codekingpro/portable-devtools

1/*-------------------------------------------------------------------------2 *3 * memutils.h4 *	  This file contains declarations for memory allocation utility5 *	  functions.  These are functions that are not quite widely used6 *	  enough to justify going in utils/palloc.h, but are still part7 *	  of the API of the memory management subsystem.8 *9 *10 * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group11 * Portions Copyright (c) 1994, Regents of the University of California12 *13 * src/include/utils/memutils.h14 *15 *-------------------------------------------------------------------------16 */17#ifndef MEMUTILS_H18#define MEMUTILS_H19 20#include "nodes/memnodes.h"21 22 23/*24 * MaxAllocSize, MaxAllocHugeSize25 *		Quasi-arbitrary limits on size of allocations.26 *27 * Note:28 *		There is no guarantee that smaller allocations will succeed, but29 *		larger requests will be summarily denied.30 *31 * palloc() enforces MaxAllocSize, chosen to correspond to the limiting size32 * of varlena objects under TOAST.  See VARSIZE_4B() and related macros in33 * postgres.h.  Many datatypes assume that any allocatable size can be34 * represented in a varlena header.  This limit also permits a caller to use35 * an "int" variable for an index into or length of an allocation.  Callers36 * careful to avoid these hazards can access the higher limit with37 * MemoryContextAllocHuge().  Both limits permit code to assume that it may38 * compute twice an allocation's size without overflow.39 */40#define MaxAllocSize	((Size) 0x3fffffff) /* 1 gigabyte - 1 */41 42#define AllocSizeIsValid(size)	((Size) (size) <= MaxAllocSize)43 44/* Must be less than SIZE_MAX */45#define MaxAllocHugeSize	(SIZE_MAX / 2)46 47#define InvalidAllocSize	SIZE_MAX48 49#define AllocHugeSizeIsValid(size)	((Size) (size) <= MaxAllocHugeSize)50 51 52/*53 * Standard top-level memory contexts.54 *55 * Only TopMemoryContext and ErrorContext are initialized by56 * MemoryContextInit() itself.57 */58extern PGDLLIMPORT MemoryContext TopMemoryContext;59extern PGDLLIMPORT MemoryContext ErrorContext;60extern PGDLLIMPORT MemoryContext PostmasterContext;61extern PGDLLIMPORT MemoryContext CacheMemoryContext;62extern PGDLLIMPORT MemoryContext MessageContext;63extern PGDLLIMPORT MemoryContext TopTransactionContext;64extern PGDLLIMPORT MemoryContext CurTransactionContext;65 66/* This is a transient link to the active portal's memory context: */67extern PGDLLIMPORT MemoryContext PortalContext;68 69/* Backwards compatibility macro */70#define MemoryContextResetAndDeleteChildren(ctx) MemoryContextReset(ctx)71 72 73/*74 * Memory-context-type-independent functions in mcxt.c75 */76extern void MemoryContextInit(void);77extern void MemoryContextReset(MemoryContext context);78extern void MemoryContextDelete(MemoryContext context);79extern void MemoryContextResetOnly(MemoryContext context);80extern void MemoryContextResetChildren(MemoryContext context);81extern void MemoryContextDeleteChildren(MemoryContext context);82extern void MemoryContextSetIdentifier(MemoryContext context, const char *id);83extern void MemoryContextSetParent(MemoryContext context,84								   MemoryContext new_parent);85extern MemoryContext GetMemoryChunkContext(void *pointer);86extern Size GetMemoryChunkSpace(void *pointer);87extern MemoryContext MemoryContextGetParent(MemoryContext context);88extern bool MemoryContextIsEmpty(MemoryContext context);89extern Size MemoryContextMemAllocated(MemoryContext context, bool recurse);90extern void MemoryContextStats(MemoryContext context);91extern void MemoryContextStatsDetail(MemoryContext context, int max_children,92									 bool print_to_stderr);93extern void MemoryContextAllowInCriticalSection(MemoryContext context,94												bool allow);95 96#ifdef MEMORY_CONTEXT_CHECKING97extern void MemoryContextCheck(MemoryContext context);98#endif99 100/* Handy macro for copying and assigning context ID ... but note double eval */101#define MemoryContextCopyAndSetIdentifier(cxt, id) \102	MemoryContextSetIdentifier(cxt, MemoryContextStrdup(cxt, id))103 104extern void HandleLogMemoryContextInterrupt(void);105extern void ProcessLogMemoryContextInterrupt(void);106 107/*108 * Memory-context-type-specific functions109 */110 111/* aset.c */112extern MemoryContext AllocSetContextCreateInternal(MemoryContext parent,113												   const char *name,114												   Size minContextSize,115												   Size initBlockSize,116												   Size maxBlockSize);117 118/*119 * This wrapper macro exists to check for non-constant strings used as context120 * names; that's no longer supported.  (Use MemoryContextSetIdentifier if you121 * want to provide a variable identifier.)122 */123#ifdef HAVE__BUILTIN_CONSTANT_P124#define AllocSetContextCreate(parent, name, ...) \125	(StaticAssertExpr(__builtin_constant_p(name), \126					  "memory context names must be constant strings"), \127	 AllocSetContextCreateInternal(parent, name, __VA_ARGS__))128#else129#define AllocSetContextCreate \130	AllocSetContextCreateInternal131#endif132 133/* slab.c */134extern MemoryContext SlabContextCreate(MemoryContext parent,135									   const char *name,136									   Size blockSize,137									   Size chunkSize);138 139/* generation.c */140extern MemoryContext GenerationContextCreate(MemoryContext parent,141											 const char *name,142											 Size minContextSize,143											 Size initBlockSize,144											 Size maxBlockSize);145 146/*147 * Recommended default alloc parameters, suitable for "ordinary" contexts148 * that might hold quite a lot of data.149 */150#define ALLOCSET_DEFAULT_MINSIZE   0151#define ALLOCSET_DEFAULT_INITSIZE  (8 * 1024)152#define ALLOCSET_DEFAULT_MAXSIZE   (8 * 1024 * 1024)153#define ALLOCSET_DEFAULT_SIZES \154	ALLOCSET_DEFAULT_MINSIZE, ALLOCSET_DEFAULT_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE155 156/*157 * Recommended alloc parameters for "small" contexts that are never expected158 * to contain much data (for example, a context to contain a query plan).159 */160#define ALLOCSET_SMALL_MINSIZE	 0161#define ALLOCSET_SMALL_INITSIZE  (1 * 1024)162#define ALLOCSET_SMALL_MAXSIZE	 (8 * 1024)163#define ALLOCSET_SMALL_SIZES \164	ALLOCSET_SMALL_MINSIZE, ALLOCSET_SMALL_INITSIZE, ALLOCSET_SMALL_MAXSIZE165 166/*167 * Recommended alloc parameters for contexts that should start out small,168 * but might sometimes grow big.169 */170#define ALLOCSET_START_SMALL_SIZES \171	ALLOCSET_SMALL_MINSIZE, ALLOCSET_SMALL_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE172 173 174/*175 * Threshold above which a request in an AllocSet context is certain to be176 * allocated separately (and thereby have constant allocation overhead).177 * Few callers should be interested in this, but tuplesort/tuplestore need178 * to know it.179 */180#define ALLOCSET_SEPARATE_THRESHOLD  8192181 182#define SLAB_DEFAULT_BLOCK_SIZE		(8 * 1024)183#define SLAB_LARGE_BLOCK_SIZE		(8 * 1024 * 1024)184 185#endif							/* MEMUTILS_H */186