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cpython/Objects/obmalloc.c

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/* Python's malloc wrappers (see pymem.h) */
#include "Python.h"
#include "pycore_code.h" // stats
#include "pycore_object.h" // _PyDebugAllocatorStats() definition
#include "pycore_obmalloc.h"
#include "pycore_pyerrors.h" // _Py_FatalErrorFormat()
#include "pycore_pymem.h"
#include "pycore_pystate.h" // _PyInterpreterState_GET
#include <stdlib.h> // malloc()
#include <stdbool.h>
#undef uint
#define uint pymem_uint
/* Defined in tracemalloc.c */
extern void _PyMem_DumpTraceback(int fd, const void *ptr);
static void _PyObject_DebugDumpAddress(const void *p);
static void _PyMem_DebugCheckAddress(const char *func, char api_id, const void *p);
static void set_up_debug_hooks_domain_unlocked(PyMemAllocatorDomain domain);
static void set_up_debug_hooks_unlocked(void);
static void get_allocator_unlocked(PyMemAllocatorDomain, PyMemAllocatorEx *);
static void set_allocator_unlocked(PyMemAllocatorDomain, PyMemAllocatorEx *);
/***************************************/
/* low-level allocator implementations */
/***************************************/
/* the default raw allocator (wraps malloc) */
void *
_PyMem_RawMalloc(void *Py_UNUSED(ctx), size_t size)
{
/* PyMem_RawMalloc(0) means malloc(1). Some systems would return NULL
for malloc(0), which would be treated as an error. Some platforms would
return a pointer with no memory behind it, which would break pymalloc.
To solve these problems, allocate an extra byte. */
if (size == 0)
size = 1;
return malloc(size);
}
void *
_PyMem_RawCalloc(void *Py_UNUSED(ctx), size_t nelem, size_t elsize)
{
/* PyMem_RawCalloc(0, 0) means calloc(1, 1). Some systems would return NULL
for calloc(0, 0), which would be treated as an error. Some platforms
would return a pointer with no memory behind it, which would break
pymalloc. To solve these problems, allocate an extra byte. */
if (nelem == 0 || elsize == 0) {
nelem = 1;
elsize = 1;
}
return calloc(nelem, elsize);
}
void *
_PyMem_RawRealloc(void *Py_UNUSED(ctx), void *ptr, size_t size)
{
if (size == 0)
size = 1;
return realloc(ptr, size);
}
void
_PyMem_RawFree(void *Py_UNUSED(ctx), void *ptr)
{
free(ptr);
}
#define MALLOC_ALLOC {NULL, _PyMem_RawMalloc, _PyMem_RawCalloc, _PyMem_RawRealloc, _PyMem_RawFree}
#define PYRAW_ALLOC MALLOC_ALLOC
/* the default object allocator */
// The actual implementation is further down.
#ifdef WITH_PYMALLOC
void* _PyObject_Malloc(void *ctx, size_t size);
void* _PyObject_Calloc(void *ctx, size_t nelem, size_t elsize);
void _PyObject_Free(void *ctx, void *p);
void* _PyObject_Realloc(void *ctx, void *ptr, size_t size);
# define PYMALLOC_ALLOC {NULL, _PyObject_Malloc, _PyObject_Calloc, _PyObject_Realloc, _PyObject_Free}
# define PYOBJ_ALLOC PYMALLOC_ALLOC
#else
# define PYOBJ_ALLOC MALLOC_ALLOC
#endif // WITH_PYMALLOC
#define PYMEM_ALLOC PYOBJ_ALLOC
/* the default debug allocators */
// The actual implementation is further down.
