185 lines
6.5 KiB
C
185 lines
6.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* memutils.h
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* This file contains declarations for memory allocation utility
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* functions. These are functions that are not quite widely used
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* enough to justify going in utils/palloc.h, but are still part
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* of the API of the memory management subsystem.
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*
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*
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* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/utils/memutils.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef MEMUTILS_H
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#define MEMUTILS_H
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#include "nodes/memnodes.h"
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/*
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* MaxAllocSize, MaxAllocHugeSize
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* Quasi-arbitrary limits on size of allocations.
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*
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* Note:
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* There is no guarantee that smaller allocations will succeed, but
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* larger requests will be summarily denied.
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*
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* palloc() enforces MaxAllocSize, chosen to correspond to the limiting size
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* of varlena objects under TOAST. See VARSIZE_4B() and related macros in
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* postgres.h. Many datatypes assume that any allocatable size can be
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* represented in a varlena header. This limit also permits a caller to use
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* an "int" variable for an index into or length of an allocation. Callers
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* careful to avoid these hazards can access the higher limit with
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* MemoryContextAllocHuge(). Both limits permit code to assume that it may
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* compute twice an allocation's size without overflow.
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*/
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#define MaxAllocSize ((Size) 0x3fffffff) /* 1 gigabyte - 1 */
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#define AllocSizeIsValid(size) ((Size) (size) <= MaxAllocSize)
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/* Must be less than SIZE_MAX */
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#define MaxAllocHugeSize (SIZE_MAX / 2)
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#define InvalidAllocSize SIZE_MAX
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#define AllocHugeSizeIsValid(size) ((Size) (size) <= MaxAllocHugeSize)
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/*
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* Standard top-level memory contexts.
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*
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* Only TopMemoryContext and ErrorContext are initialized by
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* MemoryContextInit() itself.
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*/
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extern PGDLLIMPORT MemoryContext TopMemoryContext;
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extern PGDLLIMPORT MemoryContext ErrorContext;
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extern PGDLLIMPORT MemoryContext PostmasterContext;
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extern PGDLLIMPORT MemoryContext CacheMemoryContext;
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extern PGDLLIMPORT MemoryContext MessageContext;
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extern PGDLLIMPORT MemoryContext TopTransactionContext;
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extern PGDLLIMPORT MemoryContext CurTransactionContext;
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/* This is a transient link to the active portal's memory context: */
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extern PGDLLIMPORT MemoryContext PortalContext;
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/*
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* Memory-context-type-independent functions in mcxt.c
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*/
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extern void MemoryContextInit(void);
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extern void MemoryContextReset(MemoryContext context);
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extern void MemoryContextDelete(MemoryContext context);
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extern void MemoryContextResetOnly(MemoryContext context);
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extern void MemoryContextResetChildren(MemoryContext context);
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extern void MemoryContextDeleteChildren(MemoryContext context);
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extern void MemoryContextSetIdentifier(MemoryContext context, const char *id);
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extern void MemoryContextSetParent(MemoryContext context,
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MemoryContext new_parent);
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extern MemoryContext GetMemoryChunkContext(void *pointer);
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extern Size GetMemoryChunkSpace(void *pointer);
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extern MemoryContext MemoryContextGetParent(MemoryContext context);
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extern bool MemoryContextIsEmpty(MemoryContext context);
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extern Size MemoryContextMemAllocated(MemoryContext context, bool recurse);
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extern void MemoryContextMemConsumed(MemoryContext context,
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MemoryContextCounters *consumed);
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extern void MemoryContextStats(MemoryContext context);
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extern void MemoryContextStatsDetail(MemoryContext context, int max_children,
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bool print_to_stderr);
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extern void MemoryContextAllowInCriticalSection(MemoryContext context,
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bool allow);
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#ifdef MEMORY_CONTEXT_CHECKING
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extern void MemoryContextCheck(MemoryContext context);
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#endif
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/* Handy macro for copying and assigning context ID ... but note double eval */
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#define MemoryContextCopyAndSetIdentifier(cxt, id) \
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MemoryContextSetIdentifier(cxt, MemoryContextStrdup(cxt, id))
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extern void HandleLogMemoryContextInterrupt(void);
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extern void ProcessLogMemoryContextInterrupt(void);
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/*
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* Memory-context-type-specific functions
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*/
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/* aset.c */
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extern MemoryContext AllocSetContextCreateInternal(MemoryContext parent,
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const char *name,
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Size minContextSize,
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Size initBlockSize,
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Size maxBlockSize);
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/*
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* This wrapper macro exists to check for non-constant strings used as context
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* names; that's no longer supported. (Use MemoryContextSetIdentifier if you
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* want to provide a variable identifier.)
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*/
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#ifdef HAVE__BUILTIN_CONSTANT_P
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#define AllocSetContextCreate(parent, name, ...) \
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(StaticAssertExpr(__builtin_constant_p(name), \
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"memory context names must be constant strings"), \
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AllocSetContextCreateInternal(parent, name, __VA_ARGS__))
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#else
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#define AllocSetContextCreate \
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AllocSetContextCreateInternal
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#endif
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/* slab.c */
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extern MemoryContext SlabContextCreate(MemoryContext parent,
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const char *name,
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Size blockSize,
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Size chunkSize);
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/* generation.c */
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extern MemoryContext GenerationContextCreate(MemoryContext parent,
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const char *name,
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Size minContextSize,
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Size initBlockSize,
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Size maxBlockSize);
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/*
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* Recommended default alloc parameters, suitable for "ordinary" contexts
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* that might hold quite a lot of data.
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*/
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#define ALLOCSET_DEFAULT_MINSIZE 0
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#define ALLOCSET_DEFAULT_INITSIZE (8 * 1024)
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#define ALLOCSET_DEFAULT_MAXSIZE (8 * 1024 * 1024)
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#define ALLOCSET_DEFAULT_SIZES \
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ALLOCSET_DEFAULT_MINSIZE, ALLOCSET_DEFAULT_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE
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/*
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* Recommended alloc parameters for "small" contexts that are never expected
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* to contain much data (for example, a context to contain a query plan).
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*/
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#define ALLOCSET_SMALL_MINSIZE 0
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#define ALLOCSET_SMALL_INITSIZE (1 * 1024)
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#define ALLOCSET_SMALL_MAXSIZE (8 * 1024)
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#define ALLOCSET_SMALL_SIZES \
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ALLOCSET_SMALL_MINSIZE, ALLOCSET_SMALL_INITSIZE, ALLOCSET_SMALL_MAXSIZE
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/*
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* Recommended alloc parameters for contexts that should start out small,
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* but might sometimes grow big.
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*/
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#define ALLOCSET_START_SMALL_SIZES \
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ALLOCSET_SMALL_MINSIZE, ALLOCSET_SMALL_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE
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/*
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* Threshold above which a request in an AllocSet context is certain to be
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* allocated separately (and thereby have constant allocation overhead).
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* Few callers should be interested in this, but tuplesort/tuplestore need
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* to know it.
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*/
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#define ALLOCSET_SEPARATE_THRESHOLD 8192
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#define SLAB_DEFAULT_BLOCK_SIZE (8 * 1024)
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#define SLAB_LARGE_BLOCK_SIZE (8 * 1024 * 1024)
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#endif /* MEMUTILS_H */
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