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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * atomics.h
4 : : * Atomic operations.
5 : : *
6 : : * Hardware and compiler dependent functions for manipulating memory
7 : : * atomically and dealing with cache coherency. Used to implement locking
8 : : * facilities and lockless algorithms/data structures.
9 : : *
10 : : * To bring up postgres on a platform/compiler at the very least
11 : : * implementations for the following operations should be provided:
12 : : * * pg_compiler_barrier(), pg_write_barrier(), pg_read_barrier()
13 : : * * pg_atomic_compare_exchange_u32(), pg_atomic_fetch_add_u32()
14 : : * * pg_atomic_test_set_flag(), pg_atomic_init_flag(), pg_atomic_clear_flag()
15 : : * * PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY should be defined if appropriate.
16 : : *
17 : : * There exist generic, hardware independent, implementations for several
18 : : * compilers which might be sufficient, although possibly not optimal, for a
19 : : * new platform. If no such generic implementation is available spinlocks will
20 : : * be used to implement the 64-bit parts of the API.
21 : : *
22 : : * Implement _u64 atomics if and only if your platform can use them
23 : : * efficiently (and obviously correctly).
24 : : *
25 : : * Use higher level functionality (lwlocks, spinlocks, heavyweight locks)
26 : : * whenever possible. Writing correct code using these facilities is hard.
27 : : *
28 : : * For an introduction to using memory barriers within the PostgreSQL backend,
29 : : * see src/backend/storage/lmgr/README.barrier
30 : : *
31 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
32 : : * Portions Copyright (c) 1994, Regents of the University of California
33 : : *
34 : : * src/include/port/atomics.h
35 : : *
36 : : *-------------------------------------------------------------------------
37 : : */
38 : : #ifndef ATOMICS_H
39 : : #define ATOMICS_H
40 : :
41 : : #ifdef FRONTEND
42 : : #error "atomics.h may not be included from frontend code"
43 : : #endif
44 : :
45 : : #define INSIDE_ATOMICS_H
46 : :
47 : : #include <limits.h>
48 : :
49 : : /*
50 : : * First a set of architecture specific files is included.
51 : : *
52 : : * These files can provide the full set of atomics or can do pretty much
53 : : * nothing if all the compilers commonly used on these platforms provide
54 : : * usable generics.
55 : : *
56 : : * Don't add an inline assembly of the actual atomic operations if all the
57 : : * common implementations of your platform provide intrinsics. Intrinsics are
58 : : * much easier to understand and potentially support more architectures.
59 : : *
60 : : * It will often make sense to define memory barrier semantics here, since
61 : : * e.g. generic compiler intrinsics for x86 memory barriers can't know that
62 : : * postgres doesn't need x86 read/write barriers do anything more than a
63 : : * compiler barrier.
64 : : *
65 : : */
66 : : #if defined(__arm__) || defined(__arm) || defined(__aarch64__)
67 : : #include "port/atomics/arch-arm.h"
68 : : #elif defined(__i386__) || defined(__i386) || defined(__x86_64__)
69 : : #include "port/atomics/arch-x86.h"
70 : : #elif defined(__ppc__) || defined(__powerpc__) || defined(__ppc64__) || defined(__powerpc64__)
71 : : #include "port/atomics/arch-ppc.h"
72 : : #endif
73 : :
74 : : /*
75 : : * Compiler specific, but architecture independent implementations.
76 : : *
77 : : * Provide architecture independent implementations of the atomic
78 : : * facilities. At the very least compiler barriers should be provided, but a
79 : : * full implementation of
80 : : * * pg_compiler_barrier(), pg_write_barrier(), pg_read_barrier()
81 : : * * pg_atomic_compare_exchange_u32(), pg_atomic_fetch_add_u32()
82 : : * using compiler intrinsics are a good idea.
83 : : */
84 : : /*
85 : : * gcc or compatible, including clang and icc.
