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