void* _PyMem_DebugRawMalloc(void *ctx, size_t size);
void* _PyMem_DebugRawCalloc(void *ctx, size_t nelem, size_t elsize);
void* _PyMem_DebugRawRealloc(void *ctx, void *ptr, size_t size);
void _PyMem_DebugRawFree(void *ctx, void *ptr);
void* _PyMem_DebugMalloc(void *ctx, size_t size);
void* _PyMem_DebugCalloc(void *ctx, size_t nelem, size_t elsize);
void* _PyMem_DebugRealloc(void *ctx, void *ptr, size_t size);
void _PyMem_DebugFree(void *ctx, void *p);
#define PYDBGRAW_ALLOC \
{&_PyRuntime.allocators.debug.raw, _PyMem_DebugRawMalloc, _PyMem_DebugRawCalloc, _PyMem_DebugRawRealloc, _PyMem_DebugRawFree}
#define PYDBGMEM_ALLOC \
{&_PyRuntime.allocators.debug.mem, _PyMem_DebugMalloc, _PyMem_DebugCalloc, _PyMem_DebugRealloc, _PyMem_DebugFree}
#define PYDBGOBJ_ALLOC \
{&_PyRuntime.allocators.debug.obj, _PyMem_DebugMalloc, _PyMem_DebugCalloc, _PyMem_DebugRealloc, _PyMem_DebugFree}
/* the low-level virtual memory allocator */
#ifdef WITH_PYMALLOC
# ifdef MS_WINDOWS
# include <windows.h>
# elif defined(HAVE_MMAP)
# include <sys/mman.h>
# ifdef MAP_ANONYMOUS
# define ARENAS_USE_MMAP
# endif
# endif
#endif
void *
_PyMem_ArenaAlloc(void *Py_UNUSED(ctx), size_t size)
{
#ifdef MS_WINDOWS
return VirtualAlloc(NULL, size,
MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
#elif defined(ARENAS_USE_MMAP)
void *ptr;
ptr = mmap(NULL, size, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if (ptr == MAP_FAILED)
return NULL;
assert(ptr != NULL);
return ptr;
#else
return malloc(size);
#endif
}
void
_PyMem_ArenaFree(void *Py_UNUSED(ctx), void *ptr,
#if defined(ARENAS_USE_MMAP)
size_t size
#else
size_t Py_UNUSED(size)
#endif
)
{
#ifdef MS_WINDOWS
VirtualFree(ptr, 0, MEM_RELEASE);
#elif defined(ARENAS_USE_MMAP)
munmap(ptr, size);
#else
free(ptr);
#endif
}
/*******************************************/
/* end low-level allocator implementations */
/*******************************************/
#if defined(__has_feature) /* Clang */
# if __has_feature(address_sanitizer) /* is ASAN enabled? */
# define _Py_NO_SANITIZE_ADDRESS \
__attribute__((no_sanitize("address")))
# endif
# if __has_feature(thread_sanitizer) /* is TSAN enabled? */
# define _Py_NO_SANITIZE_THREAD __attribute__((no_sanitize_thread))
# endif
# if __has_feature(memory_sanitizer) /* is MSAN enabled? */
# define _Py_NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
# endif
#elif defined(__GNUC__)
# if defined(__SANITIZE_ADDRESS__) /* GCC 4.8+, is ASAN enabled? */
# define _Py_NO_SANITIZE_ADDRESS \
__attribute__((no_sanitize_address))
# endif
// TSAN is supported since GCC 5.1, but __SANITIZE_THREAD__ macro
// is provided only since GCC 7.
# if __GNUC__ > 5 || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
# define _Py_NO_SANITIZE_THREAD __attribute__((no_sanitize_thread))
# endif
#endif
#ifndef _Py_NO_SANITIZE_ADDRESS
# define _Py_NO_SANITIZE_ADDRESS
#endif
#ifndef _Py_NO_SANITIZE_THREAD
# define _Py_NO_SANITIZE_THREAD
#endif
#ifndef _Py_NO_SANITIZE_MEMORY
# define _Py_NO_SANITIZE_MEMORY
#endif
#define ALLOCATORS_MUTEX (_PyRuntime.allocators.mutex)
#define _PyMem_Raw (_PyRuntime.allocators.standard.raw)
#define _PyMem (_PyRuntime.allocators.standard.mem)