86 : : */
87 : : #if defined(__GNUC__) || defined(__INTEL_COMPILER)
88 : : #include "port/atomics/generic-gcc.h"
89 : : #elif defined(_MSC_VER)
90 : : #include "port/atomics/generic-msvc.h"
91 : : #else
92 : : /* Unknown compiler. */
93 : : #endif
94 : :
95 : : /* Fail if we couldn't find implementations of required facilities. */
96 : : #if !defined(PG_HAVE_ATOMIC_U32_SUPPORT)
97 : : #error "could not find an implementation of pg_atomic_uint32"
98 : : #endif
99 : : #if !defined(pg_compiler_barrier_impl)
100 : : #error "could not find an implementation of pg_compiler_barrier"
101 : : #endif
102 : : #if !defined(pg_memory_barrier_impl)
103 : : #error "could not find an implementation of pg_memory_barrier_impl"
104 : : #endif
105 : :
106 : :
107 : : /*
108 : : * Provide a spinlock-based implementation of the 64 bit variants, if
109 : : * necessary.
110 : : */
111 : : #include "port/atomics/fallback.h"
112 : :
113 : : /*
114 : : * Provide additional operations using supported infrastructure. These are
115 : : * expected to be efficient if the underlying atomic operations are efficient.
116 : : */
117 : : #include "port/atomics/generic.h"
118 : :
119 : :
120 : : /*
121 : : * pg_compiler_barrier - prevent the compiler from moving code across
122 : : *
123 : : * A compiler barrier need not (and preferably should not) emit any actual
124 : : * machine code, but must act as an optimization fence: the compiler must not
125 : : * reorder loads or stores to main memory around the barrier. However, the
126 : : * CPU may still reorder loads or stores at runtime, if the architecture's
127 : : * memory model permits this.
128 : : */
129 : : #define pg_compiler_barrier() pg_compiler_barrier_impl()
130 : :
131 : : /*
132 : : * pg_memory_barrier - prevent the CPU from reordering memory access
133 : : *
134 : : * A memory barrier must act as a compiler barrier, and in addition must
135 : : * guarantee that all loads and stores issued prior to the barrier are
136 : : * completed before any loads or stores issued after the barrier. Unless
137 : : * loads and stores are totally ordered (which is not the case on most
138 : : * architectures) this requires issuing some sort of memory fencing
139 : : * instruction.
140 : : */
141 : : #define pg_memory_barrier() pg_memory_barrier_impl()
142 : :
143 : : /*
144 : : * pg_(read|write)_barrier - prevent the CPU from reordering memory access
145 : : *
146 : : * A read barrier must act as a compiler barrier, and in addition must
147 : : * guarantee that any loads issued prior to the barrier are completed before
148 : : * any loads issued after the barrier. Similarly, a write barrier acts
149 : : * as a compiler barrier, and also orders stores. Read and write barriers
150 : : * are thus weaker than a full memory barrier, but stronger than a compiler
151 : : * barrier. In practice, on machines with strong memory ordering, read and
152 : : * write barriers may require nothing more than a compiler barrier.
153 : : */
154 : : #define pg_read_barrier() pg_read_barrier_impl()
155 : : #define pg_write_barrier() pg_write_barrier_impl()
156 : :
157 : : /*
158 : : * Spinloop delay - Allow CPU to relax in busy loops
159 : : */
160 : : #define pg_spin_delay() pg_spin_delay_impl()
161 : :
162 : : /*
163 : : * pg_atomic_init_flag - initialize atomic flag.
164 : : *
165 : : * No barrier semantics.
166 : : */
167 : : static inline void
168 : 97 : pg_atomic_init_flag(volatile pg_atomic_flag *ptr)
169 : : {
170 : 97 : pg_atomic_init_flag_impl(ptr);
171 : 97 : }
172 : :
173 : : /*
174 : : * pg_atomic_test_set_flag - TAS()
175 : : *
176 : : * Returns true if the flag has successfully been set, false otherwise.
