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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;
37extern struct static_key_false cpusets_insane_config_key;
38
39static inline bool cpusets_enabled(void)
40{
41 return static_branch_unlikely(&cpusets_enabled_key);
42}
43
44static inline void cpuset_inc(void)
45{
46 static_branch_inc_cpuslocked(&cpusets_pre_enable_key);
47 static_branch_inc_cpuslocked(&cpusets_enabled_key);
48}
49
50static inline void cpuset_dec(void)
51{
52 static_branch_dec_cpuslocked(&cpusets_enabled_key);
53 static_branch_dec_cpuslocked(&cpusets_pre_enable_key);
54}
55
56/*
57 * This will get enabled whenever a cpuset configuration is considered
58 * unsupportable in general. E.g. movable only node which cannot satisfy
59 * any non movable allocations (see update_nodemask). Page allocator
60 * needs to make additional checks for those configurations and this
61 * check is meant to guard those checks without any overhead for sane
62 * configurations.
63 */
64static inline bool cpusets_insane_config(void)
65{
66 return static_branch_unlikely(&cpusets_insane_config_key);
67}
68
69extern int cpuset_init(void);
70extern void cpuset_init_smp(void);
71extern void cpuset_force_rebuild(void);
72extern void cpuset_update_active_cpus(void);
73extern void cpuset_wait_for_hotplug(void);
74extern void inc_dl_tasks_cs(struct task_struct *task);
75extern void dec_dl_tasks_cs(struct task_struct *task);
76extern void cpuset_lock(void);
77extern void cpuset_unlock(void);
78extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
79extern bool cpuset_cpus_allowed_fallback(struct task_struct *p);
80extern bool cpuset_cpu_is_isolated(int cpu);
81extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
82#define cpuset_current_mems_allowed (current->mems_allowed)
83void cpuset_init_current_mems_allowed(void);
84int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
85
86extern bool cpuset_node_allowed(int node, gfp_t gfp_mask);
87
88static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
89{
90 return cpuset_node_allowed(zone_to_nid(z), gfp_mask);
91}
92
93static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
94{
95 if (cpusets_enabled())
96 return __cpuset_zone_allowed(z, gfp_mask);
97 return true;
98}
99
100extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
101 const struct task_struct *tsk2);
102
103#define cpuset_memory_pressure_bump() \
104 do { \
105 if (cpuset_memory_pressure_enabled) \
106 __cpuset_memory_pressure_bump(); \
107 } while (0)
108extern int cpuset_memory_pressure_enabled;
109extern void __cpuset_memory_pressure_bump(void);
110
111extern void cpuset_task_status_allowed(struct seq_file *m,
112 struct task_struct *task);
113extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
114 struct pid *pid, struct task_struct *tsk);
115
116extern int cpuset_mem_spread_node(void);
117extern int cpuset_slab_spread_node(void);
118
119static inline int cpuset_do_page_mem_spread(void)
120{
121 return task_spread_page(current);
122}
123
124static inline int cpuset_do_slab_mem_spread(void)
125{
126 return task_spread_slab(current);
127}
128
129extern bool current_cpuset_is_being_rebound(void);
130
131extern void rebuild_sched_domains(void);
132
133extern void cpuset_print_current_mems_allowed(void);
134
135/*
136 * read_mems_allowed_begin is required when making decisions involving
137 * mems_allowed such as during page allocation. mems_allowed can be updated in
138 * parallel and depending on the new value an operation can fail potentially
139 * causing process failure. A retry loop with read_mems_allowed_begin and
140 * read_mems_allowed_retry prevents these artificial failures.
141 */
142static inline unsigned int read_mems_allowed_begin(void)
143{
144 if (!static_branch_unlikely(&cpusets_pre_enable_key))
145 return 0;
146
147 return read_seqcount_begin(¤t->mems_allowed_seq);
148}
149
150/*
151 * If this returns true, the operation that took place after
152 * read_mems_allowed_begin may have failed artificially due to a concurrent
153 * update of mems_allowed. It is up to the caller to retry the operation if
154 * appropriate.
155 */
156static inline bool read_mems_allowed_retry(unsigned int seq)
157{
158 if (!static_branch_unlikely(&cpusets_enabled_key))
159 return false;
160
161 return read_seqcount_retry(¤t->mems_allowed_seq, seq);
162}
163
164static inline void set_mems_allowed(nodemask_t nodemask)
165{
166 unsigned long flags;
167
168 task_lock(current);
169 local_irq_save(flags);
170 write_seqcount_begin(¤t->mems_allowed_seq);
171 current->mems_allowed = nodemask;
172 write_seqcount_end(¤t->mems_allowed_seq);
173 local_irq_restore(flags);
174 task_unlock(current);
175}
176
177#else /* !CONFIG_CPUSETS */
178
179static inline bool cpusets_enabled(void) { return false; }
180
181static inline bool cpusets_insane_config(void) { return false; }
182
183static inline int cpuset_init(void) { return 0; }
184static inline void cpuset_init_smp(void) {}
185
186static inline void cpuset_force_rebuild(void) { }
187
188static inline void cpuset_update_active_cpus(void)
189{
190 partition_sched_domains(1, NULL, NULL);
191}
192
193static inline void cpuset_wait_for_hotplug(void) { }
194
195static inline void inc_dl_tasks_cs(struct task_struct *task) { }
196static inline void dec_dl_tasks_cs(struct task_struct *task) { }
197static inline void cpuset_lock(void) { }
198static inline void cpuset_unlock(void) { }
199
200static inline void cpuset_cpus_allowed(struct task_struct *p,
201 struct cpumask *mask)
202{
203 cpumask_copy(mask, task_cpu_possible_mask(p));
204}
205
206static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p)
207{
208 return false;
209}
210
211static inline bool cpuset_cpu_is_isolated(int cpu)
212{
213 return false;
214}
215
216static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
217{
218 return node_possible_map;
219}
220
221#define cpuset_current_mems_allowed (node_states[N_MEMORY])
222static inline void cpuset_init_current_mems_allowed(void) {}
223
224static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
225{
226 return 1;
227}
228
229static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
230{
231 return true;
232}
233
234static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
235{
236 return true;
237}
238
239static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
240 const struct task_struct *tsk2)
241{
242 return 1;
243}
244
245static inline void cpuset_memory_pressure_bump(void) {}
246
247static inline void cpuset_task_status_allowed(struct seq_file *m,
248 struct task_struct *task)
249{
250}
251
252static inline int cpuset_mem_spread_node(void)
253{
254 return 0;
255}
256
257static inline int cpuset_slab_spread_node(void)
258{
259 return 0;
260}
261
262static inline int cpuset_do_page_mem_spread(void)
263{
264 return 0;
265}
266
267static inline int cpuset_do_slab_mem_spread(void)
268{
269 return 0;
270}
271
272static inline bool current_cpuset_is_being_rebound(void)
273{
274 return false;
275}
276
277static inline void rebuild_sched_domains(void)
278{
279 partition_sched_domains(1, NULL, NULL);
280}
281
282static inline void cpuset_print_current_mems_allowed(void)
283{
284}
285
286static inline void set_mems_allowed(nodemask_t nodemask)
287{
288}
289
290static inline unsigned int read_mems_allowed_begin(void)
291{
292 return 0;
293}
294
295static inline bool read_mems_allowed_retry(unsigned int seq)
296{
297 return false;
298}
299
300#endif /* !CONFIG_CPUSETS */
301
302#endif /* _LINUX_CPUSET_H */