{
155 unsigned long flags;
156
157 task_lock(current);
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);
164}
165
166#else /* !CONFIG_CPUSETS */
167
168static inline bool cpusets_enabled(void) { return false; }
169
170static inline int cpuset_init(void) { return 0; }
171static inline void cpuset_init_smp(void) {}
172
173static inline void cpuset_force_rebuild(void) { }
174
175static inline void cpuset_update_active_cpus(void)
176{
177 partition_sched_domains(1, NULL, NULL);
178}
179
180static inline void cpuset_wait_for_hotplug(void) { }
181
182static inline void cpuset_read_lock(void) { }
183static inline void cpuset_read_unlock(void) { }
184
185static inline void cpuset_cpus_allowed(struct task_struct *p,
186 struct cpumask *mask)
187{
188 cpumask_copy(mask, task_cpu_possible_mask(p));
189}
190
191static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p)
192{
193 return false;
194}
195
196static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
197{
198 return node_possible_map;
199}
200
201#define cpuset_current_mems_allowed (node_states[N_MEMORY])
202static inline void cpuset_init_current_mems_allowed(void) {}
203
204static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
205{
206 return 1;
207}
208
209static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
210{
211 return true;
212}
213
214static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
215{
216 return true;
217}
218
219static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
220{
221 return true;
222}
223
224static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
225 const struct task_struct *tsk2)
226{
227 return 1;
228}
229
230static inline void cpuset_memory_pressure_bump(void) {}
231
232static inline void cpuset_task_status_allowed(struct seq_file *m,
233 struct task_struct *task)
234{
235}
236
237static inline int cpuset_mem_spread_node(void)
238{
239 return 0;
240}
241
242static inline int cpuset_slab_spread_node(void)
243{
244 return 0;
245}
246
247static inline int cpuset_do_page_mem_spread(void)
248{
249 return 0;
250}
251
252static inline int cpuset_do_slab_mem_spread(void)
253{
254 return 0;
255}
256
257static inline bool current_cpuset_is_being_rebound(void)
258{
259 return false;
260}
261
262static inline void rebuild_sched_domains(void)
263{
264 partition_sched_domains(1, NULL, NULL);
265}
266
267static inline void cpuset_print_current_mems_allowed(void)
268{
269}
270
271static inline void set_mems_allowed(nodemask_t nodemask)
272{
273}
274
275static inline unsigned int read_mems_allowed_begin(void)
276{
277 return 0;
278}
279
280static inline bool read_mems_allowed_retry(unsigned int seq)
281{
282 return false;
283}
284
285#endif /* !CONFIG_CPUSETS */
286
287#endif /* _LINUX_CPUSET_H */