Files
openGauss-server/src/include/utils/palloc.h
April01xxx 5c25b5d90d 内存优化重构:在openGauss中新增了一套内存管理接口和MemoryContext类型
(详见opt_mcxt.cpp和opt_aset.cpp),并对MemoryContext的管理接口(如
reset、delete等操作)进行抽象,带来以下优势:
1. 新增的MemoryContext类型支持MemoryContext复用,减少频繁创建和销毁
MemoryContext的开销;
2. 新增的STANDARD_CONTEXT内存管理接口删除了内存跟踪统计操作,提升了
内存申请和释放时的性能。
2023-04-27 14:20:26 +08:00

390 lines
16 KiB
C++

/* -------------------------------------------------------------------------
*
* palloc.h
* openGauss memory allocator definitions.
*
* This file contains the basic memory allocation interface that is
* needed by almost every backend module. It is included directly by
* postgres.h, so the definitions here are automatically available
* everywhere. Keep it lean!
*
* Memory allocation occurs within "contexts". Every chunk obtained from
* palloc()/MemoryContextAlloc() is allocated within a specific context.
* The entire contents of a context can be freed easily and quickly by
* resetting or deleting the context --- this is both faster and less
* prone to memory-leakage bugs than releasing chunks individually.
* We organize contexts into context trees to allow fine-grain control
* over chunk lifetime while preserving the certainty that we will free
* everything that should be freed. See utils/mmgr/README for more info.
*
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/utils/palloc.h
*
* -------------------------------------------------------------------------
*/
#ifndef PALLOC_H
#define PALLOC_H
#ifndef FRONTEND_PARSER
#include "postgres.h"
#include "c.h"
#include "nodes/nodes.h"
#include "nodes/pg_list.h"
typedef struct MemoryContextData* MemoryContext;
/*
* MemoryContext
* A logical context in which memory allocations occur.
*
* MemoryContext itself is an abstract type that can have multiple
* implementations, though for now we have only AllocSetContext.
* The function pointers in MemoryContextMethods define one specific
* implementation of MemoryContext --- they are a virtual function table
* in C++ terms.
*
* Node types that are actual implementations of memory contexts must
* begin with the same fields as MemoryContext.
*
* Note: for largely historical reasons, typedef MemoryContext is a pointer
* to the context struct rather than the struct type itself.
*/
typedef struct MemoryContextMethods {
void* (*alloc)(MemoryContext context, Size align, Size size, const char* file, int line);
/* call this free_p in case someone #define's free() */
void (*free_p)(MemoryContext context, void* pointer);
void* (*realloc)(MemoryContext context, void* pointer, Size align, Size size, const char* file, int line);
void (*init)(MemoryContext context);
void (*reset)(MemoryContext context);
void (*delete_context)(MemoryContext context);
Size (*get_chunk_space)(MemoryContext context, void* pointer);
bool (*is_empty)(MemoryContext context);
void (*stats)(MemoryContext context, int level);
#ifdef MEMORY_CONTEXT_CHECKING
void (*check)(MemoryContext context);
#endif
} MemoryContextMethods;
/*
* McxtAllocationMethods
* A virtual function table for memory allocation from memory context.
*/
typedef struct McxtAllocationMethods {
void *(*alloc_from_context)(MemoryContext context, Size size, const char* file, int line);
void *(*alloc_from_context_debug)(MemoryContext context, Size size, const char* file, int line);
void *(*alloc_zero_from_context_debug)(MemoryContext context, Size size, const char* file, int line);
void *(*alloc_zero_aligned_from_context_debug)(MemoryContext context, Size size, const char* file, int line);
void *(*alloc_huge_from_context_debug)(MemoryContext context, Size size, const char* file, int line);
void *(*alloc_huge_zero_from_context_debug)(MemoryContext context, Size size, const char* file, int line);
void* (*alloc_extend_from_context_debug)(MemoryContext context, Size size, int flags, const char* file, int line);
char *(*strdup_from_context_debug)(MemoryContext context, const char* string, const char* file, int line);
void *(*alloc_extend)(Size size, int flags);
void *(*alloc_noexcept)(Size size);
} McxtAllocationMethods;
/*
* McxtOperationMethods
* A virtual function table for memory-context-type-independent functions.
