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 nodemask_t cpuset_mems_allowed(struct task_struct *p);
81#define cpuset_current_mems_allowed (current->mems_allowed)
82void cpuset_init_current_mems_allowed(void);
83int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
84
85extern bool cpuset_node_allowed(int node, gfp_t gfp_mask);
86
87static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
88{
89 return cpuset_node_allowed(node: zone_to_nid(zone: z), gfp_mask);
90}
91
92static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
93{
94 if (cpusets_enabled())
95 return __cpuset_zone_allowed(z, gfp_mask);
96 return true;
97}
98
99extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
100 const struct task_struct *tsk2);
101
102#define cpuset_memory_pressure_bump() \
103 do { \
104 if (cpuset_memory_pressure_enabled) \
105 __cpuset_memory_pressure_bump(); \
106 } while (0)
107extern int cpuset_memory_pressure_enabled;
108extern void __cpuset_memory_pressure_bump(void);
109
110extern void cpuset_task_status_allowed(struct seq_file *m,
111 struct task_struct *task);
112extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
113 struct pid *pid, struct task_struct *tsk);
114
115extern int cpuset_mem_spread_node(void);
116extern int cpuset_slab_spread_node(void);
117
118static inline int cpuset_do_page_mem_spread(void)
119{
120 return task_spread_page(current);
121}
122
123static inline int cpuset_do_slab_mem_spread(void)
124{
125 return task_spread_slab(current);
126}
127
128extern bool current_cpuset_is_being_rebound(void);
129
130extern void rebuild_sched_domains(void);
131
132extern void cpuset_print_current_mems_allowed(void);
133
134/*
135 * read_mems_allowed_begin is required when making decisions involving
136 * mems_allowed such as during page allocation. mems_allowed can be updated in
137 * parallel and depending on the new value an operation can fail potentially
138 * causing process failure. A retry loop with read_mems_allowed_begin and
139 * read_mems_allowed_retry prevents these artificial failures.
140 */
141static inline unsigned int read_mems_allowed_begin(void)
142{
143 if (!static_branch_unlikely(&cpusets_pre_enable_key))
144 return 0;
145
146 return read_seqcount_begin(&current->mems_allowed_seq);
147}
148
149/*
150 * If this returns true, the operation that took place after
151 * read_mems_allowed_begin may have failed artificially due to a concurrent
152 * update of mems_allowed. It is up to the caller to retry the operation if
153 * appropriate.
154 */
155static inline bool read_mems_allowed_retry(unsigned int seq)
156{
157 if (!static_branch_unlikely(&cpusets_enabled_key))
158 return false;
159
160 return read_seqcount_retry(&current->mems_allowed_seq, seq);
161}
162
163static inline void set_mems_allowed(nodemask_t nodemask)
164{
165 unsigned long flags;
166
167 task_lock(current);
168 local_irq_save(flags);
169 write_seqcount_begin(&current->mems_allowed_seq);
170 current->mems_allowed = nodemask;
171 write_seqcount_end(&current->mems_allowed_seq);
172 local_irq_restore(flags);
173 task_unlock(current);
174}
175
176#else /* !CONFIG_CPUSETS */
177
178static inline bool cpusets_enabled(void) { return false; }
179
180static inline bool cpusets_insane_config(void) { return false; }
181
182static inline int cpuset_init(void) { return 0; }
183static inline void cpuset_init_smp(void) {}
184
185static inline void cpuset_force_rebuild(void) { }
186
187static inline void cpuset_update_active_cpus(void)
188{
189 partition_sched_domains(1, NULL, NULL);
190}
191
192static inline void cpuset_wait_for_hotplug(void) { }
193
194static inline void inc_dl_tasks_cs(struct task_struct *task) { }
195static inline void dec_dl_tasks_cs(struct task_struct *task) { }
196static inline void cpuset_lock(void) { }
197static inline void cpuset_unlock(void) { }
198
199static inline void cpuset_cpus_allowed(struct task_struct *p,
200 struct cpumask *mask)
201{
202 cpumask_copy(mask, task_cpu_possible_mask(p));
203}
204
205static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p)
206{
207 return false;
208}
209
210static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
211{
212 return node_possible_map;
213}
214
215#define cpuset_current_mems_allowed (node_states[N_MEMORY])
216static inline void cpuset_init_current_mems_allowed(void) {}
217
218static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
219{
220 return 1;
221}
222
223static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
224{
225 return true;
226}
227
228static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
229{
230 return true;
231}
232
233static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
234 const struct task_struct *tsk2)
235{
236 return 1;
237}
238
239static inline void cpuset_memory_pressure_bump(void) {}
240
241static inline void cpuset_task_status_allowed(struct seq_file *m,
242 struct task_struct *task)
243{
244}
245
246static inline int cpuset_mem_spread_node(void)
247{
248 return 0;
249}
250
251static inline int cpuset_slab_spread_node(void)
252{
253 return 0;
254}
255
256static inline int cpuset_do_page_mem_spread(void)
257{
258 return 0;
259}
260
261static inline int cpuset_do_slab_mem_spread(void)
262{
263 return 0;
264}
265
266static inline bool current_cpuset_is_being_rebound(void)
267{
268 return false;
269}
270
271static inline void rebuild_sched_domains(void)
272{
273 partition_sched_domains(1, NULL, NULL);
274}
275
276static inline void cpuset_print_current_mems_allowed(void)
277{
278}
279
280static inline void set_mems_allowed(nodemask_t nodemask)
281{
282}
283
284static inline unsigned int read_mems_allowed_begin(void)
285{
286 return 0;
287}
288
289static inline bool read_mems_allowed_retry(unsigned int seq)
290{
291 return false;
292}
293
294#endif /* !CONFIG_CPUSETS */
295
296#endif /* _LINUX_CPUSET_H */
297

source code of linux/include/linux/cpuset.h