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1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
2 | * | |
3 | * counter/counter-api.h | |
4 | * | |
5 | * LTTng Counters API, requiring counter/config.h | |
6 | * | |
7 | * Copyright (C) 2020 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | */ | |
9 | ||
10 | #ifndef _LTTNG_COUNTER_API_H | |
11 | #define _LTTNG_COUNTER_API_H | |
12 | ||
13 | #include <linux/types.h> | |
14 | #include <linux/percpu.h> | |
15 | #include <linux/bitops.h> | |
16 | #include <counter/counter.h> | |
17 | #include <counter/counter-internal.h> | |
236233f7 | 18 | #include <wrapper/limits.h> |
a101fa10 MD |
19 | |
20 | /* | |
21 | * Using unsigned arithmetic because overflow is defined. | |
22 | */ | |
23 | static inline int __lttng_counter_add(const struct lib_counter_config *config, | |
24 | enum lib_counter_config_alloc alloc, | |
25 | enum lib_counter_config_sync sync, | |
26 | struct lib_counter *counter, | |
27 | const size_t *dimension_indexes, int64_t v, | |
28 | int64_t *remainder) | |
29 | { | |
30 | size_t index; | |
31 | bool overflow = false, underflow = false; | |
32 | struct lib_counter_layout *layout; | |
33 | int64_t move_sum = 0; | |
34 | ||
35 | if (unlikely(lttng_counter_validate_indexes(config, counter, dimension_indexes))) | |
36 | return -EOVERFLOW; | |
37 | index = lttng_counter_get_index(config, counter, dimension_indexes); | |
38 | ||
39 | switch (alloc) { | |
40 | case COUNTER_ALLOC_PER_CPU: | |
41 | layout = per_cpu_ptr(counter->percpu_counters, smp_processor_id()); | |
42 | break; | |
43 | case COUNTER_ALLOC_GLOBAL: | |
44 | layout = &counter->global_counters; | |
45 | break; | |
46 | default: | |
47 | return -EINVAL; | |
48 | } | |
49 | ||
50 | switch (config->counter_size) { | |
51 | case COUNTER_SIZE_8_BIT: | |
52 | { | |
53 | int8_t *int_p = (int8_t *) layout->counters + index; | |
54 | int8_t old, n, res; | |
55 | int8_t global_sum_step = counter->global_sum_step.s8; | |
56 | ||
57 | res = *int_p; | |
58 | switch (sync) { | |
59 | case COUNTER_SYNC_PER_CPU: | |
60 | { | |
61 | do { | |
62 | move_sum = 0; | |
63 | old = res; | |
64 | n = (int8_t) ((uint8_t) old + (uint8_t) v); | |
65 | if (unlikely(n > (int8_t) global_sum_step)) | |
66 | move_sum = (int8_t) global_sum_step / 2; | |
67 | else if (unlikely(n < -(int8_t) global_sum_step)) | |
68 | move_sum = -((int8_t) global_sum_step / 2); | |
69 | n -= move_sum; | |
70 | res = cmpxchg_local(int_p, old, n); | |
71 | } while (old != res); | |
72 | break; | |
73 | } | |
74 | case COUNTER_SYNC_GLOBAL: | |
75 | { | |
76 | do { | |
77 | old = res; | |
78 | n = (int8_t) ((uint8_t) old + (uint8_t) v); | |
79 | res = cmpxchg(int_p, old, n); | |
80 | } while (old != res); | |
81 | break; | |
82 | } | |
83 | } | |
84 | if (v > 0 && (v >= U8_MAX || n < old)) | |
85 | overflow = true; | |
86 | else if (v < 0 && (v <= -U8_MAX || n > old)) | |
87 | underflow = true; | |
88 | break; | |
89 | } | |
90 | case COUNTER_SIZE_16_BIT: | |
91 | { | |
92 | int16_t *int_p = (int16_t *) layout->counters + index; | |
93 | int16_t old, n, res; | |
