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1#ifndef _LINUX_CPUSET_H
2#define _LINUX_CPUSET_H
3/*
4 * cpuset interface
5 *
6 * Copyright (C) 2003 BULL SA
7 * Copyright (C) 2004-2006 Silicon Graphics, Inc.
8 *
9 */
10
11#include <linux/sched.h>
12#include <linux/sched/topology.h>
13#include <linux/sched/task.h>
14#include <linux/cpumask.h>
15#include <linux/nodemask.h>
16#include <linux/mm.h>
17#include <linux/jump_label.h>
18
19#ifdef CONFIG_CPUSETS
20
21/*
22 * Static branch rewrites can happen in an arbitrary order for a given
23 * key. In code paths where we need to loop with read_mems_allowed_begin() and
24 * read_mems_allowed_retry() to get a consistent view of mems_allowed, we need
25 * to ensure that begin() always gets rewritten before retry() in the
26 * disabled -> enabled transition. If not, then if local irqs are disabled
27 * around the loop, we can deadlock since retry() would always be
28 * comparing the latest value of the mems_allowed seqcount against 0 as
29 * begin() still would see cpusets_enabled() as false. The enabled -> disabled
30 * transition should happen in reverse order for the same reasons (want to stop
31 * looking at real value of mems_allowed.sequence in retry() first).
32 */
33extern struct static_key_false cpusets_pre_enable_key;
34extern struct static_key_false cpusets_enabled_key;
35static inline bool cpusets_enabled(void)
36{
37 return static_branch_unlikely(&cpusets_enabled_key);
38}
39
40static inline int nr_cpusets(void)
41{
42 /* jump label reference count + the top-level cpuset */
43 return static_key_count(&cpusets_enabled_key.key) + 1;
44}
45
46static inline void cpuset_inc(void)
47{
48 static_branch_inc(&cpusets_pre_enable_key);
49 static_branch_inc(&cpusets_enabled_key);
50}
51
52static inline void cpuset_dec(void)
53{
54 static_branch_dec(&cpusets_enabled_key);
55 static_branch_dec(&cpusets_pre_enable_key);
56}
57
58extern int cpuset_init(void);
59extern void cpuset_init_smp(void);
60extern void cpuset_update_active_cpus(void);
61extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
62extern void 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 int 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_update_active_cpus(void)
174{
175 partition_sched_domains(1, NULL, NULL);
176}
177
178static inline void cpuset_cpus_allowed(struct task_struct *p,
179 struct cpumask *mask)
180{
181 cpumask_copy(mask, cpu_possible_mask);
182}
183
184static inline void cpuset_cpus_allowed_fallback(struct task_struct *p)
185{
186}
187
188static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
189{
190 return node_possible_map;
191}
192
193#define cpuset_current_mems_allowed (node_states[N_MEMORY])
194static inline void cpuset_init_current_mems_allowed(void) {}
195
196static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
197{
198 return 1;
199}
200
201static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
202{
203 return true;
204}
205
206static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
207{
208 return true;
209}
210
211static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
212{
213 return true;
214}
215
216static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
217 const struct task_struct *tsk2)
218{
219 return 1;
220}
221
222static inline void cpuset_memory_pressure_bump(void) {}
223
224static inline void cpuset_task_status_allowed(struct seq_file *m,
225 struct task_struct *task)
226{
227}
228
229static inline int cpuset_mem_spread_node(void)
230{
231 return 0;
232}
233
234static inline int cpuset_slab_spread_node(void)
235{
236 return 0;
237}
238
239static inline int cpuset_do_page_mem_spread(void)
240{
241 return 0;
242}
243
244static inline int cpuset_do_slab_mem_spread(void)
245{
246 return 0;
247}
248
249static inline int current_cpuset_is_being_rebound(void)
250{
251 return 0;
252}
253
254static inline void rebuild_sched_domains(void)
255{
256 partition_sched_domains(1, NULL, NULL);
257}
258
259static inline void cpuset_print_current_mems_allowed(void)
260{
261}
262
263static inline void set_mems_allowed(nodemask_t nodemask)
264{
265}
266
267static inline unsigned int read_mems_allowed_begin(void)
268{
269 return 0;
270}
271
272static inline bool read_mems_allowed_retry(unsigned int seq)
273{
274 return false;
275}
276
277#endif /* !CONFIG_CPUSETS */
278
279#endif /* _LINUX_CPUSET_H */