Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * mcxt.c
4 : * POSTGRES memory context management code.
5 : *
6 : * This module handles context management operations that are independent
7 : * of the particular kind of context being operated on. It calls
8 : * context-type-specific operations via the function pointers in a
9 : * context's MemoryContextMethods struct.
10 : *
11 : * A note about Valgrind support: when USE_VALGRIND is defined, we provide
12 : * support for memory leak tracking at the allocation-unit level. Valgrind
13 : * does leak detection by tracking allocated "chunks", which can be grouped
14 : * into "pools". The "chunk" terminology is overloaded, since we use that
15 : * word for our allocation units, and it's sometimes important to distinguish
16 : * those from the Valgrind objects that describe them. To reduce confusion,
17 : * let's use the terms "vchunk" and "vpool" for the Valgrind objects.
18 : *
19 : * We use a separate vpool for each memory context. The context-type-specific
20 : * code is responsible for creating and deleting the vpools, and also for
21 : * creating vchunks to cover its management data structures such as block
22 : * headers. (There must be a vchunk that includes every pointer we want
23 : * Valgrind to consider for leak-tracking purposes.) This module creates
24 : * and deletes the vchunks that cover the caller-visible allocated chunks.
25 : * However, the context-type-specific code must handle cleaning up those
26 : * vchunks too during memory context reset operations.
27 : *
28 : *
29 : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
30 : * Portions Copyright (c) 1994, Regents of the University of California
31 : *
32 : *
33 : * IDENTIFICATION
34 : * src/backend/utils/mmgr/mcxt.c
35 : *
36 : *-------------------------------------------------------------------------
37 : */
38 :
39 : #include "postgres.h"
40 :
41 : #include "mb/pg_wchar.h"
42 : #include "miscadmin.h"
43 : #include "utils/memdebug.h"
44 : #include "utils/memutils.h"
45 : #include "utils/memutils_internal.h"
46 : #include "utils/memutils_memorychunk.h"
47 :
48 :
49 : static void BogusFree(void *pointer);
50 : static void *BogusRealloc(void *pointer, Size size, int flags);
51 : static MemoryContext BogusGetChunkContext(void *pointer);
52 : static Size BogusGetChunkSpace(void *pointer);
53 :
54 : /*****************************************************************************
55 : * GLOBAL MEMORY *
56 : *****************************************************************************/
57 : #define BOGUS_MCTX(id) \
58 : [id].free_p = BogusFree, \
59 : [id].realloc = BogusRealloc, \
60 : [id].get_chunk_context = BogusGetChunkContext, \
61 : [id].get_chunk_space = BogusGetChunkSpace
62 :
63 : static const MemoryContextMethods mcxt_methods[] = {
64 : /* aset.c */
65 : [MCTX_ASET_ID].alloc = AllocSetAlloc,
66 : [MCTX_ASET_ID].free_p = AllocSetFree,
67 : [MCTX_ASET_ID].realloc = AllocSetRealloc,
68 : [MCTX_ASET_ID].reset = AllocSetReset,
69 : [MCTX_ASET_ID].delete_context = AllocSetDelete,
70 : [MCTX_ASET_ID].get_chunk_context = AllocSetGetChunkContext,
71 : [MCTX_ASET_ID].get_chunk_space = AllocSetGetChunkSpace,
72 : [MCTX_ASET_ID].is_empty = AllocSetIsEmpty,
73 : [MCTX_ASET_ID].stats = AllocSetStats,
74 : #ifdef MEMORY_CONTEXT_CHECKING
75 : [MCTX_ASET_ID].check = AllocSetCheck,
76 : #endif
77 :
78 : /* generation.c */
79 : [MCTX_GENERATION_ID].alloc = GenerationAlloc,
80 : [MCTX_GENERATION_ID].free_p = GenerationFree,
81 : [MCTX_GENERATION_ID].realloc = GenerationRealloc,
82 : [MCTX_GENERATION_ID].reset = GenerationReset,
83 : [MCTX_GENERATION_ID].delete_context = GenerationDelete,
84 : [MCTX_GENERATION_ID].get_chunk_context = GenerationGetChunkContext,
85 : [MCTX_GENERATION_ID].get_chunk_space = GenerationGetChunkSpace,
86 : [MCTX_GENERATION_ID].is_empty = GenerationIsEmpty,
87 : [MCTX_GENERATION_ID].stats = GenerationStats,
88 : #ifdef MEMORY_CONTEXT_CHECKING
89 : [MCTX_GENERATION_ID].check = GenerationCheck,
90 : #endif
91 :
92 : /* slab.c */
93 : [MCTX_SLAB_ID].alloc = SlabAlloc,
94 : [MCTX_SLAB_ID].free_p = SlabFree,
95 : [MCTX_SLAB_ID].realloc = SlabRealloc,
96 : [MCTX_SLAB_ID].reset = SlabReset,
97 : [MCTX_SLAB_ID].delete_context = SlabDelete,
98 : [MCTX_SLAB_ID].get_chunk_context = SlabGetChunkContext,
99 : [MCTX_SLAB_ID].get_chunk_space = SlabGetChunkSpace,
100 : [MCTX_SLAB_ID].is_empty = SlabIsEmpty,
101 : [MCTX_SLAB_ID].stats = SlabStats,
102 : #ifdef MEMORY_CONTEXT_CHECKING
103 : [MCTX_SLAB_ID].check = SlabCheck,
104 : #endif
105 :
106 : /* alignedalloc.c */
107 : [MCTX_ALIGNED_REDIRECT_ID].alloc = NULL, /* not required */
108 : [MCTX_ALIGNED_REDIRECT_ID].free_p = AlignedAllocFree,
109 : [MCTX_ALIGNED_REDIRECT_ID].realloc = AlignedAllocRealloc,
110 : [MCTX_ALIGNED_REDIRECT_ID].reset = NULL, /* not required */
111 : [MCTX_ALIGNED_REDIRECT_ID].delete_context = NULL, /* not required */
112 : [MCTX_ALIGNED_REDIRECT_ID].get_chunk_context = AlignedAllocGetChunkContext,
113 : [MCTX_ALIGNED_REDIRECT_ID].get_chunk_space = AlignedAllocGetChunkSpace,
114 : [MCTX_ALIGNED_REDIRECT_ID].is_empty = NULL, /* not required */
115 : [MCTX_ALIGNED_REDIRECT_ID].stats = NULL, /* not required */
116 : #ifdef MEMORY_CONTEXT_CHECKING
117 : [MCTX_ALIGNED_REDIRECT_ID].check = NULL, /* not required */
118 : #endif
119 :
120 : /* bump.c */
121 : [MCTX_BUMP_ID].alloc = BumpAlloc,
122 : [MCTX_BUMP_ID].free_p = BumpFree,
123 : [MCTX_BUMP_ID].realloc = BumpRealloc,
124 : [MCTX_BUMP_ID].reset = BumpReset,
125 : [MCTX_BUMP_ID].delete_context = BumpDelete,
126 : [MCTX_BUMP_ID].get_chunk_context = BumpGetChunkContext,
127 : [MCTX_BUMP_ID].get_chunk_space = BumpGetChunkSpace,
128 : [MCTX_BUMP_ID].is_empty = BumpIsEmpty,
129 : [MCTX_BUMP_ID].stats = BumpStats,
130 : #ifdef MEMORY_CONTEXT_CHECKING
131 : [MCTX_BUMP_ID].check = BumpCheck,
132 : #endif
133 :
134 :
135 : /*
136 : * Reserved and unused IDs should have dummy entries here. This allows us
137 : * to fail cleanly if a bogus pointer is passed to pfree or the like. It
138 : * seems sufficient to provide routines for the methods that might get
139 : * invoked from inspection of a chunk (see MCXT_METHOD calls below).
140 : */
141 : BOGUS_MCTX(MCTX_1_RESERVED_GLIBC_ID),
142 : BOGUS_MCTX(MCTX_2_RESERVED_GLIBC_ID),
143 : BOGUS_MCTX(MCTX_8_UNUSED_ID),
144 : BOGUS_MCTX(MCTX_9_UNUSED_ID),
145 : BOGUS_MCTX(MCTX_10_UNUSED_ID),
146 : BOGUS_MCTX(MCTX_11_UNUSED_ID),
147 : BOGUS_MCTX(MCTX_12_UNUSED_ID),
148 : BOGUS_MCTX(MCTX_13_UNUSED_ID),
149 : BOGUS_MCTX(MCTX_14_UNUSED_ID),
150 : BOGUS_MCTX(MCTX_0_RESERVED_UNUSEDMEM_ID),
151 : BOGUS_MCTX(MCTX_15_RESERVED_WIPEDMEM_ID)
152 : };
153 :
154 : #undef BOGUS_MCTX
155 :
156 : /*
157 : * CurrentMemoryContext
158 : * Default memory context for allocations.