*/
typedef struct McxtOperationMethods {
void (*mcxt_reset)(MemoryContext context);
void (*mcxt_delete)(MemoryContext context);
void (*mcxt_delete_children)(MemoryContext context, List* context_list);
void (*mcxt_destroy)(MemoryContext context);
void (*mcxt_reset_and_delete_children)(MemoryContext context);
void (*mcxt_set_parent)(MemoryContext context, MemoryContext new_parent);
#ifdef MEMORY_CONTEXT_CHECKING
void (*mcxt_check)(MemoryContext context, bool own_by_session);
#endif
} McxtOperationMethods;
typedef struct MemoryContextData {
NodeTag type; /* identifies exact kind of context */
bool is_sealed; /* sealed context prevent any memory change */
bool is_shared; /* context is shared by threads */
bool isReset; /* T = no space alloced since last reset */
bool allowInCritSection; /* allow palloc in critical section */
MemoryContextMethods* methods; /* virtual function table */
McxtAllocationMethods* alloc_methods;
McxtOperationMethods* mcxt_methods;
MemoryContext parent; /* NULL if no parent (toplevel context) */
MemoryContext firstchild; /* head of linked list of children */
MemoryContext prevchild; /* previous child of same parent */
MemoryContext nextchild; /* next child of same parent */
char* name; /* context name (just for debugging) */
pthread_rwlock_t lock; /* lock to protect members if the context is shared */
int level; /* context level */
uint64 session_id; /* session id of context owner */
ThreadId thread_id; /* thread id of context owner */
ListCell cell; /* cell to pointer to this context*/
} MemoryContextData;
/*
* CurrentMemoryContext is the default allocation context for palloc().
* We declare it here so that palloc() can be a macro. Avoid accessing it
* directly! Instead, use MemoryContextSwitchTo() to change the setting.
*/
#ifdef WIN32
extern THR_LOCAL MemoryContext CurrentMemoryContext;
extern THR_LOCAL MemoryContext SelfMemoryContext;
extern THR_LOCAL MemoryContext TopMemoryContext;
#else
extern THR_LOCAL PGDLLIMPORT MemoryContext CurrentMemoryContext;
extern THR_LOCAL PGDLLIMPORT MemoryContext SelfMemoryContext;
extern THR_LOCAL PGDLLIMPORT MemoryContext TopMemoryContext;
#endif /* WIN32 */
#ifdef MEMORY_CONTEXT_CHECKING
const uint64 BlkMagicNum = 0xDADADADADADADADA;
const uint32 PremagicNum = 0xBABABABA;
#endif
/*
* Flags for MemoryContextAllocExtended.
*/
#define MCXT_ALLOC_HUGE 0x01 /* allow huge allocation (> 1 GB) */
#define MCXT_ALLOC_NO_OOM 0x02 /* no failure if out-of-memory */
#define MCXT_ALLOC_ZERO 0x04 /* zero allocated memory */
#define ENABLE_MEMORY_PROTECT() (t_thrd.utils_cxt.memNeedProtect = true)
#define DISABLE_MEMORY_PROTECT() (t_thrd.utils_cxt.memNeedProtect = false)
/* Definition for the unchanged interfaces */
#ifndef MEMORY_CONTEXT_CHECKING
#define MemoryContextAlloc(context, size) \
(((MemoryContext)context)->alloc_methods->alloc_from_context(context, size, __FILE__, __LINE__))
#else
#define MemoryContextAlloc(context, size) \
(((MemoryContext)context)->alloc_methods->alloc_from_context_debug(context, size, __FILE__, __LINE__))
#endif /* MEMORY_CONTEXT_CHECKING */
#define MemoryContextAllocZero(context, size) \
(((MemoryContext)context)->alloc_methods->alloc_zero_from_context_debug(context, size, __FILE__, __LINE__))
#define MemoryContextAllocZeroAligned(context, size) \
(((MemoryContext)context)->alloc_methods->alloc_zero_aligned_from_context_debug(context, size, __FILE__, __LINE__))
#define MemoryContextAllocExtended(context, size, flags) \
(((MemoryContext)context)->alloc_methods->alloc_extend_from_context_debug(context, size, flags, __FILE__, __LINE__))
#define MemoryContextStrdup(context, str) \
(((MemoryContext)context)->alloc_methods->strdup_from_context_debug(context, str, __FILE__, __LINE__))
#define palloc_huge(context, size) \
(((MemoryContext)context)->alloc_methods->alloc_huge_from_context_debug(context, size, __FILE__, __LINE__))
#define palloc0_huge(context, size) \
(((MemoryContext)context)->alloc_methods->alloc_huge_zero_from_context_debug(context, size, __FILE__, __LINE__))
#ifndef FRONTEND
#define palloc(sz) \
(MemoryContextAlloc(CurrentMemoryContext, (sz)))
#define palloc_extended(size, flags) \
(CurrentMemoryContext->alloc_methods->alloc_extend(size, flags))
#endif
#define palloc0_noexcept(size) \
(CurrentMemoryContext->alloc_methods->alloc_noexcept(size))
#define palloc0(sz) MemoryContextAllocZero(CurrentMemoryContext, (sz))
#define selfpalloc(sz) MemoryContextAlloc(SelfMemoryContext, (sz))
#define selfpalloc0(sz) MemoryContextAllocZero(SelfMemoryContext, (sz))
#define selfpstrdup(str) MemoryContextStrdup(SelfMemoryContext, (str))
#define pstrdup(str) MemoryContextStrdup(CurrentMemoryContext, (str))
#define pstrdup_ext(str) \
(((str) == NULL) ? NULL : (pstrdup((const char*)(str))))
/*
* The result of palloc() is always word-aligned, so we can skip testing
* alignment of the pointer when deciding which MemSet variant to use.
