Adding upstream version 16.2.upstream/16.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 185 insertions, 0 deletions

diff --git a/src/include/utils/memutils.h b/src/include/utils/memutils.h
new file mode 100644
index 0000000..21640d6
--- /dev/null
+++ b/src/include/utils/memutils.h
@@ -0,0 +1,185 @@
+/*-------------------------------------------------------------------------
+ *
+ * memutils.h
+ *	  This file contains declarations for memory allocation utility
+ *	  functions.  These are functions that are not quite widely used
+ *	  enough to justify going in utils/palloc.h, but are still part
+ *	  of the API of the memory management subsystem.
+ *
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/utils/memutils.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef MEMUTILS_H
+#define MEMUTILS_H
+
+#include "nodes/memnodes.h"
+
+
+/*
+ * MaxAllocSize, MaxAllocHugeSize
+ *		Quasi-arbitrary limits on size of allocations.
+ *
+ * Note:
+ *		There is no guarantee that smaller allocations will succeed, but
+ *		larger requests will be summarily denied.
+ *
+ * palloc() enforces MaxAllocSize, chosen to correspond to the limiting size
+ * of varlena objects under TOAST.  See VARSIZE_4B() and related macros in
+ * postgres.h.  Many datatypes assume that any allocatable size can be
+ * represented in a varlena header.  This limit also permits a caller to use
+ * an "int" variable for an index into or length of an allocation.  Callers
+ * careful to avoid these hazards can access the higher limit with
+ * MemoryContextAllocHuge().  Both limits permit code to assume that it may
+ * compute twice an allocation's size without overflow.
+ */
+#define MaxAllocSize	((Size) 0x3fffffff) /* 1 gigabyte - 1 */
+
+#define AllocSizeIsValid(size)	((Size) (size) <= MaxAllocSize)
+
+/* Must be less than SIZE_MAX */
+#define MaxAllocHugeSize	(SIZE_MAX / 2)
+
+#define InvalidAllocSize	SIZE_MAX
+
+#define AllocHugeSizeIsValid(size)	((Size) (size) <= MaxAllocHugeSize)
+
+
+/*
+ * Standard top-level memory contexts.
+ *
+ * Only TopMemoryContext and ErrorContext are initialized by
+ * MemoryContextInit() itself.
+ */
+extern PGDLLIMPORT MemoryContext TopMemoryContext;
+extern PGDLLIMPORT MemoryContext ErrorContext;
+extern PGDLLIMPORT MemoryContext PostmasterContext;
+extern PGDLLIMPORT MemoryContext CacheMemoryContext;
+extern PGDLLIMPORT MemoryContext MessageContext;
+extern PGDLLIMPORT MemoryContext TopTransactionContext;
+extern PGDLLIMPORT MemoryContext CurTransactionContext;
+
+/* This is a transient link to the active portal's memory context: */
+extern PGDLLIMPORT MemoryContext PortalContext;
+
+/* Backwards compatibility macro */
+#define MemoryContextResetAndDeleteChildren(ctx) MemoryContextReset(ctx)
+
+
+/*
+ * Memory-context-type-independent functions in mcxt.c
+ */
+extern void MemoryContextInit(void);
+extern void MemoryContextReset(MemoryContext context);
+extern void MemoryContextDelete(MemoryContext context);
+extern void MemoryContextResetOnly(MemoryContext context);
+extern void MemoryContextResetChildren(MemoryContext context);
+extern void MemoryContextDeleteChildren(MemoryContext context);
+extern void MemoryContextSetIdentifier(MemoryContext context, const char *id);
+extern void MemoryContextSetParent(MemoryContext context,
+								   MemoryContext new_parent);
+extern MemoryContext GetMemoryChunkContext(void *pointer);
+extern Size GetMemoryChunkSpace(void *pointer);
+extern MemoryContext MemoryContextGetParent(MemoryContext context);