159 : */
160 : MemoryContext CurrentMemoryContext = NULL;
161 :
162 : /*
163 : * Standard top-level contexts. For a description of the purpose of each
164 : * of these contexts, refer to src/backend/utils/mmgr/README
165 : */
166 : MemoryContext TopMemoryContext = NULL;
167 : MemoryContext ErrorContext = NULL;
168 : MemoryContext PostmasterContext = NULL;
169 : MemoryContext CacheMemoryContext = NULL;
170 : MemoryContext MessageContext = NULL;
171 : MemoryContext TopTransactionContext = NULL;
172 : MemoryContext CurTransactionContext = NULL;
173 :
174 : /* This is a transient link to the active portal's memory context: */
175 : MemoryContext PortalContext = NULL;
176 :
177 : /* Is memory context logging currently in progress? */
178 : static bool LogMemoryContextInProgress = false;
179 :
180 : static void MemoryContextDeleteOnly(MemoryContext context);
181 : static void MemoryContextCallResetCallbacks(MemoryContext context);
182 : static void MemoryContextStatsInternal(MemoryContext context, int level,
183 : int max_level, int max_children,
184 : MemoryContextCounters *totals,
185 : bool print_to_stderr);
186 : static void MemoryContextStatsPrint(MemoryContext context, void *passthru,
187 : const char *stats_string,
188 : bool print_to_stderr);
189 :
190 : /*
191 : * You should not do memory allocations within a critical section, because
192 : * an out-of-memory error will be escalated to a PANIC. To enforce that
193 : * rule, the allocation functions Assert that.
194 : */
195 : #define AssertNotInCriticalSection(context) \
196 : Assert(CritSectionCount == 0 || (context)->allowInCritSection)
197 :
198 : /*
199 : * Call the given function in the MemoryContextMethods for the memory context
200 : * type that 'pointer' belongs to.
201 : */
202 : #define MCXT_METHOD(pointer, method) \
203 : mcxt_methods[GetMemoryChunkMethodID(pointer)].method
204 :
205 : /*
206 : * GetMemoryChunkMethodID
207 : * Return the MemoryContextMethodID from the uint64 chunk header which
208 : * directly precedes 'pointer'.
209 : */
210 : static inline MemoryContextMethodID
211 572479328 : GetMemoryChunkMethodID(const void *pointer)
212 : {
213 : uint64 header;
214 :
215 : /*
216 : * Try to detect bogus pointers handed to us, poorly though we can.
217 : * Presumably, a pointer that isn't MAXALIGNED isn't pointing at an
218 : * allocated chunk.
219 : */
220 : Assert(pointer == (const void *) MAXALIGN(pointer));
221 :
222 : /* Allow access to the uint64 header */
223 : VALGRIND_MAKE_MEM_DEFINED((char *) pointer - sizeof(uint64), sizeof(uint64));
224 :
225 572479328 : header = *((const uint64 *) ((const char *) pointer - sizeof(uint64)));
226 :
227 : /* Disallow access to the uint64 header */
228 : VALGRIND_MAKE_MEM_NOACCESS((char *) pointer - sizeof(uint64), sizeof(uint64));
229 :
230 572479328 : return (MemoryContextMethodID) (header & MEMORY_CONTEXT_METHODID_MASK);
231 : }
232 :
233 : /*
234 : * GetMemoryChunkHeader
235 : * Return the uint64 chunk header which directly precedes 'pointer'.
236 : *
237 : * This is only used after GetMemoryChunkMethodID, so no need for error checks.
238 : */
239 : static inline uint64
240 0 : GetMemoryChunkHeader(const void *pointer)
241 : {
242 : uint64 header;
243 :
244 : /* Allow access to the uint64 header */
245 : VALGRIND_MAKE_MEM_DEFINED((char *) pointer - sizeof(uint64), sizeof(uint64));
246 :
247 0 : header = *((const uint64 *) ((const char *) pointer - sizeof(uint64)));
248 :
249 : /* Disallow access to the uint64 header */
250 : VALGRIND_MAKE_MEM_NOACCESS((char *) pointer - sizeof(uint64), sizeof(uint64));
251 :
252 0 : return header;
253 : }
254 :
255 : /*
256 : * MemoryContextTraverseNext
257 : * Helper function to traverse all descendants of a memory context
258 : * without recursion.
259 : *
260 : * Recursion could lead to out-of-stack errors with deep context hierarchies,
261 : * which would be unpleasant in error cleanup code paths.
262 : *
263 : * To process 'context' and all its descendants, use a loop like this:
264 : *
265 : * <process 'context'>
266 : * for (MemoryContext curr = context->firstchild;
267 : * curr != NULL;
268 : * curr = MemoryContextTraverseNext(curr, context))
269 : * {
270 : * <process 'curr'>
271 : * }
272 : *
273 : * This visits all the contexts in pre-order, that is a node is visited
274 : * before its children.
275 : */
276 : static MemoryContext
277 2189916 : MemoryContextTraverseNext(MemoryContext curr, MemoryContext top)
278 : {
279 : /* After processing a node, traverse to its first child if any */
280 2189916 : if (curr->firstchild != NULL)
281 0 : return curr->firstchild;
282 :
283 : /*
284 : * After processing a childless node, traverse to its next sibling if
285 : * there is one. If there isn't, traverse back up to the parent (which
286 : * has already been visited, and now so have all its descendants). We're
287 : * done if that is "top", otherwise traverse to its next sibling if any,
288 : * otherwise repeat moving up.
289 : */
290 2189916 : while (curr->nextchild == NULL)
291 : {
292 839642 : curr = curr->parent;
293 839642 : if (curr == top)
294 839642 : return NULL;
295 : }
296 1350274 : return curr->nextchild;
297 : }
298 :
299 : /*
300 : * Support routines to trap use of invalid memory context method IDs
301 : * (from calling pfree or the like on a bogus pointer). As a possible
302 : * aid in debugging, we report the header word along with the pointer
303 : * address (if we got here, there must be an accessible header word).
304 : */
305 : static void
306 0 : BogusFree(void *pointer)
307 : {
308 0 : elog(ERROR, "pfree called with invalid pointer %p (header 0x%016" PRIx64 ")",
309 : pointer, GetMemoryChunkHeader(pointer));
310 : }
311 :
312 : static void *
313 0 : BogusRealloc(void *pointer, Size size, int flags)
314 : {
315 0 : elog(ERROR, "repalloc called with invalid pointer %p (header 0x%016" PRIx64 ")",
316 : pointer, GetMemoryChunkHeader(pointer));
317 : return NULL; /* keep compiler quiet */
318 : }
319 :
320 : static MemoryContext
321 0 : BogusGetChunkContext(void *pointer)
322 : {
323 0 : elog(ERROR, "GetMemoryChunkContext called with invalid pointer %p (header 0x%016" PRIx64 ")",
324 : pointer, GetMemoryChunkHeader(pointer));
325 : return NULL; /* keep compiler quiet */
326 : }
327 :
328 : static Size
329 0 : BogusGetChunkSpace(void *pointer)
330 : {
331 0 : elog(ERROR, "GetMemoryChunkSpace called with invalid pointer %p (header 0x%016" PRIx64 ")",
332 : pointer, GetMemoryChunkHeader(pointer));
333 : return 0; /* keep compiler quiet */
334 : }
335 :
336 :
337 : /*****************************************************************************
338 : * EXPORTED ROUTINES *
339 : *****************************************************************************/
340 :
341 :
342 : /*
343 : * MemoryContextInit
344 : * Start up the memory-context subsystem.
345 : *
346 : * This must be called before creating contexts or allocating memory in
347 : * contexts. TopMemoryContext and ErrorContext are initialized here;
348 : * other contexts must be created afterwards.
349 : *
350 : * In normal multi-backend operation, this is called once during
351 : * postmaster startup, and not at all by individual backend startup
352 : * (since the backends inherit an already-initialized context subsystem
353 : * by virtue of being forked off the postmaster). But in an EXEC_BACKEND
354 : * build, each process must do this for itself.
355 : *
356 : * In a standalone backend this must be called during backend startup.
357 : */
358 : void
359 3972 : MemoryContextInit(void)
360 : {
361 : Assert(TopMemoryContext == NULL);
362 :
363 : /*
364 : * First, initialize TopMemoryContext, which is the parent of all others.
365 : */
366 3972 : TopMemoryContext = AllocSetContextCreate((MemoryContext) NULL,
367 : "TopMemoryContext",
368 : ALLOCSET_DEFAULT_SIZES);
369 :
370 : /*
371 : * Not having any other place to point CurrentMemoryContext, make it point
372 : * to TopMemoryContext. Caller should change this soon!
373 : */
374 3972 : CurrentMemoryContext = TopMemoryContext;
375 :
376 : /*
377 : * Initialize ErrorContext as an AllocSetContext with slow growth rate ---
378 : * we don't really expect much to be allocated in it. More to the point,
379 : * require it to contain at least 8K at all times. This is the only case
380 : * where retained memory in a context is *essential* --- we want to be
381 : * sure ErrorContext still has some memory even if we've run out
382 : * elsewhere! Also, allow allocations in ErrorContext within a critical
383 : * section. Otherwise a PANIC will cause an assertion failure in the error
384 : * reporting code, before printing out the real cause of the failure.
385 : *
386 : * This should be the last step in this function, as elog.c assumes memory
387 : * management works once ErrorContext is non-null.