#define _PyObject (_PyRuntime.allocators.standard.obj)
#define _PyMem_Debug (_PyRuntime.allocators.debug)
#define _PyObject_Arena (_PyRuntime.allocators.obj_arena)
/***************************/
/* managing the allocators */
/***************************/
static int
set_default_allocator_unlocked(PyMemAllocatorDomain domain, int debug,
PyMemAllocatorEx *old_alloc)
{
if (old_alloc != NULL) {
get_allocator_unlocked(domain, old_alloc);
}
PyMemAllocatorEx new_alloc;
switch(domain)
{
case PYMEM_DOMAIN_RAW:
new_alloc = (PyMemAllocatorEx)PYRAW_ALLOC;
break;
case PYMEM_DOMAIN_MEM:
new_alloc = (PyMemAllocatorEx)PYMEM_ALLOC;
break;
case PYMEM_DOMAIN_OBJ:
new_alloc = (PyMemAllocatorEx)PYOBJ_ALLOC;
break;
default:
/* unknown domain */
return -1;
}
set_allocator_unlocked(domain, &new_alloc);
if (debug) {
set_up_debug_hooks_domain_unlocked(domain);
}
return 0;
}
#ifdef Py_DEBUG
static const int pydebug = 1;
#else
static const int pydebug = 0;
#endif
int
_PyMem_SetDefaultAllocator(PyMemAllocatorDomain domain,
PyMemAllocatorEx *old_alloc)
{
if (ALLOCATORS_MUTEX == NULL) {
/* The runtime must be initializing. */
return set_default_allocator_unlocked(domain, pydebug, old_alloc);
}
PyThread_acquire_lock(ALLOCATORS_MUTEX, WAIT_LOCK);
int res = set_default_allocator_unlocked(domain, pydebug, old_alloc);
PyThread_release_lock(ALLOCATORS_MUTEX);
return res;
}
int
_PyMem_GetAllocatorName(const char *name, PyMemAllocatorName *allocator)
{
if (name == NULL || *name == '\0') {
/* PYTHONMALLOC is empty or is not set or ignored (-E/-I command line
nameions): use default memory allocators */
*allocator = PYMEM_ALLOCATOR_DEFAULT;
}
else if (strcmp(name, "default") == 0) {
*allocator = PYMEM_ALLOCATOR_DEFAULT;
}
else if (strcmp(name, "debug") == 0) {
*allocator = PYMEM_ALLOCATOR_DEBUG;
}
#ifdef WITH_PYMALLOC
else if (strcmp(name, "pymalloc") == 0) {
*allocator = PYMEM_ALLOCATOR_PYMALLOC;
}
else if (strcmp(name, "pymalloc_debug") == 0) {
*allocator = PYMEM_ALLOCATOR_PYMALLOC_DEBUG;
}
#endif
else if (strcmp(name, "malloc") == 0) {
*allocator = PYMEM_ALLOCATOR_MALLOC;
}
else if (strcmp(name, "malloc_debug") == 0) {
*allocator = PYMEM_ALLOCATOR_MALLOC_DEBUG;
}
else {
/* unknown allocator */
return -1;
}
return 0;
}
static int
set_up_allocators_unlocked(PyMemAllocatorName allocator)
{
switch (allocator) {
case PYMEM_ALLOCATOR_NOT_SET:
/* do nothing */
break;
case PYMEM_ALLOCATOR_DEFAULT:
(void)set_default_allocator_unlocked(PYMEM_DOMAIN_RAW, pydebug, NULL);
(void)set_default_allocator_unlocked(PYMEM_DOMAIN_MEM, pydebug, NULL);
(void)set_default_allocator_unlocked(PYMEM_DOMAIN_OBJ, pydebug, NULL);
break;
case PYMEM_ALLOCATOR_DEBUG:
(void)set_default_allocator_unlocked(PYMEM_DOMAIN_RAW, 1, NULL);
(void)set_default_allocator_unlocked(PYMEM_DOMAIN_MEM, 1, NULL);
(void)set_default_allocator_unlocked(PYMEM_DOMAIN_OBJ, 1, NULL);
break;
#ifdef WITH_PYMALLOC
case PYMEM_ALLOCATOR_PYMALLOC:
case PYMEM_ALLOCATOR_PYMALLOC_DEBUG:
{
PyMemAllocatorEx malloc_alloc = MALLOC_ALLOC;
set_allocator_unlocked(PYMEM_DOMAIN_RAW, &malloc_alloc);
PyMemAllocatorEx pymalloc = PYMALLOC_ALLOC;
set_allocator_unlocked(PYMEM_DOMAIN_MEM, &pymalloc);