94 | int16_t global_sum_step = counter->global_sum_step.s16; | |
95 | ||
96 | res = *int_p; | |
97 | switch (sync) { | |
98 | case COUNTER_SYNC_PER_CPU: | |
99 | { | |
100 | do { | |
101 | move_sum = 0; | |
102 | old = res; | |
103 | n = (int16_t) ((uint16_t) old + (uint16_t) v); | |
104 | if (unlikely(n > (int16_t) global_sum_step)) | |
105 | move_sum = (int16_t) global_sum_step / 2; | |
106 | else if (unlikely(n < -(int16_t) global_sum_step)) | |
107 | move_sum = -((int16_t) global_sum_step / 2); | |
108 | n -= move_sum; | |
109 | res = cmpxchg_local(int_p, old, n); | |
110 | } while (old != res); | |
111 | break; | |
112 | } | |
113 | case COUNTER_SYNC_GLOBAL: | |
114 | { | |
115 | do { | |
116 | old = res; | |
117 | n = (int16_t) ((uint16_t) old + (uint16_t) v); | |
118 | res = cmpxchg(int_p, old, n); | |
119 | } while (old != res); | |
120 | break; | |
121 | } | |
122 | } | |
123 | if (v > 0 && (v >= U16_MAX || n < old)) | |
124 | overflow = true; | |
125 | else if (v < 0 && (v <= -U16_MAX || n > old)) | |
126 | underflow = true; | |
127 | break; | |
128 | } | |
129 | case COUNTER_SIZE_32_BIT: | |
130 | { | |
131 | int32_t *int_p = (int32_t *) layout->counters + index; | |
132 | int32_t old, n, res; | |
133 | int32_t global_sum_step = counter->global_sum_step.s32; | |
134 | ||
135 | res = *int_p; | |
136 | switch (sync) { | |
137 | case COUNTER_SYNC_PER_CPU: | |
138 | { | |
139 | do { | |
140 | move_sum = 0; | |
141 | old = res; | |
142 | n = (int32_t) ((uint32_t) old + (uint32_t) v); | |
143 | if (unlikely(n > (int32_t) global_sum_step)) | |
144 | move_sum = (int32_t) global_sum_step / 2; | |
145 | else if (unlikely(n < -(int32_t) global_sum_step)) | |
146 | move_sum = -((int32_t) global_sum_step / 2); | |
147 | n -= move_sum; | |
148 | res = cmpxchg_local(int_p, old, n); | |
149 | } while (old != res); | |
150 | break; | |
151 | } | |
152 | case COUNTER_SYNC_GLOBAL: | |
153 | { | |
154 | do { | |
155 | old = res; | |
156 | n = (int32_t) ((uint32_t) old + (uint32_t) v); | |
157 | res = cmpxchg(int_p, old, n); | |
158 | } while (old != res); | |
159 | break; | |
160 | } | |
161 | } | |
162 | if (v > 0 && (v >= U32_MAX || n < old)) | |
163 | overflow = true; | |
164 | else if (v < 0 && (v <= -U32_MAX || n > old)) | |
165 | underflow = true; | |
166 | break; | |
167 | } | |
168 | #if BITS_PER_LONG == 64 | |
169 | case COUNTER_SIZE_64_BIT: | |
170 | { | |
171 | int64_t *int_p = (int64_t *) layout->counters + index; | |
172 | int64_t old, n, res; | |
173 | int64_t global_sum_step = counter->global_sum_step.s64; | |
174 | ||
175 | res = *int_p; | |
176 | switch (sync) { | |
177 | case COUNTER_SYNC_PER_CPU: | |
178 | { | |
179 | do { | |
180 | move_sum = 0; | |
181 | old = res; | |
182 | n = (int64_t) ((uint64_t) old + (uint64_t) v); | |
183 | if (unlikely(n > (int64_t) global_sum_step)) | |
184 | move_sum = (int64_t) global_sum_step / 2; | |
185 | else if (unlikely(n < -(int64_t) global_sum_step)) | |
186 | move_sum = -((int64_t) global_sum_step / 2); | |
187 | n -= move_sum; | |
188 | res = cmpxchg_local(int_p, old, n); | |
189 | } while (old != res); | |