388 : */
389 3972 : ErrorContext = AllocSetContextCreate(TopMemoryContext,
390 : "ErrorContext",
391 : 8 * 1024,
392 : 8 * 1024,
393 : 8 * 1024);
394 3972 : MemoryContextAllowInCriticalSection(ErrorContext, true);
395 3972 : }
396 :
397 : /*
398 : * MemoryContextReset
399 : * Release all space allocated within a context and delete all its
400 : * descendant contexts (but not the named context itself).
401 : */
402 : void
403 336473602 : MemoryContextReset(MemoryContext context)
404 : {
405 : Assert(MemoryContextIsValid(context));
406 :
407 : /* save a function call in common case where there are no children */
408 336473602 : if (context->firstchild != NULL)
409 713166 : MemoryContextDeleteChildren(context);
410 :
411 : /* save a function call if no pallocs since startup or last reset */
412 336473602 : if (!context->isReset)
413 47804082 : MemoryContextResetOnly(context);
414 336473602 : }
415 :
416 : /*
417 : * MemoryContextResetOnly
418 : * Release all space allocated within a context.
419 : * Nothing is done to the context's descendant contexts.
420 : */
421 : void
422 53935818 : MemoryContextResetOnly(MemoryContext context)
423 : {
424 : Assert(MemoryContextIsValid(context));
425 :
426 : /* Nothing to do if no pallocs since startup or last reset */
427 53935818 : if (!context->isReset)
428 : {
429 53934612 : MemoryContextCallResetCallbacks(context);
430 :
431 : /*
432 : * If context->ident points into the context's memory, it will become
433 : * a dangling pointer. We could prevent that by setting it to NULL
434 : * here, but that would break valid coding patterns that keep the
435 : * ident elsewhere, e.g. in a parent context. So for now we assume
436 : * the programmer got it right.
437 : */
438 :
439 53934612 : context->methods->reset(context);
440 53934612 : context->isReset = true;
441 : }
442 53935818 : }
443 :
444 : /*
445 : * MemoryContextResetChildren
446 : * Release all space allocated within a context's descendants,
447 : * but don't delete the contexts themselves. The named context
448 : * itself is not touched.
449 : */
450 : void
451 0 : MemoryContextResetChildren(MemoryContext context)
452 : {
453 : Assert(MemoryContextIsValid(context));
454 :
455 0 : for (MemoryContext curr = context->firstchild;
456 0 : curr != NULL;
457 0 : curr = MemoryContextTraverseNext(curr, context))
458 : {
459 0 : MemoryContextResetOnly(curr);
460 : }
461 0 : }
462 :
463 : /*
464 : * MemoryContextDelete
465 : * Delete a context and its descendants, and release all space
466 : * allocated therein.
467 : *
468 : * The type-specific delete routine removes all storage for the context,
469 : * but we have to deal with descendant nodes here.
470 : */
471 : void
472 9820182 : MemoryContextDelete(MemoryContext context)
473 : {
474 : MemoryContext curr;
475 :
476 : Assert(MemoryContextIsValid(context));
477 :
478 : /*
479 : * Delete subcontexts from the bottom up.
480 : *
481 : * Note: Do not use recursion here. A "stack depth limit exceeded" error
482 : * would be unpleasant if we're already in the process of cleaning up from
483 : * transaction abort. We also cannot use MemoryContextTraverseNext() here
484 : * because we modify the tree as we go.
485 : */
486 9820182 : curr = context;
487 : for (;;)
488 1679002 : {
489 : MemoryContext parent;
490 :
491 : /* Descend down until we find a leaf context with no children */
492 13178186 : while (curr->firstchild != NULL)
493 1679002 : curr = curr->firstchild;
494 :
495 : /*
496 : * We're now at a leaf with no children. Free it and continue from the
497 : * parent. Or if this was the original node, we're all done.
498 : */
499 11499184 : parent = curr->parent;
500 11499184 : MemoryContextDeleteOnly(curr);
501 :
502 11499184 : if (curr == context)
503 9820182 : break;
504 1679002 : curr = parent;
505 : }
506 9820182 : }
507 :
508 : /*
509 : * Subroutine of MemoryContextDelete,
510 : * to delete a context that has no children.
511 : * We must also delink the context from its parent, if it has one.
512 : */
513 : static void
514 11499184 : MemoryContextDeleteOnly(MemoryContext context)
515 : {
516 : Assert(MemoryContextIsValid(context));
517 : /* We had better not be deleting TopMemoryContext ... */
518 : Assert(context != TopMemoryContext);
519 : /* And not CurrentMemoryContext, either */
520 : Assert(context != CurrentMemoryContext);
521 : /* All the children should've been deleted already */
522 : Assert(context->firstchild == NULL);
523 :
524 : /*
525 : * It's not entirely clear whether 'tis better to do this before or after
526 : * delinking the context; but an error in a callback will likely result in
527 : * leaking the whole context (if it's not a root context) if we do it
528 : * after, so let's do it before.
529 : */
530 11499184 : MemoryContextCallResetCallbacks(context);
531 :
532 : /*
533 : * We delink the context from its parent before deleting it, so that if
534 : * there's an error we won't have deleted/busted contexts still attached
535 : * to the context tree. Better a leak than a crash.
536 : */
537 11499184 : MemoryContextSetParent(context, NULL);
538 :
539 : /*
540 : * Also reset the context's ident pointer, in case it points into the
541 : * context. This would only matter if someone tries to get stats on the
542 : * (already unlinked) context, which is unlikely, but let's be safe.
543 : */
544 11499184 : context->ident = NULL;
545 :
546 11499184 : context->methods->delete_context(context);
547 11499184 : }
548 :
549 : /*
550 : * MemoryContextDeleteChildren
551 : * Delete all the descendants of the named context and release all
552 : * space allocated therein. The named context itself is not touched.
553 : */
554 : void
555 1168844 : MemoryContextDeleteChildren(MemoryContext context)
556 : {
557 : Assert(MemoryContextIsValid(context));
558 :
559 : /*
560 : * MemoryContextDelete will delink the child from me, so just iterate as
561 : * long as there is a child.
562 : */
563 1958390 : while (context->firstchild != NULL)
564 789546 : MemoryContextDelete(context->firstchild);
565 1168844 : }
566 :
567 : /*
568 : * MemoryContextRegisterResetCallback
569 : * Register a function to be called before next context reset/delete.
570 : * Such callbacks will be called in reverse order of registration.
571 : *
572 : * The caller is responsible for allocating a MemoryContextCallback struct
573 : * to hold the info about this callback request, and for filling in the
574 : * "func" and "arg" fields in the struct to show what function to call with
575 : * what argument. Typically the callback struct should be allocated within
576 : * the specified context, since that means it will automatically be freed
577 : * when no longer needed.
578 : *
579 : * Note that callers can assume this cannot fail.
580 : */
581 : void
582 111330 : MemoryContextRegisterResetCallback(MemoryContext context,
583 : MemoryContextCallback *cb)
584 : {
585 : Assert(MemoryContextIsValid(context));
586 :
587 : /* Push onto head so this will be called before older registrants. */
588 111330 : cb->next = context->reset_cbs;
589 111330 : context->reset_cbs = cb;
590 : /* Mark the context as non-reset (it probably is already). */
591 111330 : context->isReset = false;
592 111330 : }
593 :
594 : /*
595 : * MemoryContextUnregisterResetCallback
596 : * Undo the effects of MemoryContextRegisterResetCallback.
597 : *
598 : * This can be used if a callback's effects are no longer required
599 : * at some point before the context has been reset/deleted. It is the
600 : * caller's responsibility to pfree the callback struct (if needed).
601 : *
602 : * An assertion failure occurs if the callback was not registered.
603 : * We could alternatively define that case as a no-op, but that seems too
604 : * likely to mask programming errors such as passing the wrong context.
605 : */
606 : void
607 26664 : MemoryContextUnregisterResetCallback(MemoryContext context,
608 : MemoryContextCallback *cb)
609 : {
610 : MemoryContextCallback *prev,
611 : *cur;
612 :
613 : Assert(MemoryContextIsValid(context));
614 :
615 26694 : for (prev = NULL, cur = context->reset_cbs; cur != NULL;
616 30 : prev = cur, cur = cur->next)
617 : {
618 26694 : if (cur != cb)
619 30 : continue;
620 26664 : if (prev)
621 30 : prev->next = cur->next;
622 : else
623 26634 : context->reset_cbs = cur->next;
624 26664 : return;
625 : }
626 : Assert(false);
627 : }
628 :
629 : /*
630 : * MemoryContextCallResetCallbacks
631 : * Internal function to call all registered callbacks for context.
632 : */
633 : static void
634 65433796 : MemoryContextCallResetCallbacks(MemoryContext context)
635 : {
636 : MemoryContextCallback *cb;
637 :
638 : /*
639 : * We pop each callback from the list before calling. That way, if an
640 : * error occurs inside the callback, we won't try to call it a second time
641 : * in the likely event that we reset or delete the context later.