177 : : *
178 : : * Acquire (including read barrier) semantics.
179 : : */
180 : : static inline bool
181 : 3 : pg_atomic_test_set_flag(volatile pg_atomic_flag *ptr)
182 : : {
183 : 3 : return pg_atomic_test_set_flag_impl(ptr);
184 : : }
185 : :
186 : : /*
187 : : * pg_atomic_unlocked_test_flag - Check if the lock is free
188 : : *
189 : : * Returns true if the flag currently is not set, false otherwise.
190 : : *
191 : : * No barrier semantics.
192 : : */
193 : : static inline bool
194 : 3 : pg_atomic_unlocked_test_flag(volatile pg_atomic_flag *ptr)
195 : : {
196 : 3 : return pg_atomic_unlocked_test_flag_impl(ptr);
197 : : }
198 : :
199 : : /*
200 : : * pg_atomic_clear_flag - release lock set by TAS()
201 : : *
202 : : * Release (including write barrier) semantics.
203 : : */
204 : : static inline void
205 : 3 : pg_atomic_clear_flag(volatile pg_atomic_flag *ptr)
206 : : {
207 : 3 : pg_atomic_clear_flag_impl(ptr);
208 : 3 : }
209 : :
210 : :
211 : : /*
212 : : * pg_atomic_init_u32 - initialize atomic variable
213 : : *
214 : : * Has to be done before any concurrent usage..
215 : : *
216 : : * No barrier semantics.
217 : : */
218 : : static inline void
219 : 63843 : pg_atomic_init_u32(volatile pg_atomic_uint32 *ptr, uint32 val)
220 : : {
221 [ + - ]: 63843 : AssertPointerAlignment(ptr, 4);
222 : :
223 : 63843 : pg_atomic_init_u32_impl(ptr, val);
224 : 63843 : }
225 : :
226 : : /*
227 : : * pg_atomic_read_u32 - unlocked read from atomic variable.
228 : : *
229 : : * The read is guaranteed to return a value as it has been written by this or
230 : : * another process at some point in the past. There's however no cache
231 : : * coherency interaction guaranteeing the value hasn't since been written to
232 : : * again.
233 : : *
234 : : * No barrier semantics.
235 : : */
236 : : static inline uint32
237 : 27647981 : pg_atomic_read_u32(volatile pg_atomic_uint32 *ptr)
238 : : {
239 [ + - ]: 27647981 : AssertPointerAlignment(ptr, 4);
240 : 27647981 : return pg_atomic_read_u32_impl(ptr);
241 : : }
242 : :
243 : : /*
244 : : * pg_atomic_read_membarrier_u32 - read with barrier semantics.
245 : : *
246 : : * This read is guaranteed to return the current value, provided that the value
247 : : * is only ever updated via operations with barrier semantics, such as
248 : : * pg_atomic_compare_exchange_u32() and pg_atomic_write_membarrier_u32().
249 : : * While this may be less performant than pg_atomic_read_u32(), it may be
250 : : * easier to reason about correctness with this function in less performance-
251 : : * sensitive code.
252 : : *
253 : : * Full barrier semantics.
254 : : */
255 : : static inline uint32
256 : : pg_atomic_read_membarrier_u32(volatile pg_atomic_uint32 *ptr)
257 : : {
258 : : AssertPointerAlignment(ptr, 4);
259 : :
260 : : return pg_atomic_read_membarrier_u32_impl(ptr);
261 : : }
262 : :
263 : : /*
264 : : * pg_atomic_write_u32 - write to atomic variable.
265 : : *
266 : : * The write is guaranteed to succeed as a whole, i.e. it's not possible to
267 : : * observe a partial write for any reader. Note that this correctly interacts
268 : : * with pg_atomic_compare_exchange_u32, in contrast to
269 : : * pg_atomic_unlocked_write_u32().
