Green shading in the line number column means the source is part of the translation unit, red means it is conditionally excluded. Highlighted line numbers link to the translation unit page. Highlighted macros link to the macro page.
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: 9: #include <linux/spinlock.h> 10: #include <linux/smp.h> 11: #include <linux/list.h> 12: #include <linux/threads.h> 13: #include <linux/percpu.h> 14: #include <linux/types.h> 15: 16: #ifdef CONFIG_SMP 17: 18: struct percpu_counter { 19: raw_spinlock_t lock; 20: s64 count; 21: #ifdef CONFIG_HOTPLUG_CPU 22: struct list_head list; /* All percpu_counters are on a list */ 23: #endif 24: s32 __percpu *counters; 25: }; 26: 27: extern int percpu_counter_batch; 28: 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: 39: void percpu_counter_destroy(struct percpu_counter *fbc); 40: void percpu_counter_set(struct percpu_counter *fbc, s64 amount); 41: void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch); 42: s64 __percpu_counter_sum(struct percpu_counter *fbc); 43: int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs); 44: 45: static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount) 46: { 47: __percpu_counter_add(fbc, amount, percpu_counter_batch); 48: } 49: 50: static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc) 51: { 52: s64 ret = __percpu_counter_sum(fbc); 53: return ret < 0 ? 0 : ret; 54: } 55: 56: static inline s64 percpu_counter_sum(struct percpu_counter *fbc) 57: { 58: return __percpu_counter_sum(fbc); 59: } 60: 61: static inline s64 percpu_counter_read(struct percpu_counter *fbc) 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. 69: * 70: */ 71: static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) 72: { 73: s64 ret = fbc->count; 74: 75: barrier(); /* Prevent reloads of fbc->count */ 76: if (ret >= 0) 77: return ret; 78: return 0; 79: } 80: 81: static inline int percpu_counter_initialized(struct percpu_counter *fbc) 82: { 83: return (fbc->counters != NULL); 84: } 85: 86: #else /* !CONFIG_SMP */ 87: 88: struct percpu_counter { 89: s64 count; 90: }; 91: 92: static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount) 93: { 94: fbc->count = amount; 95: return 0; 96: } 97: 98: static inline void percpu_counter_destroy(struct percpu_counter *fbc) 99: { 100: } 101: 102: static inline void percpu_counter_set(struct percpu_counter *fbc, s64 amount) 103: { 104: fbc->count = amount; 105: } 106: 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: 117: static inline void 118: percpu_counter_add(struct percpu_counter *fbc, s64 amount) 119: { 120: preempt_disable(); 121: fbc->count += amount; 122: preempt_enable(); 123: } 124: 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: 131: static inline s64 percpu_counter_read(struct percpu_counter *fbc) 132: { 133: return fbc->count; 134: } 135: 136: /* 137: * percpu_counter is intended to track positive numbers. In the UP case the 138: * number should never be negative. 139: */ 140: static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) 141: { 142: return fbc->count; 143: } 144: 145: static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc) 146: { 147: return percpu_counter_read_positive(fbc); 148: } 149: 150: static inline s64 percpu_counter_sum(struct percpu_counter *fbc) 151: { 152: return percpu_counter_read(fbc); 153: } 154: 155: static inline int percpu_counter_initialized(struct percpu_counter *fbc) 156: { 157: return 1; 158: } 159: 160: #endif /* CONFIG_SMP */ 161: 162: static inline void percpu_counter_inc(struct percpu_counter *fbc) 163: { 164: percpu_counter_add(fbc, 1); 165: } 166: 167: static inline void percpu_counter_dec(struct percpu_counter *fbc) 168: { 169: percpu_counter_add(fbc, -1); 170: } 171: 172: static inline void percpu_counter_sub(struct percpu_counter *fbc, s64 amount) 173: { 174: percpu_counter_add(fbc, -amount); 175: } 176: 177: #endif /* _LINUX_PERCPU_COUNTER_H */ 178: