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  */
35 extern struct static_key_false cpusets_pre_enable_key;
36 extern struct static_key_false cpusets_enabled_key;
37 extern struct static_key_false cpusets_insane_config_key;
38 
cpusets_enabled(void)39 static inline bool cpusets_enabled(void)
40 {
41 	return static_branch_unlikely(&cpusets_enabled_key);
42 }
43 
cpuset_inc(void)44 static 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 
cpuset_dec(void)50 static 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  */
cpusets_insane_config(void)64 static inline bool cpusets_insane_config(void)
65 {
66 	return static_branch_unlikely(&cpusets_insane_config_key);
67 }
68 
69 extern int cpuset_init(void);
70 extern void cpuset_init_smp(void);
71 extern void cpuset_force_rebuild(void);
72 extern void cpuset_update_active_cpus(void);
73 extern void cpuset_wait_for_hotplug(void);
74 extern void cpuset_read_lock(void);
75 extern void cpuset_read_unlock(void);
76 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
77 extern bool cpuset_cpus_allowed_fallback(struct task_struct *p);
78 extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
79 #define cpuset_current_mems_allowed (current->mems_allowed)
80 void cpuset_init_current_mems_allowed(void);
81 int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
82 
83 extern bool __cpuset_node_allowed(int node, gfp_t gfp_mask);
84 
cpuset_node_allowed(int node,gfp_t gfp_mask)85 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
86 {
87 	if (cpusets_enabled())
88 		return __cpuset_node_allowed(node, gfp_mask);
89 	return true;
90 }
91 
__cpuset_zone_allowed(struct zone * z,gfp_t gfp_mask)92 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
93 {
94 	return __cpuset_node_allowed(zone_to_nid(z), gfp_mask);
95 }
96 
cpuset_zone_allowed(struct zone * z,gfp_t gfp_mask)97 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
98 {
99 	if (cpusets_enabled())
100 		return __cpuset_zone_allowed(z, gfp_mask);
101 	return true;
102 }
103 
104 extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
105 					  const struct task_struct *tsk2);
106 
107 #define cpuset_memory_pressure_bump() 				\
108 	do {							\
109 		if (cpuset_memory_pressure_enabled)		\
110 			__cpuset_memory_pressure_bump();	\
111 	} while (0)
112 extern int cpuset_memory_pressure_enabled;
113 extern void __cpuset_memory_pressure_bump(void);
114 
115 extern void cpuset_task_status_allowed(struct seq_file *m,
116 					struct task_struct *task);
117 extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
118 			    struct pid *pid, struct task_struct *tsk);
119 
120 extern int cpuset_mem_spread_node(void);
121 extern int cpuset_slab_spread_node(void);
122 
cpuset_do_page_mem_spread(void)123 static inline int cpuset_do_page_mem_spread(void)
124 {
125 	return task_spread_page(current);
126 }
127 
cpuset_do_slab_mem_spread(void)128 static inline int cpuset_do_slab_mem_spread(void)
129 {
130 	return task_spread_slab(current);
131 }
132 
133 extern bool current_cpuset_is_being_rebound(void);
134 
135 extern void rebuild_sched_domains(void);
136 
137 extern void cpuset_print_current_mems_allowed(void);
138 
139 /*
140  * read_mems_allowed_begin is required when making decisions involving
141  * mems_allowed such as during page allocation. mems_allowed can be updated in
142  * parallel and depending on the new value an operation can fail potentially
143  * causing process failure. A retry loop with read_mems_allowed_begin and
144  * read_mems_allowed_retry prevents these artificial failures.
145  */
read_mems_allowed_begin(void)146 static inline unsigned int read_mems_allowed_begin(void)
147 {
148 	if (!static_branch_unlikely(&cpusets_pre_enable_key))
149 		return 0;
150 
151 	return read_seqcount_begin(&current->mems_allowed_seq);
152 }
153 
154 /*
155  * If this returns true, the operation that took place after
156  * read_mems_allowed_begin may have failed artificially due to a concurrent
157  * update of mems_allowed. It is up to the caller to retry the operation if
158  * appropriate.