* Note that this variant does not offer any advantage, and should not be
* used, unless its "sz" argument is a compile-time constant; therefore, the
* issue that it evaluates the argument multiple times isn't a problem in
* practice.
*/
#define palloc0fast(sz) \
(MemSetTest(0, sz) ? MemoryContextAllocZeroAligned(CurrentMemoryContext, sz) \
: MemoryContextAllocZero(CurrentMemoryContext, sz))
#define repalloc(pointer, size) \
repallocDebug(pointer, size, __FILE__, __LINE__)
#define repalloc_noexcept(pointer, size) \
repalloc_noexcept_Debug(pointer, size, __FILE__, __LINE__)
#define pnstrdup(in, len) \
pnstrdupDebug(in, len, __FILE__, __LINE__)
#define INSTANCE_GET_MEM_CXT_GROUP g_instance.mcxt_group->GetMemCxtGroup
#define THREAD_GET_MEM_CXT_GROUP t_thrd.mcxt_group->GetMemCxtGroup
#define SESS_GET_MEM_CXT_GROUP u_sess->mcxt_group->GetMemCxtGroup
/*
* Fundamental memory-allocation operations (more are in utils/memutils.h)
*/
extern void* MemoryAllocFromContext(MemoryContext context, Size size, const char* file, int line);
extern void* MemoryContextAllocDebug(MemoryContext context, Size size, const char* file, int line);
extern void* MemoryContextAllocHugeDebug(MemoryContext context, Size size, const char* file, int line);
extern void* MemoryContextAllocHugeZeroDebug(MemoryContext context, Size size, const char* file, int line);
extern void* repallocHugeDebug(void* pointer, Size size, const char* file, int line);
extern void* MemoryContextAllocZeroDebug(MemoryContext context, Size size, const char* file, int line);
extern void* MemoryContextAllocZeroAlignedDebug(MemoryContext context, Size size, const char* file, int line);
extern void* MemoryContextAllocExtendedDebug(MemoryContext context, Size size, int flags, const char* file, int line);
extern char* MemoryContextStrdupDebug(MemoryContext context, const char* string, const char* file, int line);
extern void* MemoryContextMemalignAllocDebug(MemoryContext context, Size align, Size size, const char* file, int line);
extern void MemoryContextMemalignFree(MemoryContext context, void* pointer);
extern void* std_palloc_extended(Size size, int flags);
extern void* std_palloc0_noexcept(Size size);
extern void* opt_MemoryAllocFromContext(MemoryContext context, Size size, const char* file, int line);
#define opt_MemoryContextAllocDebug(context, size, file, line) \
opt_MemoryAllocFromContext(context, size, file, line)
#define opt_MemoryContextAllocHugeDebug(context, size, file, line) \
opt_MemoryAllocFromContext(context, size, file, line)
extern void* opt_MemoryContextAllocHugeZeroDebug(MemoryContext context, Size size, const char* file, int line);
extern void* opt_MemoryContextAllocZeroDebug(MemoryContext context, Size size, const char* file, int line);
extern void* opt_MemoryContextAllocZeroAlignedDebug(MemoryContext context, Size size, const char* file, int line);
extern void* opt_MemoryContextAllocExtendedDebug(MemoryContext context, Size size, int flags, const char* file, int line);
extern char* opt_MemoryContextStrdupDebug(MemoryContext context, const char* string, const char* file, int line);
extern void* opt_palloc_extended(Size size, int flags);
extern void* opt_palloc0_noexcept(Size size);
#define repalloc_huge(pointer, size) repallocHugeDebug(pointer, size, __FILE__, __LINE__)
#define selfrepalloc(ptr, sz) repalloc((ptr), (sz))
extern THR_LOCAL MemoryContext AlignMemoryContext;
#define mem_align_alloc(align, size) \
MemoryContextMemalignAllocDebug(AlignMemoryContext, (align), (size), __FILE__, __LINE__)
#define mem_align_free(ptr) MemoryContextMemalignFree(AlignMemoryContext, (ptr))
extern void pfree(void* pointer);
extern void opt_pfree(void* pointer);
#define selfpfree(ptr) pfree((ptr))
template <typename T>
bool isConst(T& x)
{
return false;
}
template <typename T>
bool isConst(T const& x)
{
return true;
}
#define FREE_POINTER(ptr) \
do { \
if ((ptr) != NULL) { \
pfree((void*)ptr); \
if (!isConst(ptr)) \
(ptr) = NULL; \
} \
} while (0)
// call pfree() and set pointer to be NULL.