+extern bool MemoryContextIsEmpty(MemoryContext context);
+extern Size MemoryContextMemAllocated(MemoryContext context, bool recurse);
+extern void MemoryContextStats(MemoryContext context);
+extern void MemoryContextStatsDetail(MemoryContext context, int max_children,
+									 bool print_to_stderr);
+extern void MemoryContextAllowInCriticalSection(MemoryContext context,
+												bool allow);
+
+#ifdef MEMORY_CONTEXT_CHECKING
+extern void MemoryContextCheck(MemoryContext context);
+#endif
+
+/* Handy macro for copying and assigning context ID ... but note double eval */
+#define MemoryContextCopyAndSetIdentifier(cxt, id) \
+	MemoryContextSetIdentifier(cxt, MemoryContextStrdup(cxt, id))
+
+extern void HandleLogMemoryContextInterrupt(void);
+extern void ProcessLogMemoryContextInterrupt(void);
+
+/*
+ * Memory-context-type-specific functions
+ */
+
+/* aset.c */
+extern MemoryContext AllocSetContextCreateInternal(MemoryContext parent,
+												   const char *name,
+												   Size minContextSize,
+												   Size initBlockSize,
+												   Size maxBlockSize);
+
+/*
+ * This wrapper macro exists to check for non-constant strings used as context
+ * names; that's no longer supported.  (Use MemoryContextSetIdentifier if you
+ * want to provide a variable identifier.)
+ */
+#ifdef HAVE__BUILTIN_CONSTANT_P
+#define AllocSetContextCreate(parent, name, ...) \
+	(StaticAssertExpr(__builtin_constant_p(name), \
+					  "memory context names must be constant strings"), \
+	 AllocSetContextCreateInternal(parent, name, __VA_ARGS__))
+#else
+#define AllocSetContextCreate \
+	AllocSetContextCreateInternal
+#endif
+
+/* slab.c */
+extern MemoryContext SlabContextCreate(MemoryContext parent,
+									   const char *name,
+									   Size blockSize,
+									   Size chunkSize);
+
+/* generation.c */
+extern MemoryContext GenerationContextCreate(MemoryContext parent,
+											 const char *name,
+											 Size minContextSize,
+											 Size initBlockSize,
+											 Size maxBlockSize);
+
+/*
+ * Recommended default alloc parameters, suitable for "ordinary" contexts
+ * that might hold quite a lot of data.
+ */
+#define ALLOCSET_DEFAULT_MINSIZE   0
+#define ALLOCSET_DEFAULT_INITSIZE  (8 * 1024)
+#define ALLOCSET_DEFAULT_MAXSIZE   (8 * 1024 * 1024)
+#define ALLOCSET_DEFAULT_SIZES \
+	ALLOCSET_DEFAULT_MINSIZE, ALLOCSET_DEFAULT_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE
+
+/*
+ * Recommended alloc parameters for "small" contexts that are never expected
+ * to contain much data (for example, a context to contain a query plan).
+ */
+#define ALLOCSET_SMALL_MINSIZE	 0
+#define ALLOCSET_SMALL_INITSIZE  (1 * 1024)
+#define ALLOCSET_SMALL_MAXSIZE	 (8 * 1024)
+#define ALLOCSET_SMALL_SIZES \
+	ALLOCSET_SMALL_MINSIZE, ALLOCSET_SMALL_INITSIZE, ALLOCSET_SMALL_MAXSIZE
+
+/*
+ * Recommended alloc parameters for contexts that should start out small,
+ * but might sometimes grow big.
+ */
+#define ALLOCSET_START_SMALL_SIZES \
+	ALLOCSET_SMALL_MINSIZE, ALLOCSET_SMALL_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE
+
+
+/*
+ * Threshold above which a request in an AllocSet context is certain to be
+ * allocated separately (and thereby have constant allocation overhead).
+ * Few callers should be interested in this, but tuplesort/tuplestore need
+ * to know it.
+ */
+#define ALLOCSET_SEPARATE_THRESHOLD  8192
+
+#define SLAB_DEFAULT_BLOCK_SIZE		(8 * 1024)
+#define SLAB_LARGE_BLOCK_SIZE		(8 * 1024 * 1024)
+
+#endif							/* MEMUTILS_H */