set_allocator_unlocked(PYMEM_DOMAIN_OBJ, &pymalloc);
if (allocator == PYMEM_ALLOCATOR_PYMALLOC_DEBUG) {
set_up_debug_hooks_unlocked();
}
break;
}
#endif
case PYMEM_ALLOCATOR_MALLOC:
case PYMEM_ALLOCATOR_MALLOC_DEBUG:
{
PyMemAllocatorEx malloc_alloc = MALLOC_ALLOC;
set_allocator_unlocked(PYMEM_DOMAIN_RAW, &malloc_alloc);
set_allocator_unlocked(PYMEM_DOMAIN_MEM, &malloc_alloc);
set_allocator_unlocked(PYMEM_DOMAIN_OBJ, &malloc_alloc);
if (allocator == PYMEM_ALLOCATOR_MALLOC_DEBUG) {
set_up_debug_hooks_unlocked();
}
break;
}
default:
/* unknown allocator */
return -1;
}
return 0;
}
int
_PyMem_SetupAllocators(PyMemAllocatorName allocator)
{
PyThread_acquire_lock(ALLOCATORS_MUTEX, WAIT_LOCK);
int res = set_up_allocators_unlocked(allocator);
PyThread_release_lock(ALLOCATORS_MUTEX);
return res;
}
static int
pymemallocator_eq(PyMemAllocatorEx *a, PyMemAllocatorEx *b)
{
return (memcmp(a, b, sizeof(PyMemAllocatorEx)) == 0);
}
static const char*
get_current_allocator_name_unlocked(void)
{
PyMemAllocatorEx malloc_alloc = MALLOC_ALLOC;
#ifdef WITH_PYMALLOC
PyMemAllocatorEx pymalloc = PYMALLOC_ALLOC;
#endif
if (pymemallocator_eq(&_PyMem_Raw, &malloc_alloc) &&
pymemallocator_eq(&_PyMem, &malloc_alloc) &&
pymemallocator_eq(&_PyObject, &malloc_alloc))
{
return "malloc";
}
#ifdef WITH_PYMALLOC
if (pymemallocator_eq(&_PyMem_Raw, &malloc_alloc) &&
pymemallocator_eq(&_PyMem, &pymalloc) &&
pymemallocator_eq(&_PyObject, &pymalloc))
{
return "pymalloc";
}
#endif
PyMemAllocatorEx dbg_raw = PYDBGRAW_ALLOC;
PyMemAllocatorEx dbg_mem = PYDBGMEM_ALLOC;
PyMemAllocatorEx dbg_obj = PYDBGOBJ_ALLOC;
if (pymemallocator_eq(&_PyMem_Raw, &dbg_raw) &&
pymemallocator_eq(&_PyMem, &dbg_mem) &&
pymemallocator_eq(&_PyObject, &dbg_obj))
{
/* Debug hooks installed */
if (pymemallocator_eq(&_PyMem_Debug.raw.alloc, &malloc_alloc) &&
pymemallocator_eq(&_PyMem_Debug.mem.alloc, &malloc_alloc) &&
pymemallocator_eq(&_PyMem_Debug.obj.alloc, &malloc_alloc))
{
return "malloc_debug";
}
#ifdef WITH_PYMALLOC
if (pymemallocator_eq(&_PyMem_Debug.raw.alloc, &malloc_alloc) &&
pymemallocator_eq(&_PyMem_Debug.mem.alloc, &pymalloc) &&
pymemallocator_eq(&_PyMem_Debug.obj.alloc, &pymalloc))
{
return "pymalloc_debug";
}
#endif
}
return NULL;
}
const char*
_PyMem_GetCurrentAllocatorName(void)
{
PyThread_acquire_lock(ALLOCATORS_MUTEX, WAIT_LOCK);
const char *name = get_current_allocator_name_unlocked();
PyThread_release_lock(ALLOCATORS_MUTEX);
return name;
}
#ifdef WITH_PYMALLOC
static int
_PyMem_DebugEnabled(void)
{
return (_PyObject.malloc == _PyMem_DebugMalloc);
}
static int
_PyMem_PymallocEnabled(void)
{
if (_PyMem_DebugEnabled()) {
return (_PyMem_Debug.obj.alloc.malloc == _PyObject_Malloc);
}
else {
return (_PyObject.malloc == _PyObject_Malloc);
}
}
#endif
static void
set_up_debug_hooks_domain_unlocked(PyMemAllocatorDomain domain)
{
PyMemAllocatorEx alloc;
if (domain == PYMEM_DOMAIN_RAW) {
if (_PyMem_Raw.malloc == _PyMem_DebugRawMalloc) {
return;
}
get_allocator_unlocked(domain, &_PyMem_Debug.raw.alloc);
alloc.ctx = &_PyMem_Debug.raw;
alloc.malloc = _PyMem_DebugRawMalloc;
alloc.calloc = _PyMem_DebugRawCalloc;
alloc.realloc = _PyMem_DebugRawRealloc;