642 : */
643 65518002 : while ((cb = context->reset_cbs) != NULL)
644 : {
645 84206 : context->reset_cbs = cb->next;
646 84206 : cb->func(cb->arg);
647 : }
648 65433796 : }
649 :
650 : /*
651 : * MemoryContextSetIdentifier
652 : * Set the identifier string for a memory context.
653 : *
654 : * An identifier can be provided to help distinguish among different contexts
655 : * of the same kind in memory context stats dumps. The identifier string
656 : * must live at least as long as the context it is for; typically it is
657 : * allocated inside that context, so that it automatically goes away on
658 : * context deletion. Pass id = NULL to forget any old identifier.
659 : */
660 : void
661 5070670 : MemoryContextSetIdentifier(MemoryContext context, const char *id)
662 : {
663 : Assert(MemoryContextIsValid(context));
664 5070670 : context->ident = id;
665 5070670 : }
666 :
667 : /*
668 : * MemoryContextSetParent
669 : * Change a context to belong to a new parent (or no parent).
670 : *
671 : * We provide this as an API function because it is sometimes useful to
672 : * change a context's lifespan after creation. For example, a context
673 : * might be created underneath a transient context, filled with data,
674 : * and then reparented underneath CacheMemoryContext to make it long-lived.
675 : * In this way no special effort is needed to get rid of the context in case
676 : * a failure occurs before its contents are completely set up.
677 : *
678 : * Callers often assume that this function cannot fail, so don't put any
679 : * elog(ERROR) calls in it.
680 : *
681 : * A possible caller error is to reparent a context under itself, creating
682 : * a loop in the context graph. We assert here that context != new_parent,
683 : * but checking for multi-level loops seems more trouble than it's worth.
684 : */
685 : void
686 11797970 : MemoryContextSetParent(MemoryContext context, MemoryContext new_parent)
687 : {
688 : Assert(MemoryContextIsValid(context));
689 : Assert(context != new_parent);
690 :
691 : /* Fast path if it's got correct parent already */
692 11797970 : if (new_parent == context->parent)
693 9426 : return;
694 :
695 : /* Delink from existing parent, if any */
696 11788544 : if (context->parent)
697 : {
698 11788544 : MemoryContext parent = context->parent;
699 :
700 11788544 : if (context->prevchild != NULL)
701 1166778 : context->prevchild->nextchild = context->nextchild;
702 : else
703 : {
704 : Assert(parent->firstchild == context);
705 10621766 : parent->firstchild = context->nextchild;
706 : }
707 :
708 11788544 : if (context->nextchild != NULL)
709 5104712 : context->nextchild->prevchild = context->prevchild;
710 : }
711 :
712 : /* And relink */
713 11788544 : if (new_parent)
714 : {
715 : Assert(MemoryContextIsValid(new_parent));
716 289360 : context->parent = new_parent;
717 289360 : context->prevchild = NULL;
718 289360 : context->nextchild = new_parent->firstchild;
719 289360 : if (new_parent->firstchild != NULL)
720 263772 : new_parent->firstchild->prevchild = context;
721 289360 : new_parent->firstchild = context;
722 : }
723 : else
724 : {
725 11499184 : context->parent = NULL;
726 11499184 : context->prevchild = NULL;
727 11499184 : context->nextchild = NULL;
728 : }
729 : }
730 :
731 : /*
732 : * MemoryContextAllowInCriticalSection
733 : * Allow/disallow allocations in this memory context within a critical
734 : * section.
735 : *
736 : * Normally, memory allocations are not allowed within a critical section,
737 : * because a failure would lead to PANIC. There are a few exceptions to
738 : * that, like allocations related to debugging code that is not supposed to
739 : * be enabled in production. This function can be used to exempt specific
740 : * memory contexts from the assertion in palloc().
741 : */
742 : void
743 5354 : MemoryContextAllowInCriticalSection(MemoryContext context, bool allow)
744 : {
745 : Assert(MemoryContextIsValid(context));
746 :
747 5354 : context->allowInCritSection = allow;
748 5354 : }
749 :
750 : /*
751 : * GetMemoryChunkContext
752 : * Given a currently-allocated chunk, determine the MemoryContext that
753 : * the chunk belongs to.
754 : */
755 : MemoryContext
756 3854518 : GetMemoryChunkContext(void *pointer)
757 : {
758 3854518 : return MCXT_METHOD(pointer, get_chunk_context) (pointer);
759 : }
760 :
761 : /*
762 : * GetMemoryChunkSpace
763 : * Given a currently-allocated chunk, determine the total space
764 : * it occupies (including all memory-allocation overhead).
765 : *
766 : * This is useful for measuring the total space occupied by a set of
767 : * allocated chunks.
768 : */
769 : Size
770 38094830 : GetMemoryChunkSpace(void *pointer)
771 : {
772 38094830 : return MCXT_METHOD(pointer, get_chunk_space) (pointer);
773 : }
774 :
775 : /*
776 : * MemoryContextGetParent
777 : * Get the parent context (if any) of the specified context
778 : */
779 : MemoryContext
780 17514 : MemoryContextGetParent(MemoryContext context)
781 : {
782 : Assert(MemoryContextIsValid(context));
783 :
784 17514 : return context->parent;
785 : }
786 :
787 : /*
788 : * MemoryContextIsEmpty
789 : * Is a memory context empty of any allocated space?
790 : */
791 : bool
792 10744 : MemoryContextIsEmpty(MemoryContext context)
793 : {
794 : Assert(MemoryContextIsValid(context));
795 :
796 : /*
797 : * For now, we consider a memory context nonempty if it has any children;
798 : * perhaps this should be changed later.
799 : */
800 10744 : if (context->firstchild != NULL)
801 4 : return false;
802 : /* Otherwise use the type-specific inquiry */
803 10740 : return context->methods->is_empty(context);
804 : }
805 :
806 : /*
807 : * Find the memory allocated to blocks for this memory context. If recurse is
808 : * true, also include children.
809 : */
810 : Size
811 1999002 : MemoryContextMemAllocated(MemoryContext context, bool recurse)
812 : {
813 1999002 : Size total = context->mem_allocated;
814 :
815 : Assert(MemoryContextIsValid(context));
816 :
817 1999002 : if (recurse)
818 : {
819 1999002 : for (MemoryContext curr = context->firstchild;
820 4188918 : curr != NULL;
821 2189916 : curr = MemoryContextTraverseNext(curr, context))
822 : {
823 2189916 : total += curr->mem_allocated;
824 : }
825 : }
826 :
827 1999002 : return total;
828 : }
829 :
830 : /*
831 : * Return the memory consumption statistics about the given context and its
832 : * children.
833 : */
834 : void
835 30 : MemoryContextMemConsumed(MemoryContext context,
836 : MemoryContextCounters *consumed)
837 : {
838 : Assert(MemoryContextIsValid(context));
839 :
840 30 : memset(consumed, 0, sizeof(*consumed));
841 :
842 : /* Examine the context itself */
843 30 : context->methods->stats(context, NULL, NULL, consumed, false);
844 :
845 : /* Examine children, using iteration not recursion */
846 30 : for (MemoryContext curr = context->firstchild;
847 30 : curr != NULL;
848 0 : curr = MemoryContextTraverseNext(curr, context))
849 : {
850 0 : curr->methods->stats(curr, NULL, NULL, consumed, false);
851 : }
852 30 : }
853 :
854 : /*
855 : * MemoryContextStats
856 : * Print statistics about the named context and all its descendants.
857 : *
858 : * This is just a debugging utility, so it's not very fancy. However, we do
859 : * make some effort to summarize when the output would otherwise be very long.
860 : * The statistics are sent to stderr.
861 : */
862 : void
863 0 : MemoryContextStats(MemoryContext context)
864 : {
865 : /* Hard-wired limits are usually good enough */
866 0 : MemoryContextStatsDetail(context, 100, 100, true);
867 0 : }
868 :
869 : /*
870 : * MemoryContextStatsDetail
871 : *
872 : * Entry point for use if you want to vary the number of child contexts shown.
873 : *
874 : * If print_to_stderr is true, print statistics about the memory contexts
875 : * with fprintf(stderr), otherwise use ereport().
876 : */
877 : void
878 18 : MemoryContextStatsDetail(MemoryContext context,
879 : int max_level, int max_children,
880 : bool print_to_stderr)
881 : {
882 : MemoryContextCounters grand_totals;
883 :
884 18 : memset(&grand_totals, 0, sizeof(grand_totals));
885 :
886 18 : MemoryContextStatsInternal(context, 1, max_level, max_children,
887 : &grand_totals, print_to_stderr);
888 :
889 18 : if (print_to_stderr)
890 0 : fprintf(stderr,
891 : "Grand total: %zu bytes in %zu blocks; %zu free (%zu chunks); %zu used\n",
892 : grand_totals.totalspace, grand_totals.nblocks,
893 : grand_totals.freespace, grand_totals.freechunks,
894 0 : grand_totals.totalspace - grand_totals.freespace);
895 : else
896 : {
897 : /*
898 : * Use LOG_SERVER_ONLY to prevent the memory contexts from being sent
899 : * to the connected client.