270 : : *
271 : : * No barrier semantics.
272 : : */
273 : : static inline void
274 : 2547 : pg_atomic_write_u32(volatile pg_atomic_uint32 *ptr, uint32 val)
275 : : {
276 [ + - ]: 2547 : AssertPointerAlignment(ptr, 4);
277 : :
278 : 2547 : pg_atomic_write_u32_impl(ptr, val);
279 : 2547 : }
280 : :
281 : : /*
282 : : * pg_atomic_unlocked_write_u32 - unlocked write to atomic variable.
283 : : *
284 : : * Write to an atomic variable, without atomicity guarantees. I.e. it is not
285 : : * guaranteed that a concurrent reader will not see a torn value, nor is this
286 : : * guaranteed to correctly interact with concurrent read-modify-write
287 : : * operations like pg_atomic_compare_exchange_u32. This should only be used
288 : : * in cases where minor performance regressions due to atomic operations are
289 : : * unacceptable and where exclusive access is guaranteed via some external
290 : : * means.
291 : : *
292 : : * No barrier semantics.
293 : : */
294 : : static inline void
295 : : pg_atomic_unlocked_write_u32(volatile pg_atomic_uint32 *ptr, uint32 val)
296 : : {
297 : : AssertPointerAlignment(ptr, 4);
298 : :
299 : : pg_atomic_unlocked_write_u32_impl(ptr, val);
300 : : }
301 : :
302 : : /*
303 : : * pg_atomic_write_membarrier_u32 - write with barrier semantics.
304 : : *
305 : : * The write is guaranteed to succeed as a whole, i.e., it's not possible to
306 : : * observe a partial write for any reader. Note that this correctly interacts
307 : : * with both pg_atomic_compare_exchange_u32() and
308 : : * pg_atomic_read_membarrier_u32(). While this may be less performant than
309 : : * pg_atomic_write_u32(), it may be easier to reason about correctness with
310 : : * this function in less performance-sensitive code.
311 : : *
312 : : * Full barrier semantics.
313 : : */
314 : : static inline void
315 : 0 : pg_atomic_write_membarrier_u32(volatile pg_atomic_uint32 *ptr, uint32 val)
316 : : {
317 [ # # ]: 0 : AssertPointerAlignment(ptr, 4);
318 : :
319 : 0 : pg_atomic_write_membarrier_u32_impl(ptr, val);
320 : 0 : }
321 : :
322 : : /*
323 : : * pg_atomic_exchange_u32 - exchange newval with current value
324 : : *
325 : : * Returns the old value of 'ptr' before the swap.
326 : : *
327 : : * Full barrier semantics.
328 : : */
329 : : static inline uint32
330 : 82 : pg_atomic_exchange_u32(volatile pg_atomic_uint32 *ptr, uint32 newval)
331 : : {
332 [ + - ]: 82 : AssertPointerAlignment(ptr, 4);
333 : :
334 : 82 : return pg_atomic_exchange_u32_impl(ptr, newval);
335 : : }
336 : :
337 : : /*
338 : : * pg_atomic_compare_exchange_u32 - CAS operation
339 : : *
340 : : * Atomically compare the current value of ptr with *expected and store newval
341 : : * iff ptr and *expected have the same value. The current value of *ptr will
342 : : * always be stored in *expected.
343 : : *
344 : : * Return true if values have been exchanged, false otherwise.
345 : : *
346 : : * Full barrier semantics.
347 : : */
348 : : static inline bool
349 : 27267107 : pg_atomic_compare_exchange_u32(volatile pg_atomic_uint32 *ptr,
350 : : uint32 *expected, uint32 newval)
351 : : {
352 [ + - ]: 27267107 : AssertPointerAlignment(ptr, 4);
353 [ + - ]: 27267107 : AssertPointerAlignment(expected, 4);
354 : :
355 : 27267107 : return pg_atomic_compare_exchange_u32_impl(ptr, expected, newval);
356 : : }
357 : :
358 : : /*
359 : : * pg_atomic_fetch_add_u32 - atomically add to variable
360 : : *
361 : : * Returns the value of ptr before the arithmetic operation.