alloc.free = _PyMem_DebugRawFree;
set_allocator_unlocked(domain, &alloc);
}
else if (domain == PYMEM_DOMAIN_MEM) {
if (_PyMem.malloc == _PyMem_DebugMalloc) {
return;
}
get_allocator_unlocked(domain, &_PyMem_Debug.mem.alloc);
alloc.ctx = &_PyMem_Debug.mem;
alloc.malloc = _PyMem_DebugMalloc;
alloc.calloc = _PyMem_DebugCalloc;
alloc.realloc = _PyMem_DebugRealloc;
alloc.free = _PyMem_DebugFree;
set_allocator_unlocked(domain, &alloc);
}
else if (domain == PYMEM_DOMAIN_OBJ) {
if (_PyObject.malloc == _PyMem_DebugMalloc) {
return;
}
get_allocator_unlocked(domain, &_PyMem_Debug.obj.alloc);
alloc.ctx = &_PyMem_Debug.obj;
alloc.malloc = _PyMem_DebugMalloc;
alloc.calloc = _PyMem_DebugCalloc;
alloc.realloc = _PyMem_DebugRealloc;
alloc.free = _PyMem_DebugFree;
set_allocator_unlocked(domain, &alloc);
}
}
static void
set_up_debug_hooks_unlocked(void)
{
set_up_debug_hooks_domain_unlocked(PYMEM_DOMAIN_RAW);
set_up_debug_hooks_domain_unlocked(PYMEM_DOMAIN_MEM);
set_up_debug_hooks_domain_unlocked(PYMEM_DOMAIN_OBJ);
}
void
PyMem_SetupDebugHooks(void)
{
if (ALLOCATORS_MUTEX == NULL) {
/* The runtime must not be completely initialized yet. */
set_up_debug_hooks_unlocked();
return;
}
PyThread_acquire_lock(ALLOCATORS_MUTEX, WAIT_LOCK);
set_up_debug_hooks_unlocked();
PyThread_release_lock(ALLOCATORS_MUTEX);
}
static void
get_allocator_unlocked(PyMemAllocatorDomain domain, PyMemAllocatorEx *allocator)
{
switch(domain)
{
case PYMEM_DOMAIN_RAW: *allocator = _PyMem_Raw; break;
case PYMEM_DOMAIN_MEM: *allocator = _PyMem; break;
case PYMEM_DOMAIN_OBJ: *allocator = _PyObject; break;
default:
/* unknown domain: set all attributes to NULL */
allocator->ctx = NULL;
allocator->malloc = NULL;
allocator->calloc = NULL;
allocator->realloc = NULL;
allocator->free = NULL;
}
}
static void
set_allocator_unlocked(PyMemAllocatorDomain domain, PyMemAllocatorEx *allocator)
{
switch(domain)
{
case PYMEM_DOMAIN_RAW: _PyMem_Raw = *allocator; break;
case PYMEM_DOMAIN_MEM: _PyMem = *allocator; break;
case PYMEM_DOMAIN_OBJ: _PyObject = *allocator; break;
/* ignore unknown domain */
}
}
void
PyMem_GetAllocator(PyMemAllocatorDomain domain, PyMemAllocatorEx *allocator)
{
if (ALLOCATORS_MUTEX == NULL) {
/* The runtime must not be completely initialized yet. */
get_allocator_unlocked(domain, allocator);
return;
}
PyThread_acquire_lock(ALLOCATORS_MUTEX, WAIT_LOCK);
get_allocator_unlocked(domain, allocator);
PyThread_release_lock(ALLOCATORS_MUTEX);
}
void
PyMem_SetAllocator(PyMemAllocatorDomain domain, PyMemAllocatorEx *allocator)
{
if (ALLOCATORS_MUTEX == NULL) {
/* The runtime must not be completely initialized yet. */
set_allocator_unlocked(domain, allocator);
return;
}
PyThread_acquire_lock(ALLOCATORS_MUTEX, WAIT_LOCK);
set_allocator_unlocked(domain, allocator);
PyThread_release_lock(ALLOCATORS_MUTEX);
}
void
PyObject_GetArenaAllocator(PyObjectArenaAllocator *allocator)
{
if (ALLOCATORS_MUTEX == NULL) {
/* The runtime must not be completely initialized yet. */
*allocator = _PyObject_Arena;
return;
}
PyThread_acquire_lock(ALLOCATORS_MUTEX, WAIT_LOCK);
*allocator = _PyObject_Arena;
PyThread_release_lock(ALLOCATORS_MUTEX);
}
void