190 | break; | |
191 | } | |
192 | case COUNTER_SYNC_GLOBAL: | |
193 | { | |
194 | do { | |
195 | old = res; | |
196 | n = (int64_t) ((uint64_t) old + (uint64_t) v); | |
197 | res = cmpxchg(int_p, old, n); | |
198 | } while (old != res); | |
199 | break; | |
200 | } | |
201 | } | |
202 | if (v > 0 && n < old) | |
203 | overflow = true; | |
204 | else if (v < 0 && n > old) | |
205 | underflow = true; | |
206 | break; | |
207 | } | |
208 | #endif | |
209 | default: | |
210 | return -EINVAL; | |
211 | } | |
212 | if (unlikely(overflow && !test_bit(index, layout->overflow_bitmap))) | |
213 | set_bit(index, layout->overflow_bitmap); | |
214 | else if (unlikely(underflow && !test_bit(index, layout->underflow_bitmap))) | |
215 | set_bit(index, layout->underflow_bitmap); | |
216 | if (remainder) | |
217 | *remainder = move_sum; | |
218 | return 0; | |
219 | } | |
220 | ||
221 | static inline int __lttng_counter_add_percpu(const struct lib_counter_config *config, | |
222 | struct lib_counter *counter, | |
223 | const size_t *dimension_indexes, int64_t v) | |
224 | { | |
225 | int64_t move_sum; | |
226 | int ret; | |
227 | ||
228 | ret = __lttng_counter_add(config, COUNTER_ALLOC_PER_CPU, config->sync, | |
229 | counter, dimension_indexes, v, &move_sum); | |
230 | if (unlikely(ret)) | |
231 | return ret; | |
232 | if (unlikely(move_sum)) | |
233 | return __lttng_counter_add(config, COUNTER_ALLOC_GLOBAL, COUNTER_SYNC_GLOBAL, | |
234 | counter, dimension_indexes, move_sum, NULL); | |
235 | return 0; | |
236 | } | |
237 | ||
238 | static inline int __lttng_counter_add_global(const struct lib_counter_config *config, | |
239 | struct lib_counter *counter, | |
240 | const size_t *dimension_indexes, int64_t v) | |
241 | { | |
242 | return __lttng_counter_add(config, COUNTER_ALLOC_GLOBAL, config->sync, counter, | |
243 | dimension_indexes, v, NULL); | |
244 | } | |
245 | ||
246 | static inline int lttng_counter_add(const struct lib_counter_config *config, | |
247 | struct lib_counter *counter, | |
248 | const size_t *dimension_indexes, int64_t v) | |
249 | { | |
250 | switch (config->alloc) { | |
251 | case COUNTER_ALLOC_PER_CPU: /* Fallthrough */ | |
252 | case COUNTER_ALLOC_PER_CPU | COUNTER_ALLOC_GLOBAL: | |
253 | return __lttng_counter_add_percpu(config, counter, dimension_indexes, v); | |
254 | case COUNTER_ALLOC_GLOBAL: | |
255 | return __lttng_counter_add_global(config, counter, dimension_indexes, v); | |
256 | default: | |
257 | return -EINVAL; | |
258 | } | |
259 | } | |
260 | ||
261 | static inline int lttng_counter_inc(const struct lib_counter_config *config, | |
262 | struct lib_counter *counter, | |
263 | const size_t *dimension_indexes) | |
264 | { | |
265 | return lttng_counter_add(config, counter, dimension_indexes, 1); | |
266 | } | |
267 | ||
268 | static inline int lttng_counter_dec(const struct lib_counter_config *config, | |
269 | struct lib_counter *counter, | |
270 | const size_t *dimension_indexes) | |
271 | { | |
272 | return lttng_counter_add(config, counter, dimension_indexes, -1); | |
273 | } | |
274 | ||
275 | #endif /* _LTTNG_COUNTER_API_H */ |