900 : *
901 : * We don't buffer the information about all memory contexts in a
902 : * backend into StringInfo and log it as one message. That would
903 : * require the buffer to be enlarged, risking an OOM as there could be
904 : * a large number of memory contexts in a backend. Instead, we log
905 : * one message per memory context.
906 : */
907 18 : ereport(LOG_SERVER_ONLY,
908 : (errhidestmt(true),
909 : errhidecontext(true),
910 : errmsg_internal("Grand total: %zu bytes in %zu blocks; %zu free (%zu chunks); %zu used",
911 : grand_totals.totalspace, grand_totals.nblocks,
912 : grand_totals.freespace, grand_totals.freechunks,
913 : grand_totals.totalspace - grand_totals.freespace)));
914 : }
915 18 : }
916 :
917 : /*
918 : * MemoryContextStatsInternal
919 : * One recursion level for MemoryContextStats
920 : *
921 : * Print stats for this context if possible, but in any case accumulate counts
922 : * into *totals (if not NULL).
923 : */
924 : static void
925 1626 : MemoryContextStatsInternal(MemoryContext context, int level,
926 : int max_level, int max_children,
927 : MemoryContextCounters *totals,
928 : bool print_to_stderr)
929 : {
930 : MemoryContext child;
931 : int ichild;
932 :
933 : Assert(MemoryContextIsValid(context));
934 :
935 : /* Examine the context itself */
936 1626 : context->methods->stats(context,
937 : MemoryContextStatsPrint,
938 : &level,
939 : totals, print_to_stderr);
940 :
941 : /*
942 : * Examine children.
943 : *
944 : * If we are past the recursion depth limit or already running low on
945 : * stack, do not print them explicitly but just summarize them. Similarly,
946 : * if there are more than max_children of them, we do not print the rest
947 : * explicitly, but just summarize them.
948 : */
949 1626 : child = context->firstchild;
950 1626 : ichild = 0;
951 1626 : if (level <= max_level && !stack_is_too_deep())
952 : {
953 3234 : for (; child != NULL && ichild < max_children;
954 1608 : child = child->nextchild, ichild++)
955 : {
956 1608 : MemoryContextStatsInternal(child, level + 1,
957 : max_level, max_children,
958 : totals,
959 : print_to_stderr);
960 : }
961 : }
962 :
963 1626 : if (child != NULL)
964 : {
965 : /* Summarize the rest of the children, avoiding recursion. */
966 : MemoryContextCounters local_totals;
967 :
968 0 : memset(&local_totals, 0, sizeof(local_totals));
969 :
970 0 : ichild = 0;
971 0 : while (child != NULL)
972 : {
973 0 : child->methods->stats(child, NULL, NULL, &local_totals, false);
974 0 : ichild++;
975 0 : child = MemoryContextTraverseNext(child, context);
976 : }
977 :
978 0 : if (print_to_stderr)
979 : {
980 0 : for (int i = 0; i < level; i++)
981 0 : fprintf(stderr, " ");
982 0 : fprintf(stderr,
983 : "%d more child contexts containing %zu total in %zu blocks; %zu free (%zu chunks); %zu used\n",
984 : ichild,
985 : local_totals.totalspace,
986 : local_totals.nblocks,
987 : local_totals.freespace,
988 : local_totals.freechunks,
989 0 : local_totals.totalspace - local_totals.freespace);
990 : }
991 : else
992 0 : ereport(LOG_SERVER_ONLY,
993 : (errhidestmt(true),
994 : errhidecontext(true),
995 : errmsg_internal("level: %d; %d more child contexts containing %zu total in %zu blocks; %zu free (%zu chunks); %zu used",
996 : level,
997 : ichild,
998 : local_totals.totalspace,
999 : local_totals.nblocks,
1000 : local_totals.freespace,
1001 : local_totals.freechunks,
1002 : local_totals.totalspace - local_totals.freespace)));
1003 :
1004 0 : if (totals)
1005 : {
1006 0 : totals->nblocks += local_totals.nblocks;
1007 0 : totals->freechunks += local_totals.freechunks;
1008 0 : totals->totalspace += local_totals.totalspace;
1009 0 : totals->freespace += local_totals.freespace;
1010 : }
1011 : }
1012 1626 : }
1013 :
1014 : /*
1015 : * MemoryContextStatsPrint
1016 : * Print callback used by MemoryContextStatsInternal
1017 : *
1018 : * For now, the passthru pointer just points to "int level"; later we might
1019 : * make that more complicated.
1020 : */
1021 : static void
1022 1626 : MemoryContextStatsPrint(MemoryContext context, void *passthru,
1023 : const char *stats_string,
1024 : bool print_to_stderr)
1025 : {
1026 1626 : int level = *(int *) passthru;
1027 1626 : const char *name = context->name;
1028 1626 : const char *ident = context->ident;
1029 : char truncated_ident[110];
1030 : int i;
1031 :
1032 : /*
1033 : * It seems preferable to label dynahash contexts with just the hash table
1034 : * name. Those are already unique enough, so the "dynahash" part isn't
1035 : * very helpful, and this way is more consistent with pre-v11 practice.
1036 : */
1037 1626 : if (ident && strcmp(name, "dynahash") == 0)
1038 : {
1039 216 : name = ident;
1040 216 : ident = NULL;
1041 : }
1042 :
1043 1626 : truncated_ident[0] = '\0';
1044 :
1045 1626 : if (ident)
1046 : {
1047 : /*
1048 : * Some contexts may have very long identifiers (e.g., SQL queries).
1049 : * Arbitrarily truncate at 100 bytes, but be careful not to break
1050 : * multibyte characters. Also, replace ASCII control characters, such
1051 : * as newlines, with spaces.
1052 : */
1053 1140 : int idlen = strlen(ident);
1054 1140 : bool truncated = false;
1055 :
1056 1140 : strcpy(truncated_ident, ": ");
1057 1140 : i = strlen(truncated_ident);
1058 :
1059 1140 : if (idlen > 100)
1060 : {
1061 0 : idlen = pg_mbcliplen(ident, idlen, 100);
1062 0 : truncated = true;
1063 : }
1064 :
1065 31866 : while (idlen-- > 0)
1066 : {
1067 30726 : unsigned char c = *ident++;
1068 :
1069 30726 : if (c < ' ')
1070 0 : c = ' ';
1071 30726 : truncated_ident[i++] = c;
1072 : }
1073 1140 : truncated_ident[i] = '\0';
1074 :
1075 1140 : if (truncated)
1076 0 : strcat(truncated_ident, "...");
1077 : }
1078 :
1079 1626 : if (print_to_stderr)
1080 : {
1081 0 : for (i = 1; i < level; i++)
1082 0 : fprintf(stderr, " ");
1083 0 : fprintf(stderr, "%s: %s%s\n", name, stats_string, truncated_ident);
1084 : }
1085 : else
1086 1626 : ereport(LOG_SERVER_ONLY,
1087 : (errhidestmt(true),
1088 : errhidecontext(true),
1089 : errmsg_internal("level: %d; %s: %s%s",
1090 : level, name, stats_string, truncated_ident)));
1091 1626 : }
1092 :
1093 : /*
1094 : * MemoryContextCheck
1095 : * Check all chunks in the named context and its children.
1096 : *
1097 : * This is just a debugging utility, so it's not fancy.
1098 : */
1099 : #ifdef MEMORY_CONTEXT_CHECKING
1100 : void
1101 : MemoryContextCheck(MemoryContext context)
1102 : {
1103 : Assert(MemoryContextIsValid(context));
1104 : context->methods->check(context);
1105 :
1106 : for (MemoryContext curr = context->firstchild;
1107 : curr != NULL;
1108 : curr = MemoryContextTraverseNext(curr, context))
1109 : {
1110 : Assert(MemoryContextIsValid(curr));
1111 : curr->methods->check(curr);
1112 : }
1113 : }
1114 : #endif
1115 :
1116 : /*
1117 : * MemoryContextCreate
1118 : * Context-type-independent part of context creation.
1119 : *
1120 : * This is only intended to be called by context-type-specific
1121 : * context creation routines, not by the unwashed masses.
1122 : *
1123 : * The memory context creation procedure goes like this:
1124 : * 1. Context-type-specific routine makes some initial space allocation,
1125 : * including enough space for the context header. If it fails,
1126 : * it can ereport() with no damage done.
1127 : * 2. Context-type-specific routine sets up all type-specific fields of
1128 : * the header (those beyond MemoryContextData proper), as well as any
1129 : * other management fields it needs to have a fully valid context.
1130 : * Usually, failure in this step is impossible, but if it's possible
1131 : * the initial space allocation should be freed before ereport'ing.
1132 : * 3. Context-type-specific routine calls MemoryContextCreate() to fill in
1133 : * the generic header fields and link the context into the context tree.
1134 : * 4. We return to the context-type-specific routine, which finishes
1135 : * up type-specific initialization. This routine can now do things
1136 : * that might fail (like allocate more memory), so long as it's
1137 : * sure the node is left in a state that delete will handle.
1138 : *
1139 : * node: the as-yet-uninitialized common part of the context header node.
1140 : * tag: NodeTag code identifying the memory context type.
1141 : * method_id: MemoryContextMethodID of the context-type being created.