362 : : *
363 : : * Full barrier semantics.
364 : : */
365 : : static inline uint32
366 : 156637 : pg_atomic_fetch_add_u32(volatile pg_atomic_uint32 *ptr, int32 add_)
367 : : {
368 [ + - ]: 156637 : AssertPointerAlignment(ptr, 4);
369 : 156637 : return pg_atomic_fetch_add_u32_impl(ptr, add_);
370 : : }
371 : :
372 : : /*
373 : : * pg_atomic_fetch_sub_u32 - atomically subtract from variable
374 : : *
375 : : * Returns the value of ptr before the arithmetic operation. Note that sub_
376 : : * may not be INT_MIN due to platform limitations.
377 : : *
378 : : * Full barrier semantics.
379 : : */
380 : : static inline uint32
381 : 49415 : pg_atomic_fetch_sub_u32(volatile pg_atomic_uint32 *ptr, int32 sub_)
382 : : {
383 [ + - ]: 49415 : AssertPointerAlignment(ptr, 4);
384 [ + - ]: 49415 : Assert(sub_ != INT_MIN);
385 : 49415 : return pg_atomic_fetch_sub_u32_impl(ptr, sub_);
386 : : }
387 : :
388 : : /*
389 : : * pg_atomic_fetch_and_u32 - atomically bit-and and_ with variable
390 : : *
391 : : * Returns the value of ptr before the arithmetic operation.
392 : : *
393 : : * Full barrier semantics.
394 : : */
395 : : static inline uint32
396 : 41505 : pg_atomic_fetch_and_u32(volatile pg_atomic_uint32 *ptr, uint32 and_)
397 : : {
398 [ + - ]: 41505 : AssertPointerAlignment(ptr, 4);
399 : 41505 : return pg_atomic_fetch_and_u32_impl(ptr, and_);
400 : : }
401 : :
402 : : /*
403 : : * pg_atomic_fetch_or_u32 - atomically bit-or or_ with variable
404 : : *
405 : : * Returns the value of ptr before the arithmetic operation.
406 : : *
407 : : * Full barrier semantics.
408 : : */
409 : : static inline uint32
410 : 47615 : pg_atomic_fetch_or_u32(volatile pg_atomic_uint32 *ptr, uint32 or_)
411 : : {
412 [ + - ]: 47615 : AssertPointerAlignment(ptr, 4);
413 : 47615 : return pg_atomic_fetch_or_u32_impl(ptr, or_);
414 : : }
415 : :
416 : : /*
417 : : * pg_atomic_add_fetch_u32 - atomically add to variable
418 : : *
419 : : * Returns the value of ptr after the arithmetic operation.
420 : : *
421 : : * Full barrier semantics.
422 : : */
423 : : static inline uint32
424 : 61 : pg_atomic_add_fetch_u32(volatile pg_atomic_uint32 *ptr, int32 add_)
425 : : {
426 [ + - ]: 61 : AssertPointerAlignment(ptr, 4);
427 : 61 : return pg_atomic_add_fetch_u32_impl(ptr, add_);
428 : : }
429 : :
430 : : /*
431 : : * pg_atomic_sub_fetch_u32 - atomically subtract from variable
432 : : *
433 : : * Returns the value of ptr after the arithmetic operation. Note that sub_ may
434 : : * not be INT_MIN due to platform limitations.
435 : : *
436 : : * Full barrier semantics.
