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1 | #ifndef __PERCPU_IDA_H__ |
2 | #define __PERCPU_IDA_H__ | |
3 | ||
4 | #include <linux/types.h> | |
5 | #include <linux/bitops.h> | |
6 | #include <linux/init.h> | |
6f6b5d1e | 7 | #include <linux/sched.h> |
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8 | #include <linux/spinlock_types.h> |
9 | #include <linux/wait.h> | |
10 | #include <linux/cpumask.h> | |
11 | ||
12 | struct percpu_ida_cpu; | |
13 | ||
14 | struct percpu_ida { | |
15 | /* | |
16 | * number of tags available to be allocated, as passed to | |
17 | * percpu_ida_init() | |
18 | */ | |
19 | unsigned nr_tags; | |
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20 | unsigned percpu_max_size; |
21 | unsigned percpu_batch_size; | |
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22 | |
23 | struct percpu_ida_cpu __percpu *tag_cpu; | |
24 | ||
25 | /* | |
26 | * Bitmap of cpus that (may) have tags on their percpu freelists: | |
27 | * steal_tags() uses this to decide when to steal tags, and which cpus | |
28 | * to try stealing from. | |
29 | * | |
30 | * It's ok for a freelist to be empty when its bit is set - steal_tags() | |
31 | * will just keep looking - but the bitmap _must_ be set whenever a | |
32 | * percpu freelist does have tags. | |
33 | */ | |
34 | cpumask_t cpus_have_tags; | |
35 | ||
36 | struct { | |
37 | spinlock_t lock; | |
38 | /* | |
39 | * When we go to steal tags from another cpu (see steal_tags()), | |
40 | * we want to pick a cpu at random. Cycling through them every | |
41 | * time we steal is a bit easier and more or less equivalent: | |
42 | */ | |
43 | unsigned cpu_last_stolen; | |
44 | ||
45 | /* For sleeping on allocation failure */ | |
46 | wait_queue_head_t wait; | |
47 | ||
48 | /* | |
49 | * Global freelist - it's a stack where nr_free points to the | |
50 | * top | |
51 | */ | |
52 | unsigned nr_free; | |
53 | unsigned *freelist; | |
54 | } ____cacheline_aligned_in_smp; | |
55 | }; | |
56 | ||
e26b53d0 SL |
57 | /* |
58 | * Number of tags we move between the percpu freelist and the global freelist at | |
59 | * a time | |
60 | */ | |
61 | #define IDA_DEFAULT_PCPU_BATCH_MOVE 32U | |
62 | /* Max size of percpu freelist, */ | |
63 | #define IDA_DEFAULT_PCPU_SIZE ((IDA_DEFAULT_PCPU_BATCH_MOVE * 3) / 2) | |
64 | ||
6f6b5d1e | 65 | int percpu_ida_alloc(struct percpu_ida *pool, int state); |
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66 | void percpu_ida_free(struct percpu_ida *pool, unsigned tag); |
67 | ||
68 | void percpu_ida_destroy(struct percpu_ida *pool); | |
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69 | int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags, |
70 | unsigned long max_size, unsigned long batch_size); | |
71 | static inline int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags) | |
72 | { | |
73 | return __percpu_ida_init(pool, nr_tags, IDA_DEFAULT_PCPU_SIZE, | |
74 | IDA_DEFAULT_PCPU_BATCH_MOVE); | |
75 | } | |
798ab48e | 76 | |
7fc2ba17 SL |
77 | typedef int (*percpu_ida_cb)(unsigned, void *); |
78 | int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn, | |
79 | void *data); | |
80 | ||
1dddc01a | 81 | unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu); |
798ab48e | 82 | #endif /* __PERCPU_IDA_H__ */ |