1142 : * parent: parent context, or NULL if this will be a top-level context.
1143 : * name: name of context (must be statically allocated).
1144 : *
1145 : * Context routines generally assume that MemoryContextCreate can't fail,
1146 : * so this can contain Assert but not elog/ereport.
1147 : */
1148 : void
1149 15268472 : MemoryContextCreate(MemoryContext node,
1150 : NodeTag tag,
1151 : MemoryContextMethodID method_id,
1152 : MemoryContext parent,
1153 : const char *name)
1154 : {
1155 : /* Creating new memory contexts is not allowed in a critical section */
1156 : Assert(CritSectionCount == 0);
1157 :
1158 : /* Validate parent, to help prevent crazy context linkages */
1159 : Assert(parent == NULL || MemoryContextIsValid(parent));
1160 : Assert(node != parent);
1161 :
1162 : /* Initialize all standard fields of memory context header */
1163 15268472 : node->type = tag;
1164 15268472 : node->isReset = true;
1165 15268472 : node->methods = &mcxt_methods[method_id];
1166 15268472 : node->parent = parent;
1167 15268472 : node->firstchild = NULL;
1168 15268472 : node->mem_allocated = 0;
1169 15268472 : node->prevchild = NULL;
1170 15268472 : node->name = name;
1171 15268472 : node->ident = NULL;
1172 15268472 : node->reset_cbs = NULL;
1173 :
1174 : /* OK to link node into context tree */
1175 15268472 : if (parent)
1176 : {
1177 15264398 : node->nextchild = parent->firstchild;
1178 15264398 : if (parent->firstchild != NULL)
1179 8710420 : parent->firstchild->prevchild = node;
1180 15264398 : parent->firstchild = node;
1181 : /* inherit allowInCritSection flag from parent */
1182 15264398 : node->allowInCritSection = parent->allowInCritSection;
1183 : }
1184 : else
1185 : {
1186 4074 : node->nextchild = NULL;
1187 4074 : node->allowInCritSection = false;
1188 : }
1189 15268472 : }
1190 :
1191 : /*
1192 : * MemoryContextAllocationFailure
1193 : * For use by MemoryContextMethods implementations to handle when malloc
1194 : * returns NULL. The behavior is specific to whether MCXT_ALLOC_NO_OOM
1195 : * is in 'flags'.
1196 : */
1197 : void *
1198 0 : MemoryContextAllocationFailure(MemoryContext context, Size size, int flags)
1199 : {
1200 0 : if ((flags & MCXT_ALLOC_NO_OOM) == 0)
1201 : {
1202 0 : if (TopMemoryContext)
1203 0 : MemoryContextStats(TopMemoryContext);
1204 0 : ereport(ERROR,
1205 : (errcode(ERRCODE_OUT_OF_MEMORY),
1206 : errmsg("out of memory"),
1207 : errdetail("Failed on request of size %zu in memory context \"%s\".",
1208 : size, context->name)));
1209 : }
1210 0 : return NULL;
1211 : }
1212 :
1213 : /*
1214 : * MemoryContextSizeFailure
1215 : * For use by MemoryContextMethods implementations to handle invalid
1216 : * memory allocation request sizes.
1217 : */
1218 : void
1219 0 : MemoryContextSizeFailure(MemoryContext context, Size size, int flags)
1220 : {
1221 0 : elog(ERROR, "invalid memory alloc request size %zu", size);
1222 : }
1223 :
1224 : /*
1225 : * MemoryContextAlloc
1226 : * Allocate space within the specified context.
1227 : *
1228 : * This could be turned into a macro, but we'd have to import
1229 : * nodes/memnodes.h into postgres.h which seems a bad idea.
1230 : */
1231 : void *
1232 190132270 : MemoryContextAlloc(MemoryContext context, Size size)
1233 : {
1234 : void *ret;
1235 :
1236 : Assert(MemoryContextIsValid(context));
1237 : AssertNotInCriticalSection(context);
1238 :
1239 190132270 : context->isReset = false;
1240 :
1241 : /*
1242 : * For efficiency reasons, we purposefully offload the handling of
1243 : * allocation failures to the MemoryContextMethods implementation as this
1244 : * allows these checks to be performed only when an actual malloc needs to
1245 : * be done to request more memory from the OS. Additionally, not having
1246 : * to execute any instructions after this call allows the compiler to use
1247 : * the sibling call optimization. If you're considering adding code after
1248 : * this call, consider making it the responsibility of the 'alloc'
1249 : * function instead.
1250 : */
1251 190132270 : ret = context->methods->alloc(context, size, 0);
1252 :
1253 : VALGRIND_MEMPOOL_ALLOC(context, ret, size);
1254 :
1255 190132270 : return ret;
1256 : }
1257 :
1258 : /*
1259 : * MemoryContextAllocZero
1260 : * Like MemoryContextAlloc, but clears allocated memory
1261 : *
1262 : * We could just call MemoryContextAlloc then clear the memory, but this
1263 : * is a very common combination, so we provide the combined operation.
1264 : */
1265 : void *
1266 45135756 : MemoryContextAllocZero(MemoryContext context, Size size)
1267 : {
1268 : void *ret;
1269 :
1270 : Assert(MemoryContextIsValid(context));
1271 : AssertNotInCriticalSection(context);
1272 :
1273 45135756 : context->isReset = false;
1274 :
1275 45135756 : ret = context->methods->alloc(context, size, 0);
1276 :
1277 : VALGRIND_MEMPOOL_ALLOC(context, ret, size);
1278 :
1279 566204076 : MemSetAligned(ret, 0, size);
1280 :
1281 45135756 : return ret;
1282 : }
1283 :
1284 : /*
1285 : * MemoryContextAllocExtended
1286 : * Allocate space within the specified context using the given flags.
1287 : */
1288 : void *
1289 8508408 : MemoryContextAllocExtended(MemoryContext context, Size size, int flags)
1290 : {
1291 : void *ret;
1292 :
1293 : Assert(MemoryContextIsValid(context));
1294 : AssertNotInCriticalSection(context);
1295 :
1296 8508408 : if (!((flags & MCXT_ALLOC_HUGE) != 0 ? AllocHugeSizeIsValid(size) :
1297 : AllocSizeIsValid(size)))
1298 0 : elog(ERROR, "invalid memory alloc request size %zu", size);
1299 :
1300 8508408 : context->isReset = false;
1301 :
1302 8508408 : ret = context->methods->alloc(context, size, flags);
1303 8508408 : if (unlikely(ret == NULL))
1304 0 : return NULL;
1305 :
1306 : VALGRIND_MEMPOOL_ALLOC(context, ret, size);
1307 :
1308 8508408 : if ((flags & MCXT_ALLOC_ZERO) != 0)
1309 313378 : MemSetAligned(ret, 0, size);
1310 :
1311 8508408 : return ret;
1312 : }
1313 :
1314 : /*
1315 : * HandleLogMemoryContextInterrupt
1316 : * Handle receipt of an interrupt indicating logging of memory
1317 : * contexts.
1318 : *
1319 : * All the actual work is deferred to ProcessLogMemoryContextInterrupt(),
1320 : * because we cannot safely emit a log message inside the signal handler.
1321 : */
1322 : void
1323 18 : HandleLogMemoryContextInterrupt(void)
1324 : {
1325 18 : InterruptPending = true;
1326 18 : LogMemoryContextPending = true;
1327 : /* latch will be set by procsignal_sigusr1_handler */
1328 18 : }
1329 :
1330 : /*
1331 : * ProcessLogMemoryContextInterrupt
1332 : * Perform logging of memory contexts of this backend process.
1333 : *
1334 : * Any backend that participates in ProcSignal signaling must arrange
1335 : * to call this function if we see LogMemoryContextPending set.
1336 : * It is called from CHECK_FOR_INTERRUPTS(), which is enough because
1337 : * the target process for logging of memory contexts is a backend.
1338 : */
1339 : void
1340 18 : ProcessLogMemoryContextInterrupt(void)
1341 : {
1342 18 : LogMemoryContextPending = false;
1343 :
1344 : /*
1345 : * Exit immediately if memory context logging is already in progress. This
1346 : * prevents recursive calls, which could occur if logging is requested
1347 : * repeatedly and rapidly, potentially leading to infinite recursion and a
1348 : * crash.
1349 : */
1350 18 : if (LogMemoryContextInProgress)
1351 0 : return;
1352 18 : LogMemoryContextInProgress = true;
1353 :
1354 18 : PG_TRY();
1355 : {
1356 : /*
1357 : * Use LOG_SERVER_ONLY to prevent this message from being sent to the
1358 : * connected client.
1359 : */
1360 18 : ereport(LOG_SERVER_ONLY,
1361 : (errhidestmt(true),
1362 : errhidecontext(true),
1363 : errmsg("logging memory contexts of PID %d", MyProcPid)));
1364 :
1365 : /*
1366 : * When a backend process is consuming huge memory, logging all its
1367 : * memory contexts might overrun available disk space. To prevent
1368 : * this, we limit the depth of the hierarchy, as well as the number of
1369 : * child contexts to log per parent to 100.