PyObject_SetArenaAllocator(PyObjectArenaAllocator *allocator)
{
if (ALLOCATORS_MUTEX == NULL) {
/* The runtime must not be completely initialized yet. */
_PyObject_Arena = *allocator;
return;
}
PyThread_acquire_lock(ALLOCATORS_MUTEX, WAIT_LOCK);
_PyObject_Arena = *allocator;
PyThread_release_lock(ALLOCATORS_MUTEX);
}
/* Note that there is a possible, but very unlikely, race in any place
* below where we call one of the allocator functions. We access two
* fields in each case: "malloc", etc. and "ctx".
*
* It is unlikely that the allocator will be changed while one of those
* calls is happening, much less in that very narrow window.
* Furthermore, the likelihood of a race is drastically reduced by the
* fact that the allocator may not be changed after runtime init
* (except with a wrapper).
*
* With the above in mind, we currently don't worry about locking
* around these uses of the runtime-global allocators state. */
/*************************/
/* the "arena" allocator */
/*************************/
void *
_PyObject_VirtualAlloc(size_t size)
{
return _PyObject_Arena.alloc(_PyObject_Arena.ctx, size);
}
void
_PyObject_VirtualFree(void *obj, size_t size)
{
_PyObject_Arena.free(_PyObject_Arena.ctx, obj, size);
}
/***********************/
/* the "raw" allocator */
/***********************/
void *
PyMem_RawMalloc(size_t size)
{
/*
* Limit ourselves to PY_SSIZE_T_MAX bytes to prevent security holes.
* Most python internals blindly use a signed Py_ssize_t to track
* things without checking for overflows or negatives.
* As size_t is unsigned, checking for size < 0 is not required.
*/
if (size > (size_t)PY_SSIZE_T_MAX)
return NULL;
return _PyMem_Raw.malloc(_PyMem_Raw.ctx, size);
}
void *
PyMem_RawCalloc(size_t nelem, size_t elsize)
{
/* see PyMem_RawMalloc() */
if (elsize != 0 && nelem > (size_t)PY_SSIZE_T_MAX / elsize)
return NULL;
return _PyMem_Raw.calloc(_PyMem_Raw.ctx, nelem, elsize);
}
void*
PyMem_RawRealloc(void *ptr, size_t new_size)
{
/* see PyMem_RawMalloc() */
if (new_size > (size_t)PY_SSIZE_T_MAX)
return NULL;
return _PyMem_Raw.realloc(_PyMem_Raw.ctx, ptr, new_size);
}
void PyMem_RawFree(void *ptr)
{
_PyMem_Raw.free(_PyMem_Raw.ctx, ptr);
}
/***********************/
/* the "mem" allocator */
/***********************/
void *
PyMem_Malloc(size_t size)
{
/* see PyMem_RawMalloc() */
if (size > (size_t)PY_SSIZE_T_MAX)
return NULL;
OBJECT_STAT_INC_COND(allocations512, size < 512);
OBJECT_STAT_INC_COND(allocations4k, size >= 512 && size < 4094);
OBJECT_STAT_INC_COND(allocations_big, size >= 4094);
OBJECT_STAT_INC(allocations);
return _PyMem.malloc(_PyMem.ctx, size);
}
void *
PyMem_Calloc(size_t nelem, size_t elsize)
{
/* see PyMem_RawMalloc() */
if (elsize != 0 && nelem > (size_t)PY_SSIZE_T_MAX / elsize)
return NULL;
OBJECT_STAT_INC_COND(allocations512, elsize < 512);
OBJECT_STAT_INC_COND(allocations4k, elsize >= 512 && elsize < 4094);
OBJECT_STAT_INC_COND(allocations_big, elsize >= 4094);
OBJECT_STAT_INC(allocations);
return _PyMem.calloc(_PyMem.ctx, nelem, elsize);
}
void *
PyMem_Realloc(void *ptr, size_t new_size)
{
/* see PyMem_RawMalloc() */
if (new_size > (size_t)PY_SSIZE_T_MAX)
return NULL;