159  */
read_mems_allowed_retry(unsigned int seq)160 static inline bool read_mems_allowed_retry(unsigned int seq)
161 {
162 	if (!static_branch_unlikely(&cpusets_enabled_key))
163 		return false;
164 
165 	return read_seqcount_retry(&current->mems_allowed_seq, seq);
166 }
167 
set_mems_allowed(nodemask_t nodemask)168 static inline void set_mems_allowed(nodemask_t nodemask)
169 {
170 	unsigned long flags;
171 
172 	task_lock(current);
173 	local_irq_save(flags);
174 	write_seqcount_begin(&current->mems_allowed_seq);
175 	current->mems_allowed = nodemask;
176 	write_seqcount_end(&current->mems_allowed_seq);
177 	local_irq_restore(flags);
178 	task_unlock(current);
179 }
180 
181 #else /* !CONFIG_CPUSETS */
182 
cpusets_enabled(void)183 static inline bool cpusets_enabled(void) { return false; }
184 
cpusets_insane_config(void)185 static inline bool cpusets_insane_config(void) { return false; }
186 
cpuset_init(void)187 static inline int cpuset_init(void) { return 0; }
cpuset_init_smp(void)188 static inline void cpuset_init_smp(void) {}
189 
cpuset_force_rebuild(void)190 static inline void cpuset_force_rebuild(void) { }
191 
cpuset_update_active_cpus(void)192 static inline void cpuset_update_active_cpus(void)
193 {
194 	partition_sched_domains(1, NULL, NULL);
195 }
196 
cpuset_wait_for_hotplug(void)197 static inline void cpuset_wait_for_hotplug(void) { }
198 
cpuset_read_lock(void)199 static inline void cpuset_read_lock(void) { }
cpuset_read_unlock(void)200 static inline void cpuset_read_unlock(void) { }
201 
cpuset_cpus_allowed(struct task_struct * p,struct cpumask * mask)202 static inline void cpuset_cpus_allowed(struct task_struct *p,
203 				       struct cpumask *mask)
204 {
205 	cpumask_copy(mask, task_cpu_possible_mask(p));
206 }
207 
cpuset_cpus_allowed_fallback(struct task_struct * p)208 static inline bool cpuset_cpus_allowed_fallback(struct task_struct *p)
209 {
210 	return false;
211 }
212 
cpuset_mems_allowed(struct task_struct * p)213 static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
214 {
215 	return node_possible_map;
216 }
217 
218 #define cpuset_current_mems_allowed (node_states[N_MEMORY])
cpuset_init_current_mems_allowed(void)219 static inline void cpuset_init_current_mems_allowed(void) {}
220 
cpuset_nodemask_valid_mems_allowed(nodemask_t * nodemask)221 static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
222 {
223 	return 1;
224 }
225 
cpuset_node_allowed(int node,gfp_t gfp_mask)226 static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask)
227 {
228 	return true;
229 }
230 
__cpuset_zone_allowed(struct zone * z,gfp_t gfp_mask)231 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
232 {
233 	return true;
234 }
235 
cpuset_zone_allowed(struct zone * z,gfp_t gfp_mask)236 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
237 {
238 	return true;
239 }
240 
cpuset_mems_allowed_intersects(const struct task_struct * tsk1,const struct task_struct * tsk2)241 static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
242 						 const struct task_struct *tsk2)
243 {
244 	return 1;
245 }
246 
cpuset_memory_pressure_bump(void)247 static inline void cpuset_memory_pressure_bump(void) {}
248 
cpuset_task_status_allowed(struct seq_file * m,struct task_struct * task)249 static inline void cpuset_task_status_allowed(struct seq_file *m,
250 						struct task_struct *task)
251 {
252 }
253 
cpuset_mem_spread_node(void)254 static inline int cpuset_mem_spread_node(void)
255 {
256 	return 0;
257 }
258 
cpuset_slab_spread_node(void)259 static inline int cpuset_slab_spread_node(void)
260 {
261 	return 0;
262 }
263 
cpuset_do_page_mem_spread(void)264 static inline int cpuset_do_page_mem_spread(void)
265 {
266 	return 0;
267 }
268 
cpuset_do_slab_mem_spread(void)269 static inline int cpuset_do_slab_mem_spread(void)
270 {
271 	return 0;
272 }
273 
current_cpuset_is_being_rebound(void)274 static inline bool current_cpuset_is_being_rebound(void)
275 {
276 	return false;
277 }
278 
rebuild_sched_domains(void)279 static inline void rebuild_sched_domains(void)
280 {
281 	partition_sched_domains(1, NULL, NULL);
282 }
283 
cpuset_print_current_mems_allowed(void)284 static inline void cpuset_print_current_mems_allowed(void)
285 {
286 }
287 
set_mems_allowed(nodemask_t nodemask)288 static inline void set_mems_allowed(nodemask_t nodemask)
289 {
290 }
291 
read_mems_allowed_begin(void)292 static inline unsigned int read_mems_allowed_begin(void)
293 {
294 	return 0;
295 }
296 
read_mems_allowed_retry(unsigned int seq)297 static inline bool read_mems_allowed_retry(unsigned int seq)
298 {
299 	return false;
300 }
301 
302 #endif /* !CONFIG_CPUSETS */
303 
304 #endif /* _LINUX_CPUSET_H */
305