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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 { | |
f032a450 | 19 | raw_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 | |
43cf38eb | 24 | s32 __percpu *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); |
27f5e0f6 | 43 | int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs); |
1da177e4 | 44 | |
20e89767 | 45 | static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount) |
252e0ba6 | 46 | { |
179f7ebf | 47 | __percpu_counter_add(fbc, amount, percpu_counter_batch); |
252e0ba6 PZ |
48 | } |
49 | ||
bf1d89c8 PZ |
50 | static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc) |
51 | { | |
02d21168 | 52 | s64 ret = __percpu_counter_sum(fbc); |
bf1d89c8 PZ |
53 | return ret < 0 ? 0 : ret; |
54 | } | |
55 | ||
56 | static inline s64 percpu_counter_sum(struct percpu_counter *fbc) | |
57 | { | |
02d21168 | 58 | return __percpu_counter_sum(fbc); |
bf1d89c8 PZ |
59 | } |
60 | ||
0216bfcf | 61 | static inline s64 percpu_counter_read(struct percpu_counter *fbc) |
1da177e4 LT |
62 | { |
63 | return fbc->count; | |
64 | } | |
65 | ||
66 | /* | |
67 | * It is possible for the percpu_counter_read() to return a small negative | |
68 | * number for some counter which should never be negative. | |
0216bfcf | 69 | * |
1da177e4 | 70 | */ |
0216bfcf | 71 | static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) |
1da177e4 | 72 | { |
0216bfcf | 73 | s64 ret = fbc->count; |
1da177e4 LT |
74 | |
75 | barrier(); /* Prevent reloads of fbc->count */ | |
0216bfcf | 76 | if (ret >= 0) |
1da177e4 | 77 | return ret; |
c84598bb | 78 | return 0; |
1da177e4 LT |
79 | } |
80 | ||
7f93cff9 TT |
81 | static inline int percpu_counter_initialized(struct percpu_counter *fbc) |
82 | { | |
83 | return (fbc->counters != NULL); | |
84 | } | |
85 | ||
1da177e4 LT |
86 | #else |
87 | ||
88 | struct percpu_counter { | |
0216bfcf | 89 | s64 count; |
1da177e4 LT |
90 | }; |
91 | ||
833f4077 | 92 | static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount) |
1da177e4 | 93 | { |
0216bfcf | 94 | fbc->count = amount; |
833f4077 | 95 | return 0; |
1da177e4 LT |
96 | } |
97 | ||
98 | static inline void percpu_counter_destroy(struct percpu_counter *fbc) | |
99 | { | |
100 | } | |
101 | ||
3a587f47 PZ |
102 | static inline void percpu_counter_set(struct percpu_counter *fbc, s64 amount) |
103 | { | |
104 | fbc->count = amount; | |
105 | } | |
106 | ||
27f5e0f6 TC |
107 | static inline int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs) |
108 | { | |
109 | if (fbc->count > rhs) | |
110 | return 1; | |
111 | else if (fbc->count < rhs) | |
112 | return -1; | |
113 | else | |
114 | return 0; | |
115 | } | |
116 | ||
1da177e4 | 117 | static inline void |
20e89767 | 118 | percpu_counter_add(struct percpu_counter *fbc, s64 amount) |
1da177e4 LT |
119 | { |
120 | preempt_disable(); | |
121 | fbc->count += amount; | |
122 | preempt_enable(); | |
123 | } | |
124 | ||
0c9cf2ef AB |
125 | static inline void |
126 | __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch) | |
127 | { | |
128 | percpu_counter_add(fbc, amount); | |
129 | } | |
130 | ||
0216bfcf | 131 | static inline s64 percpu_counter_read(struct percpu_counter *fbc) |
1da177e4 LT |
132 | { |
133 | return fbc->count; | |
134 | } | |
135 | ||
c84598bb SL |
136 | /* |
137 | * percpu_counter is intended to track positive numbers. In the UP case the | |
138 | * number should never be negative. | |
139 | */ | |
0216bfcf | 140 | static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) |
1da177e4 LT |
141 | { |
142 | return fbc->count; | |
143 | } | |
144 | ||
52d9f3b4 | 145 | static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc) |
e2bab3d9 AM |
146 | { |
147 | return percpu_counter_read_positive(fbc); | |
148 | } | |
149 | ||
bf1d89c8 PZ |
150 | static inline s64 percpu_counter_sum(struct percpu_counter *fbc) |
151 | { | |
152 | return percpu_counter_read(fbc); | |
153 | } | |
154 | ||
7f93cff9 TT |
155 | static inline int percpu_counter_initialized(struct percpu_counter *fbc) |
156 | { | |
157 | return 1; | |
158 | } | |
159 | ||
1da177e4 LT |
160 | #endif /* CONFIG_SMP */ |
161 | ||
162 | static inline void percpu_counter_inc(struct percpu_counter *fbc) | |
163 | { | |
aa0dff2d | 164 | percpu_counter_add(fbc, 1); |
1da177e4 LT |
165 | } |
166 | ||
167 | static inline void percpu_counter_dec(struct percpu_counter *fbc) | |
168 | { | |
aa0dff2d | 169 | percpu_counter_add(fbc, -1); |
1da177e4 LT |
170 | } |
171 | ||
3cb4f9fa PZ |
172 | static inline void percpu_counter_sub(struct percpu_counter *fbc, s64 amount) |
173 | { | |
174 | percpu_counter_add(fbc, -amount); | |
175 | } | |
176 | ||
1da177e4 | 177 | #endif /* _LINUX_PERCPU_COUNTER_H */ |