return _PyMem.realloc(_PyMem.ctx, ptr, new_size);
}
void
PyMem_Free(void *ptr)
{
OBJECT_STAT_INC(frees);
_PyMem.free(_PyMem.ctx, ptr);
}
/***************************/
/* pymem utility functions */
/***************************/
wchar_t*
_PyMem_RawWcsdup(const wchar_t *str)
{
assert(str != NULL);
size_t len = wcslen(str);
if (len > (size_t)PY_SSIZE_T_MAX / sizeof(wchar_t) - 1) {
return NULL;
}
size_t size = (len + 1) * sizeof(wchar_t);
wchar_t *str2 = PyMem_RawMalloc(size);
if (str2 == NULL) {
return NULL;
}
memcpy(str2, str, size);
return str2;
}
char *
_PyMem_RawStrdup(const char *str)
{
assert(str != NULL);
size_t size = strlen(str) + 1;
char *copy = PyMem_RawMalloc(size);
if (copy == NULL) {
return NULL;
}
memcpy(copy, str, size);
return copy;
}
char *
_PyMem_Strdup(const char *str)
{
assert(str != NULL);
size_t size = strlen(str) + 1;
char *copy = PyMem_Malloc(size);
if (copy == NULL) {
return NULL;
}
memcpy(copy, str, size);
return copy;
}
/**************************/
/* the "object" allocator */
/**************************/
void *
PyObject_Malloc(size_t size)
{
/* see PyMem_RawMalloc() */
if (size > (size_t)PY_SSIZE_T_MAX)
return NULL;
OBJECT_STAT_INC_COND(allocations512, size < 512);
OBJECT_STAT_INC_COND(allocations4k, size >= 512 && size < 4094);
OBJECT_STAT_INC_COND(allocations_big, size >= 4094);
OBJECT_STAT_INC(allocations);
return _PyObject.malloc(_PyObject.ctx, size);
}
void *
PyObject_Calloc(size_t nelem, size_t elsize)
{
/* see PyMem_RawMalloc() */
if (elsize != 0 && nelem > (size_t)PY_SSIZE_T_MAX / elsize)
return NULL;
OBJECT_STAT_INC_COND(allocations512, elsize < 512);
OBJECT_STAT_INC_COND(allocations4k, elsize >= 512 && elsize < 4094);
OBJECT_STAT_INC_COND(allocations_big, elsize >= 4094);
OBJECT_STAT_INC(allocations);
return _PyObject.calloc(_PyObject.ctx, nelem, elsize);
}
void *
PyObject_Realloc(void *ptr, size_t new_size)
{
/* see PyMem_RawMalloc() */
if (new_size > (size_t)PY_SSIZE_T_MAX)
return NULL;
return _PyObject.realloc(_PyObject.ctx, ptr, new_size);
}
void
PyObject_Free(void *ptr)
{
OBJECT_STAT_INC(frees);
_PyObject.free(_PyObject.ctx, ptr);
}
/* If we're using GCC, use __builtin_expect() to reduce overhead of
the valgrind checks */
#if defined(__GNUC__) && (__GNUC__ > 2) && defined(__OPTIMIZE__)
# define UNLIKELY(value) __builtin_expect((value), 0)
# define LIKELY(value) __builtin_expect((value), 1)
#else
# define UNLIKELY(value) (value)
# define LIKELY(value) (value)
#endif
#ifdef WITH_PYMALLOC
#ifdef WITH_VALGRIND
#include <valgrind/valgrind.h>
/* -1 indicates that we haven't checked that we're running on valgrind yet. */
static int running_on_valgrind = -1;
#endif
typedef struct _obmalloc_state OMState;
static inline int
has_own_state(PyInterpreterState *interp)
{
return (_Py_IsMainInterpreter(interp) ||
!(interp->feature_flags & Py_RTFLAGS_USE_MAIN_OBMALLOC) ||
_Py_IsMainInterpreterFinalizing(interp));
}
static inline OMState *
get_state(void)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
if (!has_own_state(interp)) {
interp = _PyInterpreterState_Main();
}
return &interp->obmalloc;
}
// These macros all rely on a local "state" variable.