1370 : *
1371 : * As with MemoryContextStats(), we suppose that practical cases where
1372 : * the dump gets long will typically be huge numbers of siblings under
1373 : * the same parent context; while the additional debugging value from
1374 : * seeing details about individual siblings beyond 100 will not be
1375 : * large.
1376 : */
1377 18 : MemoryContextStatsDetail(TopMemoryContext, 100, 100, false);
1378 : }
1379 0 : PG_FINALLY();
1380 : {
1381 18 : LogMemoryContextInProgress = false;
1382 : }
1383 18 : PG_END_TRY();
1384 : }
1385 :
1386 : void *
1387 689870276 : palloc(Size size)
1388 : {
1389 : /* duplicates MemoryContextAlloc to avoid increased overhead */
1390 : void *ret;
1391 689870276 : MemoryContext context = CurrentMemoryContext;
1392 :
1393 : Assert(MemoryContextIsValid(context));
1394 : AssertNotInCriticalSection(context);
1395 :
1396 689870276 : context->isReset = false;
1397 :
1398 : /*
1399 : * For efficiency reasons, we purposefully offload the handling of
1400 : * allocation failures to the MemoryContextMethods implementation as this
1401 : * allows these checks to be performed only when an actual malloc needs to
1402 : * be done to request more memory from the OS. Additionally, not having
1403 : * to execute any instructions after this call allows the compiler to use
1404 : * the sibling call optimization. If you're considering adding code after
1405 : * this call, consider making it the responsibility of the 'alloc'
1406 : * function instead.
1407 : */
1408 689870276 : ret = context->methods->alloc(context, size, 0);
1409 : /* We expect OOM to be handled by the alloc function */
1410 : Assert(ret != NULL);
1411 : VALGRIND_MEMPOOL_ALLOC(context, ret, size);
1412 :
1413 689870276 : return ret;
1414 : }
1415 :
1416 : void *
1417 491903114 : palloc0(Size size)
1418 : {
1419 : /* duplicates MemoryContextAllocZero to avoid increased overhead */
1420 : void *ret;
1421 491903114 : MemoryContext context = CurrentMemoryContext;
1422 :
1423 : Assert(MemoryContextIsValid(context));
1424 : AssertNotInCriticalSection(context);
1425 :
1426 491903114 : context->isReset = false;
1427 :
1428 491903114 : ret = context->methods->alloc(context, size, 0);
1429 : /* We expect OOM to be handled by the alloc function */
1430 : Assert(ret != NULL);
1431 : VALGRIND_MEMPOOL_ALLOC(context, ret, size);
1432 :
1433 4460417518 : MemSetAligned(ret, 0, size);
1434 :
1435 491903114 : return ret;
1436 : }
1437 :
1438 : void *
1439 23717472 : palloc_extended(Size size, int flags)
1440 : {
1441 : /* duplicates MemoryContextAllocExtended to avoid increased overhead */
1442 : void *ret;
1443 23717472 : MemoryContext context = CurrentMemoryContext;
1444 :
1445 : Assert(MemoryContextIsValid(context));
1446 : AssertNotInCriticalSection(context);
1447 :
1448 23717472 : context->isReset = false;
1449 :
1450 23717472 : ret = context->methods->alloc(context, size, flags);
1451 23717472 : if (unlikely(ret == NULL))
1452 : {
1453 : /* NULL can be returned only when using MCXT_ALLOC_NO_OOM */
1454 : Assert(flags & MCXT_ALLOC_NO_OOM);
1455 0 : return NULL;
1456 : }
1457 :
1458 : VALGRIND_MEMPOOL_ALLOC(context, ret, size);
1459 :
1460 23717472 : if ((flags & MCXT_ALLOC_ZERO) != 0)
1461 5678 : MemSetAligned(ret, 0, size);
1462 :
1463 23717472 : return ret;
1464 : }
1465 :
1466 : /*
1467 : * MemoryContextAllocAligned
1468 : * Allocate 'size' bytes of memory in 'context' aligned to 'alignto'
1469 : * bytes.
1470 : *
1471 : * Currently, we align addresses by requesting additional bytes from the
1472 : * MemoryContext's standard allocator function and then aligning the returned
1473 : * address by the required alignment. This means that the given MemoryContext
1474 : * must support providing us with a chunk of memory that's larger than 'size'.
1475 : * For allocators such as Slab, that's not going to work, as slab only allows
1476 : * chunks of the size that's specified when the context is created.
1477 : *
1478 : * 'alignto' must be a power of 2.
1479 : * 'flags' may be 0 or set the same as MemoryContextAllocExtended().
1480 : */
1481 : void *
1482 3438822 : MemoryContextAllocAligned(MemoryContext context,
1483 : Size size, Size alignto, int flags)
1484 : {
1485 : MemoryChunk *alignedchunk;
1486 : Size alloc_size;
1487 : void *unaligned;
1488 : void *aligned;
1489 :
1490 : /*
1491 : * Restrict alignto to ensure that it can fit into the "value" field of
1492 : * the redirection MemoryChunk, and that the distance back to the start of
1493 : * the unaligned chunk will fit into the space available for that. This
1494 : * isn't a limitation in practice, since it wouldn't make much sense to
1495 : * waste that much space.
1496 : */
1497 : Assert(alignto < (128 * 1024 * 1024));
1498 :
1499 : /* ensure alignto is a power of 2 */
1500 : Assert((alignto & (alignto - 1)) == 0);
1501 :
1502 : /*
1503 : * If the alignment requirements are less than what we already guarantee
1504 : * then just use the standard allocation function.
1505 : */
1506 3438822 : if (unlikely(alignto <= MAXIMUM_ALIGNOF))
1507 0 : return MemoryContextAllocExtended(context, size, flags);
1508 :
1509 : /*
1510 : * We implement aligned pointers by simply allocating enough memory for
1511 : * the requested size plus the alignment and an additional "redirection"
1512 : * MemoryChunk. This additional MemoryChunk is required for operations
1513 : * such as pfree when used on the pointer returned by this function. We
1514 : * use this redirection MemoryChunk in order to find the pointer to the
1515 : * memory that was returned by the MemoryContextAllocExtended call below.
1516 : * We do that by "borrowing" the block offset field and instead of using
1517 : * that to find the offset into the owning block, we use it to find the
1518 : * original allocated address.
1519 : *
1520 : * Here we must allocate enough extra memory so that we can still align
1521 : * the pointer returned by MemoryContextAllocExtended and also have enough
1522 : * space for the redirection MemoryChunk. Since allocations will already
1523 : * be at least aligned by MAXIMUM_ALIGNOF, we can subtract that amount
1524 : * from the allocation size to save a little memory.
1525 : */
1526 3438822 : alloc_size = size + PallocAlignedExtraBytes(alignto);
1527 :
1528 : #ifdef MEMORY_CONTEXT_CHECKING
1529 : /* ensure there's space for a sentinel byte */
1530 : alloc_size += 1;
1531 : #endif
1532 :
1533 : /*
1534 : * Perform the actual allocation, but do not pass down MCXT_ALLOC_ZERO.
1535 : * This ensures that wasted bytes beyond the aligned chunk do not become
1536 : * DEFINED.
1537 : */
1538 3438822 : unaligned = MemoryContextAllocExtended(context, alloc_size,
1539 : flags & ~MCXT_ALLOC_ZERO);
1540 :
1541 : /* compute the aligned pointer */
1542 3438822 : aligned = (void *) TYPEALIGN(alignto, (char *) unaligned +
1543 : sizeof(MemoryChunk));
1544 :
1545 3438822 : alignedchunk = PointerGetMemoryChunk(aligned);
1546 :
1547 : /*
1548 : * We set the redirect MemoryChunk so that the block offset calculation is
1549 : * used to point back to the 'unaligned' allocated chunk. This allows us
1550 : * to use MemoryChunkGetBlock() to find the unaligned chunk when we need
1551 : * to perform operations such as pfree() and repalloc().
1552 : *
1553 : * We store 'alignto' in the MemoryChunk's 'value' so that we know what
1554 : * the alignment was set to should we ever be asked to realloc this
1555 : * pointer.
1556 : */
1557 3438822 : MemoryChunkSetHdrMask(alignedchunk, unaligned, alignto,
1558 : MCTX_ALIGNED_REDIRECT_ID);
1559 :
1560 : /* double check we produced a correctly aligned pointer */
1561 : Assert((void *) TYPEALIGN(alignto, aligned) == aligned);
1562 :
1563 : #ifdef MEMORY_CONTEXT_CHECKING
1564 : alignedchunk->requested_size = size;
1565 : /* set mark to catch clobber of "unused" space */
1566 : set_sentinel(aligned, size);
1567 : #endif
1568 :
1569 : /*
1570 : * MemoryContextAllocExtended marked the whole unaligned chunk as a
1571 : * vchunk. Undo that, instead making just the aligned chunk be a vchunk.
1572 : * This prevents Valgrind from complaining that the vchunk is possibly
1573 : * leaked, since only pointers to the aligned chunk will exist.
1574 : *
1575 : * After these calls, the aligned chunk will be marked UNDEFINED, and all
1576 : * the rest of the unaligned chunk (the redirection chunk header, the
1577 : * padding bytes before it, and any wasted trailing bytes) will be marked
1578 : * NOACCESS, which is what we want.
