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1da177e4 LT |
1 | #ifndef _LINUX_PERCPU_COUNTER_H |
2 | #define _LINUX_PERCPU_COUNTER_H | |
3 | /* | |
4 | * A simple "approximate counter" for use in ext2 and ext3 superblocks. | |
5 | * | |
6 | * WARNING: these things are HUGE. 4 kbytes per counter on 32-way P4. | |
7 | */ | |
8 | ||
1da177e4 LT |
9 | #include <linux/spinlock.h> |
10 | #include <linux/smp.h> | |
c67ad917 | 11 | #include <linux/list.h> |
1da177e4 LT |
12 | #include <linux/threads.h> |
13 | #include <linux/percpu.h> | |
0216bfcf | 14 | #include <linux/types.h> |
1da177e4 LT |
15 | |
16 | #ifdef CONFIG_SMP | |
17 | ||
18 | struct percpu_counter { | |
19 | spinlock_t lock; | |
0216bfcf | 20 | s64 count; |
c67ad917 AM |
21 | #ifdef CONFIG_HOTPLUG_CPU |
22 | struct list_head list; /* All percpu_counters are on a list */ | |
23 | #endif | |
0216bfcf | 24 | s32 *counters; |
1da177e4 LT |
25 | }; |
26 | ||
179f7ebf | 27 | extern int percpu_counter_batch; |
1da177e4 | 28 | |
ea319518 PZ |
29 | int __percpu_counter_init(struct percpu_counter *fbc, s64 amount, |
30 | struct lock_class_key *key); | |
31 | ||
32 | #define percpu_counter_init(fbc, value) \ | |
33 | ({ \ | |
34 | static struct lock_class_key __key; \ | |
35 | \ | |
36 | __percpu_counter_init(fbc, value, &__key); \ | |
37 | }) | |
38 | ||
c67ad917 | 39 | void percpu_counter_destroy(struct percpu_counter *fbc); |
3a587f47 | 40 | void percpu_counter_set(struct percpu_counter *fbc, s64 amount); |
20e89767 | 41 | void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch); |
02d21168 | 42 | s64 __percpu_counter_sum(struct percpu_counter *fbc); |
1da177e4 | 43 | |
20e89767 | 44 | static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount) |
252e0ba6 | 45 | { |
179f7ebf | 46 | __percpu_counter_add(fbc, amount, percpu_counter_batch); |
252e0ba6 PZ |
47 | } |
48 | ||
bf1d89c8 PZ |
49 | static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc) |
50 | { | |
02d21168 | 51 | s64 ret = __percpu_counter_sum(fbc); |
bf1d89c8 PZ |
52 | return ret < 0 ? 0 : ret; |
53 | } | |
54 | ||
55 | static inline s64 percpu_counter_sum(struct percpu_counter *fbc) | |
56 | { | |
02d21168 | 57 | return __percpu_counter_sum(fbc); |
bf1d89c8 PZ |
58 | } |
59 | ||
0216bfcf | 60 | static inline s64 percpu_counter_read(struct percpu_counter *fbc) |
1da177e4 LT |
61 | { |
62 | return fbc->count; | |
63 | } | |
64 | ||
65 | /* | |
66 | * It is possible for the percpu_counter_read() to return a small negative | |
67 | * number for some counter which should never be negative. | |
0216bfcf | 68 | * |
1da177e4 | 69 | */ |
0216bfcf | 70 | static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) |
1da177e4 | 71 | { |
0216bfcf | 72 | s64 ret = fbc->count; |
1da177e4 LT |
73 | |
74 | barrier(); /* Prevent reloads of fbc->count */ | |
0216bfcf | 75 | if (ret >= 0) |
1da177e4 LT |
76 | return ret; |
77 | return 1; | |
78 | } | |
79 | ||
80 | #else | |
81 | ||
82 | struct percpu_counter { | |
0216bfcf | 83 | s64 count; |
1da177e4 LT |
84 | }; |
85 | ||
833f4077 | 86 | static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount) |
1da177e4 | 87 | { |
0216bfcf | 88 | fbc->count = amount; |
833f4077 | 89 | return 0; |
1da177e4 LT |
90 | } |
91 | ||
92 | static inline void percpu_counter_destroy(struct percpu_counter *fbc) | |
93 | { | |
94 | } | |
95 | ||
3a587f47 PZ |
96 | static inline void percpu_counter_set(struct percpu_counter *fbc, s64 amount) |
97 | { | |
98 | fbc->count = amount; | |
99 | } | |
100 | ||
252e0ba6 PZ |
101 | #define __percpu_counter_add(fbc, amount, batch) \ |
102 | percpu_counter_add(fbc, amount) | |
103 | ||
1da177e4 | 104 | static inline void |
20e89767 | 105 | percpu_counter_add(struct percpu_counter *fbc, s64 amount) |
1da177e4 LT |
106 | { |
107 | preempt_disable(); | |
108 | fbc->count += amount; | |
109 | preempt_enable(); | |
110 | } | |
111 | ||
0216bfcf | 112 | static inline s64 percpu_counter_read(struct percpu_counter *fbc) |
1da177e4 LT |
113 | { |
114 | return fbc->count; | |
115 | } | |
116 | ||
0216bfcf | 117 | static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) |
1da177e4 LT |
118 | { |
119 | return fbc->count; | |
120 | } | |
121 | ||
52d9f3b4 | 122 | static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc) |
e2bab3d9 AM |
123 | { |
124 | return percpu_counter_read_positive(fbc); | |
125 | } | |
126 | ||
bf1d89c8 PZ |
127 | static inline s64 percpu_counter_sum(struct percpu_counter *fbc) |
128 | { | |
129 | return percpu_counter_read(fbc); | |
130 | } | |
131 | ||
1da177e4 LT |
132 | #endif /* CONFIG_SMP */ |
133 | ||
134 | static inline void percpu_counter_inc(struct percpu_counter *fbc) | |
135 | { | |
aa0dff2d | 136 | percpu_counter_add(fbc, 1); |
1da177e4 LT |
137 | } |
138 | ||
139 | static inline void percpu_counter_dec(struct percpu_counter *fbc) | |
140 | { | |
aa0dff2d | 141 | percpu_counter_add(fbc, -1); |
1da177e4 LT |
142 | } |
143 | ||
3cb4f9fa PZ |
144 | static inline void percpu_counter_sub(struct percpu_counter *fbc, s64 amount) |
145 | { | |
146 | percpu_counter_add(fbc, -amount); | |
147 | } | |
148 | ||
1da177e4 | 149 | #endif /* _LINUX_PERCPU_COUNTER_H */ |