437 : : */
438 : : static inline uint32
439 : 27256915 : pg_atomic_sub_fetch_u32(volatile pg_atomic_uint32 *ptr, int32 sub_)
440 : : {
441 [ + - ]: 27256915 : AssertPointerAlignment(ptr, 4);
442 [ + - ]: 27256915 : Assert(sub_ != INT_MIN);
443 : 27256915 : return pg_atomic_sub_fetch_u32_impl(ptr, sub_);
444 : : }
445 : :
446 : : /* ----
447 : : * The 64 bit operations have the same semantics as their 32bit counterparts
448 : : * if they are available. Check the corresponding 32bit function for
449 : : * documentation.
450 : : * ----
451 : : */
452 : : static inline void
453 : 89837 : pg_atomic_init_u64(volatile pg_atomic_uint64 *ptr, uint64 val)
454 : : {
455 : : /*
456 : : * Can't necessarily enforce alignment - and don't need it - when using
457 : : * the spinlock based fallback implementation. Therefore only assert when
458 : : * not using it.
459 : : */
460 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
461 [ + - ]: 89837 : AssertPointerAlignment(ptr, 8);
462 : : #endif
463 : 89837 : pg_atomic_init_u64_impl(ptr, val);
464 : 89837 : }
465 : :
466 : : static inline uint64
467 : 65514801 : pg_atomic_read_u64(volatile pg_atomic_uint64 *ptr)
468 : : {
469 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
470 [ + - ]: 65514801 : AssertPointerAlignment(ptr, 8);
471 : : #endif
472 : 65514801 : return pg_atomic_read_u64_impl(ptr);
473 : : }
474 : :
475 : : static inline uint64
476 : 24101 : pg_atomic_read_membarrier_u64(volatile pg_atomic_uint64 *ptr)
477 : : {
478 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
479 [ + - ]: 24101 : AssertPointerAlignment(ptr, 8);
480 : : #endif
481 : 24101 : return pg_atomic_read_membarrier_u64_impl(ptr);
482 : : }
483 : :
484 : : static inline void
485 : 114649 : pg_atomic_write_u64(volatile pg_atomic_uint64 *ptr, uint64 val)
486 : : {
487 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
488 [ + - ]: 114649 : AssertPointerAlignment(ptr, 8);
489 : : #endif
490 : 114649 : pg_atomic_write_u64_impl(ptr, val);
491 : 114649 : }
492 : :
493 : : static inline void
494 : 1238602 : pg_atomic_unlocked_write_u64(volatile pg_atomic_uint64 *ptr, uint64 val)
495 : : {
496 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
497 [ + - ]: 1238602 : AssertPointerAlignment(ptr, 8);
498 : : #endif
499 : :
500 : 1238602 : pg_atomic_unlocked_write_u64_impl(ptr, val);
501 : 1238602 : }
502 : :
503 : : static inline void
504 : 4 : pg_atomic_write_membarrier_u64(volatile pg_atomic_uint64 *ptr, uint64 val)
505 : : {
506 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
507 [ + - ]: 4 : AssertPointerAlignment(ptr, 8);
508 : : #endif
509 : 4 : pg_atomic_write_membarrier_u64_impl(ptr, val);
510 : 4 : }
511 : :
512 : : static inline uint64
513 : 2557271 : pg_atomic_exchange_u64(volatile pg_atomic_uint64 *ptr, uint64 newval)
514 : : {
515 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
516 [ + - ]: 2557271 : AssertPointerAlignment(ptr, 8);
517 : : #endif
518 : 2557271 : return pg_atomic_exchange_u64_impl(ptr, newval);
519 : : }
520 : :
521 : : static inline bool
522 : 29751329 : pg_atomic_compare_exchange_u64(volatile pg_atomic_uint64 *ptr,
523 : : uint64 *expected, uint64 newval)
524 : : {
525 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
526 [ + - ]: 29751329 : AssertPointerAlignment(ptr, 8);