#define pfree_ext(__p) FREE_POINTER(__p)
extern void* repallocDebug(void* pointer, Size size, const char* file, int line);
extern void* opt_repallocDebug(void* pointer, Size size, const char* file, int line);
extern void* repalloc_noexcept_Debug(void* pointer, Size size, const char* file, int line);
extern void* opt_repalloc_noexcept_Debug(void* pointer, Size size, const char* file, int line);
/*
* MemoryContextSwitchTo can't be a macro in standard C compilers.
* But we can make it an inline function if the compiler supports it.
*
* This file has to be includable by some non-backend code such as
* pg_resetxlog, so don't expose the CurrentMemoryContext reference
* if FRONTEND is defined.
*/
#if defined(USE_INLINE) && !defined(FRONTEND)
static inline MemoryContext MemoryContextSwitchTo(MemoryContext context)
{
MemoryContext old = CurrentMemoryContext;
CurrentMemoryContext = context;
return old;
}
#else
extern MemoryContext MemoryContextSwitchTo(MemoryContext context);
#endif /* USE_INLINE && !FRONTEND */
/*
* These are like standard strdup() except the copied string is
* allocated in a context, not with malloc().
*/
extern char* MemoryContextStrdupDebug(MemoryContext context, const char* string, const char* file, int line);
extern char* pnstrdupDebug(const char* in, Size len, const char* file, int line);
extern void AllocSetCheckPointer(void* pointer);
#if defined(WIN32) || defined(__CYGWIN__)
extern void* pgport_palloc(Size sz);
extern char* pgport_pstrdup(const char* str);
extern void pgport_pfree(void* pointer);
#endif
#define New(pmc) new (pmc, __FILE__, __LINE__)
// BaseObject is a basic class
// All other class should inherit from BaseObject class which
// override operator new/delete.
//
class BaseObject {
public:
~BaseObject()
{}
void* operator new(size_t size, MemoryContextData* pmc, const char* file, int line)
{
return MemoryContextAllocDebug(pmc, size, file, line);
}
void* operator new[](size_t size, MemoryContextData* pmc, const char* file, int line)
{
return MemoryContextAllocDebug(pmc, size, file, line);
}
void operator delete(void* p)
{
pfree(p);
}
void operator delete[](void* p)
{
pfree(p);
}
};
/*
*It is used for delete object whose destructor is null and free memory in Destroy()
*_objptr can't include type change, for example (A*)b, that will lead to compile error in (_objptr) = NULL
*If _objptr include type change, please use DELETE_EX_TYPE to complete it.
*It is supplied easily for developers to refactor destructor in the future
*/
#define DELETE_EX(_objptr) \
do { \
(_objptr)->Destroy(); \
delete (_objptr); \
(_objptr) = NULL; \
} while (0)
// used for _objptr need to change to another type
#define DELETE_EX_TYPE(_objptr, _type) \
do { \
((_type*)(_objptr))->Destroy(); \
delete (_type*)(_objptr); \
(_objptr) = NULL; \
} while (0)
#define DELETE_EX2(_objptr) \
do { \
if ((_objptr) != nullptr) { \
delete (_objptr); \
(_objptr) = NULL; \
} \
} while (0)
#endif /* !FRONTEND_PARSER */
#endif /* PALLOC_H */