diff options
Diffstat (limited to 'src/include/utils/memutils.h')
| -rw-r--r-- | src/include/utils/memutils.h | 58 |
1 files changed, 36 insertions, 22 deletions
diff --git a/src/include/utils/memutils.h b/src/include/utils/memutils.h index 5223a4da395..58e816d8e97 100644 --- a/src/include/utils/memutils.h +++ b/src/include/utils/memutils.h @@ -45,27 +45,6 @@ #define AllocHugeSizeIsValid(size) ((Size) (size) <= MaxAllocHugeSize) -/* - * All chunks allocated by any memory context manager are required to be - * preceded by a StandardChunkHeader at a spacing of STANDARDCHUNKHEADERSIZE. - * A currently-allocated chunk must contain a backpointer to its owning - * context as well as the allocated size of the chunk. The backpointer is - * used by pfree() and repalloc() to find the context to call. The allocated - * size is not absolutely essential, but it's expected to be needed by any - * reasonable implementation. - */ -typedef struct StandardChunkHeader -{ - MemoryContext context; /* owning context */ - Size size; /* size of data space allocated in chunk */ -#ifdef MEMORY_CONTEXT_CHECKING - /* when debugging memory usage, also store actual requested size */ - Size requested_size; -#endif -} StandardChunkHeader; - -#define STANDARDCHUNKHEADERSIZE MAXALIGN(sizeof(StandardChunkHeader)) - /* * Standard top-level memory contexts. @@ -100,7 +79,6 @@ extern void MemoryContextDeleteChildren(MemoryContext context); extern void MemoryContextSetParent(MemoryContext context, MemoryContext new_parent); extern Size GetMemoryChunkSpace(void *pointer); -extern MemoryContext GetMemoryChunkContext(void *pointer); extern MemoryContext MemoryContextGetParent(MemoryContext context); extern bool MemoryContextIsEmpty(MemoryContext context); extern void MemoryContextStats(MemoryContext context); @@ -114,6 +92,42 @@ extern void MemoryContextCheck(MemoryContext context); extern bool MemoryContextContains(MemoryContext context, void *pointer); /* + * GetMemoryChunkContext + * Given a currently-allocated chunk, determine the context + * it belongs to. + * + * All chunks allocated by any memory context manager are required to be + * preceded by the corresponding MemoryContext stored, without padding, in the + * preceding sizeof(void*) bytes. A currently-allocated chunk must contain a + * backpointer to its owning context. The backpointer is used by pfree() and + * repalloc() to find the context to call. + */ +#ifndef FRONTEND +static inline MemoryContext +GetMemoryChunkContext(void *pointer) +{ + MemoryContext context; + + /* + * Try to detect bogus pointers handed to us, poorly though we can. + * Presumably, a pointer that isn't MAXALIGNED isn't pointing at an + * allocated chunk. + */ + Assert(pointer != NULL); + Assert(pointer == (void *) MAXALIGN(pointer)); + + /* + * OK, it's probably safe to look at the context. + */ + context = *(MemoryContext *) (((char *) pointer) - sizeof(void *)); + + AssertArg(MemoryContextIsValid(context)); + + return context; +} +#endif + +/* * This routine handles the context-type-independent part of memory * context creation. It's intended to be called from context-type- * specific creation routines, and noplace else. |