1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2016 Facebook
4 #include "percpu_freelist.h"
6 int pcpu_freelist_init(struct pcpu_freelist *s)
10 s->freelist = alloc_percpu(struct pcpu_freelist_head);
14 for_each_possible_cpu(cpu) {
15 struct pcpu_freelist_head *head = per_cpu_ptr(s->freelist, cpu);
17 raw_spin_lock_init(&head->lock);
20 raw_spin_lock_init(&s->extralist.lock);
21 s->extralist.first = NULL;
25 void pcpu_freelist_destroy(struct pcpu_freelist *s)
27 free_percpu(s->freelist);
30 static inline void pcpu_freelist_push_node(struct pcpu_freelist_head *head,
31 struct pcpu_freelist_node *node)
33 node->next = head->first;
37 static inline void ___pcpu_freelist_push(struct pcpu_freelist_head *head,
38 struct pcpu_freelist_node *node)
40 raw_spin_lock(&head->lock);
41 pcpu_freelist_push_node(head, node);
42 raw_spin_unlock(&head->lock);
45 static inline bool pcpu_freelist_try_push_extra(struct pcpu_freelist *s,
46 struct pcpu_freelist_node *node)
48 if (!raw_spin_trylock(&s->extralist.lock))
51 pcpu_freelist_push_node(&s->extralist, node);
52 raw_spin_unlock(&s->extralist.lock);
56 static inline void ___pcpu_freelist_push_nmi(struct pcpu_freelist *s,
57 struct pcpu_freelist_node *node)
61 orig_cpu = cpu = raw_smp_processor_id();
63 struct pcpu_freelist_head *head;
65 head = per_cpu_ptr(s->freelist, cpu);
66 if (raw_spin_trylock(&head->lock)) {
67 pcpu_freelist_push_node(head, node);
68 raw_spin_unlock(&head->lock);
71 cpu = cpumask_next(cpu, cpu_possible_mask);
72 if (cpu >= nr_cpu_ids)
75 /* cannot lock any per cpu lock, try extralist */
76 if (cpu == orig_cpu &&
77 pcpu_freelist_try_push_extra(s, node))
82 void __pcpu_freelist_push(struct pcpu_freelist *s,
83 struct pcpu_freelist_node *node)
86 ___pcpu_freelist_push_nmi(s, node);
88 ___pcpu_freelist_push(this_cpu_ptr(s->freelist), node);
91 void pcpu_freelist_push(struct pcpu_freelist *s,
92 struct pcpu_freelist_node *node)
96 local_irq_save(flags);
97 __pcpu_freelist_push(s, node);
98 local_irq_restore(flags);
101 void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
104 struct pcpu_freelist_head *head;
105 int i, cpu, pcpu_entries;
107 pcpu_entries = nr_elems / num_possible_cpus() + 1;
110 for_each_possible_cpu(cpu) {
112 head = per_cpu_ptr(s->freelist, cpu);
113 /* No locking required as this is not visible yet. */
114 pcpu_freelist_push_node(head, buf);
119 if (i % pcpu_entries)
124 static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s)
126 struct pcpu_freelist_head *head;
127 struct pcpu_freelist_node *node;
130 orig_cpu = cpu = raw_smp_processor_id();
132 head = per_cpu_ptr(s->freelist, cpu);
133 raw_spin_lock(&head->lock);
136 head->first = node->next;
137 raw_spin_unlock(&head->lock);
140 raw_spin_unlock(&head->lock);
141 cpu = cpumask_next(cpu, cpu_possible_mask);
142 if (cpu >= nr_cpu_ids)
148 /* per cpu lists are all empty, try extralist */
149 raw_spin_lock(&s->extralist.lock);
150 node = s->extralist.first;
152 s->extralist.first = node->next;
153 raw_spin_unlock(&s->extralist.lock);
157 static struct pcpu_freelist_node *
158 ___pcpu_freelist_pop_nmi(struct pcpu_freelist *s)
160 struct pcpu_freelist_head *head;
161 struct pcpu_freelist_node *node;
164 orig_cpu = cpu = raw_smp_processor_id();
166 head = per_cpu_ptr(s->freelist, cpu);
167 if (raw_spin_trylock(&head->lock)) {
170 head->first = node->next;
171 raw_spin_unlock(&head->lock);
174 raw_spin_unlock(&head->lock);
176 cpu = cpumask_next(cpu, cpu_possible_mask);
177 if (cpu >= nr_cpu_ids)
183 /* cannot pop from per cpu lists, try extralist */
184 if (!raw_spin_trylock(&s->extralist.lock))
186 node = s->extralist.first;
188 s->extralist.first = node->next;
189 raw_spin_unlock(&s->extralist.lock);
193 struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *s)
196 return ___pcpu_freelist_pop_nmi(s);
197 return ___pcpu_freelist_pop(s);
200 struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
202 struct pcpu_freelist_node *ret;
205 local_irq_save(flags);
206 ret = __pcpu_freelist_pop(s);
207 local_irq_restore(flags);