527 : : #endif
528 : 29751329 : return pg_atomic_compare_exchange_u64_impl(ptr, expected, newval);
529 : : }
530 : :
531 : : static inline uint64
532 : 30529 : pg_atomic_fetch_add_u64(volatile pg_atomic_uint64 *ptr, int64 add_)
533 : : {
534 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
535 [ + - ]: 30529 : AssertPointerAlignment(ptr, 8);
536 : : #endif
537 : 30529 : return pg_atomic_fetch_add_u64_impl(ptr, add_);
538 : : }
539 : :
540 : : static inline uint64
541 : 11623996 : pg_atomic_fetch_sub_u64(volatile pg_atomic_uint64 *ptr, int64 sub_)
542 : : {
543 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
544 [ + - ]: 11623996 : AssertPointerAlignment(ptr, 8);
545 : : #endif
546 [ + - ]: 11623996 : Assert(sub_ != PG_INT64_MIN);
547 : 11623996 : return pg_atomic_fetch_sub_u64_impl(ptr, sub_);
548 : : }
549 : :
550 : : static inline uint64
551 : 1943 : pg_atomic_fetch_and_u64(volatile pg_atomic_uint64 *ptr, uint64 and_)
552 : : {
553 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
554 [ + - ]: 1943 : AssertPointerAlignment(ptr, 8);
555 : : #endif
556 : 1943 : return pg_atomic_fetch_and_u64_impl(ptr, and_);
557 : : }
558 : :
559 : : static inline uint64
560 : 1281572 : pg_atomic_fetch_or_u64(volatile pg_atomic_uint64 *ptr, uint64 or_)
561 : : {
562 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
563 [ + - ]: 1281572 : AssertPointerAlignment(ptr, 8);
564 : : #endif
565 : 1281572 : return pg_atomic_fetch_or_u64_impl(ptr, or_);
566 : : }
567 : :
568 : : static inline uint64
569 : 7 : pg_atomic_add_fetch_u64(volatile pg_atomic_uint64 *ptr, int64 add_)
570 : : {
571 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
572 [ + - ]: 7 : AssertPointerAlignment(ptr, 8);
573 : : #endif
574 : 7 : return pg_atomic_add_fetch_u64_impl(ptr, add_);
575 : : }
576 : :
577 : : static inline uint64
578 : 15321272 : pg_atomic_sub_fetch_u64(volatile pg_atomic_uint64 *ptr, int64 sub_)
579 : : {
580 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
581 [ + - ]: 15321272 : AssertPointerAlignment(ptr, 8);
582 : : #endif
583 [ + - ]: 15321272 : Assert(sub_ != PG_INT64_MIN);
584 : 15321272 : return pg_atomic_sub_fetch_u64_impl(ptr, sub_);
585 : : }
586 : :
587 : : /*
588 : : * Monotonically advance the given variable using only atomic operations until
589 : : * it's at least the target value. Returns the latest value observed, which
590 : : * may or may not be the target value.
591 : : *
592 : : * Full barrier semantics (even when value is unchanged).
593 : : */
594 : : static inline uint64
595 : 20055 : pg_atomic_monotonic_advance_u64(volatile pg_atomic_uint64 *ptr, uint64 target)
596 : : {
597 : 20055 : uint64 currval;
598 : :
599 : : #ifndef PG_HAVE_ATOMIC_U64_SIMULATION
600 [ + - ]: 20055 : AssertPointerAlignment(ptr, 8);
601 : : #endif
602 : :
603 : 20055 : currval = pg_atomic_read_u64_impl(ptr);
604 [ + + ]: 20055 : if (currval >= target)
605 : : {
606 : 284 : pg_memory_barrier();
607 : 284 : return currval;
608 : : }
609 : :
610 [ + + ]: 19773 : while (currval < target)
611 : : {
612 [ + + ]: 19771 : if (pg_atomic_compare_exchange_u64(ptr, &currval, target))
613 : 19769 : return target;
614 : : }
615 : :
616 : 2 : return currval;
617 : 20055 : }
618 : :
619 : : #undef INSIDE_ATOMICS_H
620 : :
621 : : #endif /* ATOMICS_H */
|