1579 : */
1580 : VALGRIND_MEMPOOL_FREE(context, unaligned);
1581 : VALGRIND_MEMPOOL_ALLOC(context, aligned, size);
1582 :
1583 : /* Now zero (and make DEFINED) just the aligned chunk, if requested */
1584 3438822 : if ((flags & MCXT_ALLOC_ZERO) != 0)
1585 176677770 : MemSetAligned(aligned, 0, size);
1586 :
1587 3438822 : return aligned;
1588 : }
1589 :
1590 : /*
1591 : * palloc_aligned
1592 : * Allocate 'size' bytes returning a pointer that's aligned to the
1593 : * 'alignto' boundary.
1594 : *
1595 : * Currently, we align addresses by requesting additional bytes from the
1596 : * MemoryContext's standard allocator function and then aligning the returned
1597 : * address by the required alignment. This means that the given MemoryContext
1598 : * must support providing us with a chunk of memory that's larger than 'size'.
1599 : * For allocators such as Slab, that's not going to work, as slab only allows
1600 : * chunks of the size that's specified when the context is created.
1601 : *
1602 : * 'alignto' must be a power of 2.
1603 : * 'flags' may be 0 or set the same as MemoryContextAllocExtended().
1604 : */
1605 : void *
1606 3310704 : palloc_aligned(Size size, Size alignto, int flags)
1607 : {
1608 3310704 : return MemoryContextAllocAligned(CurrentMemoryContext, size, alignto, flags);
1609 : }
1610 :
1611 : /*
1612 : * pfree
1613 : * Release an allocated chunk.
1614 : */
1615 : void
1616 521135174 : pfree(void *pointer)
1617 : {
1618 : #ifdef USE_VALGRIND
1619 : MemoryContext context = GetMemoryChunkContext(pointer);
1620 : #endif
1621 :
1622 521135174 : MCXT_METHOD(pointer, free_p) (pointer);
1623 :
1624 : VALGRIND_MEMPOOL_FREE(context, pointer);
1625 521135174 : }
1626 :
1627 : /*
1628 : * repalloc
1629 : * Adjust the size of a previously allocated chunk.
1630 : */
1631 : void *
1632 9296008 : repalloc(void *pointer, Size size)
1633 : {
1634 : #if defined(USE_ASSERT_CHECKING) || defined(USE_VALGRIND)
1635 : MemoryContext context = GetMemoryChunkContext(pointer);
1636 : #endif
1637 : void *ret;
1638 :
1639 : AssertNotInCriticalSection(context);
1640 :
1641 : /* isReset must be false already */
1642 : Assert(!context->isReset);
1643 :
1644 : /*
1645 : * For efficiency reasons, we purposefully offload the handling of
1646 : * allocation failures to the MemoryContextMethods implementation as this
1647 : * allows these checks to be performed only when an actual malloc needs to
1648 : * be done to request more memory from the OS. Additionally, not having
1649 : * to execute any instructions after this call allows the compiler to use
1650 : * the sibling call optimization. If you're considering adding code after
1651 : * this call, consider making it the responsibility of the 'realloc'
1652 : * function instead.
1653 : */
1654 9296008 : ret = MCXT_METHOD(pointer, realloc) (pointer, size, 0);
1655 :
1656 : VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size);
1657 :
1658 9296008 : return ret;
1659 : }
1660 :
1661 : /*
1662 : * repalloc_extended
1663 : * Adjust the size of a previously allocated chunk,
1664 : * with HUGE and NO_OOM options.
1665 : */
1666 : void *
1667 98798 : repalloc_extended(void *pointer, Size size, int flags)
1668 : {
1669 : #if defined(USE_ASSERT_CHECKING) || defined(USE_VALGRIND)
1670 : MemoryContext context = GetMemoryChunkContext(pointer);
1671 : #endif
1672 : void *ret;
1673 :
1674 : AssertNotInCriticalSection(context);
1675 :
1676 : /* isReset must be false already */
1677 : Assert(!context->isReset);
1678 :
1679 : /*
1680 : * For efficiency reasons, we purposefully offload the handling of
1681 : * allocation failures to the MemoryContextMethods implementation as this
1682 : * allows these checks to be performed only when an actual malloc needs to
1683 : * be done to request more memory from the OS. Additionally, not having
1684 : * to execute any instructions after this call allows the compiler to use
1685 : * the sibling call optimization. If you're considering adding code after
1686 : * this call, consider making it the responsibility of the 'realloc'
1687 : * function instead.
1688 : */
1689 98798 : ret = MCXT_METHOD(pointer, realloc) (pointer, size, flags);
1690 98798 : if (unlikely(ret == NULL))
1691 0 : return NULL;
1692 :
1693 : VALGRIND_MEMPOOL_CHANGE(context, pointer, ret, size);
1694 :
1695 98798 : return ret;
1696 : }
1697 :
1698 : /*
1699 : * repalloc0
1700 : * Adjust the size of a previously allocated chunk and zero out the added
1701 : * space.
1702 : */
1703 : void *
1704 52524 : repalloc0(void *pointer, Size oldsize, Size size)
1705 : {
1706 : void *ret;
1707 :
1708 : /* catch wrong argument order */
1709 52524 : if (unlikely(oldsize > size))
1710 0 : elog(ERROR, "invalid repalloc0 call: oldsize %zu, new size %zu",
1711 : oldsize, size);
1712 :
1713 52524 : ret = repalloc(pointer, size);
1714 52524 : memset((char *) ret + oldsize, 0, (size - oldsize));
1715 52524 : return ret;
1716 : }
1717 :
1718 : /*
1719 : * MemoryContextAllocHuge
1720 : * Allocate (possibly-expansive) space within the specified context.
1721 : *
1722 : * See considerations in comment at MaxAllocHugeSize.
1723 : */
1724 : void *
1725 3274 : MemoryContextAllocHuge(MemoryContext context, Size size)
1726 : {
1727 : void *ret;
1728 :
1729 : Assert(MemoryContextIsValid(context));
1730 : AssertNotInCriticalSection(context);
1731 :
1732 3274 : context->isReset = false;
1733 :
1734 : /*
1735 : * For efficiency reasons, we purposefully offload the handling of
1736 : * allocation failures to the MemoryContextMethods implementation as this
1737 : * allows these checks to be performed only when an actual malloc needs to
1738 : * be done to request more memory from the OS. Additionally, not having
1739 : * to execute any instructions after this call allows the compiler to use
1740 : * the sibling call optimization. If you're considering adding code after
1741 : * this call, consider making it the responsibility of the 'alloc'
1742 : * function instead.
1743 : */
1744 3274 : ret = context->methods->alloc(context, size, MCXT_ALLOC_HUGE);
1745 :
1746 : VALGRIND_MEMPOOL_ALLOC(context, ret, size);
1747 :
1748 3274 : return ret;
1749 : }
1750 :
1751 : /*
1752 : * repalloc_huge
1753 : * Adjust the size of a previously allocated chunk, permitting a large
1754 : * value. The previous allocation need not have been "huge".
1755 : */
1756 : void *
1757 97906 : repalloc_huge(void *pointer, Size size)
1758 : {
1759 : /* this one seems not worth its own implementation */
1760 97906 : return repalloc_extended(pointer, size, MCXT_ALLOC_HUGE);
1761 : }
1762 :
1763 : /*
1764 : * MemoryContextStrdup
1765 : * Like strdup(), but allocate from the specified context
1766 : */
1767 : char *
1768 94603354 : MemoryContextStrdup(MemoryContext context, const char *string)
1769 : {
1770 : char *nstr;
1771 94603354 : Size len = strlen(string) + 1;
1772 :
1773 94603354 : nstr = (char *) MemoryContextAlloc(context, len);
1774 :
1775 94603354 : memcpy(nstr, string, len);
1776 :
1777 94603354 : return nstr;
1778 : }
1779 :
1780 : char *
1781 90748916 : pstrdup(const char *in)
1782 : {
1783 90748916 : return MemoryContextStrdup(CurrentMemoryContext, in);
1784 : }
1785 :
1786 : /*
1787 : * pnstrdup
1788 : * Like pstrdup(), but append null byte to a
1789 : * not-necessarily-null-terminated input string.
1790 : */
1791 : char *
1792 1658308 : pnstrdup(const char *in, Size len)
1793 : {
1794 : char *out;
1795 :
1796 1658308 : len = strnlen(in, len);
1797 :
1798 1658308 : out = palloc(len + 1);
1799 1658308 : memcpy(out, in, len);
1800 1658308 : out[len] = '\0';
1801 :
1802 1658308 : return out;
1803 : }
1804 :
1805 : /*
1806 : * Make copy of string with all trailing newline characters removed.
1807 : */
1808 : char *
1809 466 : pchomp(const char *in)
1810 : {
1811 : size_t n;
1812 :
1813 466 : n = strlen(in);
1814 932 : while (n > 0 && in[n - 1] == '\n')
1815 466 : n--;
1816 466 : return pnstrdup(in, n);
1817 : }
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