#define usedpools (state->pools.used)
#define allarenas (state->mgmt.arenas)
#define maxarenas (state->mgmt.maxarenas)
#define unused_arena_objects (state->mgmt.unused_arena_objects)
#define usable_arenas (state->mgmt.usable_arenas)
#define nfp2lasta (state->mgmt.nfp2lasta)
#define narenas_currently_allocated (state->mgmt.narenas_currently_allocated)
#define ntimes_arena_allocated (state->mgmt.ntimes_arena_allocated)
#define narenas_highwater (state->mgmt.narenas_highwater)
#define raw_allocated_blocks (state->mgmt.raw_allocated_blocks)
Py_ssize_t
_PyInterpreterState_GetAllocatedBlocks(PyInterpreterState *interp)
{
#ifdef Py_DEBUG
assert(has_own_state(interp));
#else
if (!has_own_state(interp)) {
_Py_FatalErrorFunc(__func__,
"the interpreter doesn't have its own allocator");
}
#endif
OMState *state = &interp->obmalloc;
Py_ssize_t n = raw_allocated_blocks;
/* add up allocated blocks for used pools */
for (uint i = 0; i < maxarenas; ++i) {
/* Skip arenas which are not allocated. */
if (allarenas[i].address == 0) {
continue;
}
uintptr_t base = (uintptr_t)_Py_ALIGN_UP(allarenas[i].address, POOL_SIZE);
/* visit every pool in the arena */
assert(base <= (uintptr_t) allarenas[i].pool_address);
for (; base < (uintptr_t) allarenas[i].pool_address; base += POOL_SIZE) {
poolp p = (poolp)base;
n += p->ref.count;
}
}
return n;
}
void
_PyInterpreterState_FinalizeAllocatedBlocks(PyInterpreterState *interp)
{
if (has_own_state(interp)) {
Py_ssize_t leaked = _PyInterpreterState_GetAllocatedBlocks(interp);
assert(has_own_state(interp) || leaked == 0);
interp->runtime->obmalloc.interpreter_leaks += leaked;
}
}
static Py_ssize_t get_num_global_allocated_blocks(_PyRuntimeState *);
/* We preserve the number of blockss leaked during runtime finalization,
so they can be reported if the runtime is initialized again. */
// XXX We don't lose any information by dropping this,
// so we should consider doing so.
static Py_ssize_t last_final_leaks = 0;
void
_Py_FinalizeAllocatedBlocks(_PyRuntimeState *runtime)
{
last_final_leaks = get_num_global_allocated_blocks(runtime);
runtime->obmalloc.interpreter_leaks = 0;
}
static Py_ssize_t
get_num_global_allocated_blocks(_PyRuntimeState *runtime)
{
Py_ssize_t total = 0;
if (_PyRuntimeState_GetFinalizing(runtime) != NULL) {
PyInterpreterState *interp = _PyInterpreterState_Main();
if (interp == NULL) {
/* We are at the very end of runtime finalization.
We can't rely on finalizing->interp since that thread
state is probably already freed, so we don't worry
about it. */
assert(PyInterpreterState_Head() == NULL);
}
else {
assert(interp != NULL);
/* It is probably the last interpreter but not necessarily. */
assert(PyInterpreterState_Next(interp) == NULL);
total += _PyInterpreterState_GetAllocatedBlocks(interp);
}
}
else {
HEAD_LOCK(runtime);
PyInterpreterState *interp = PyInterpreterState_Head();
assert(interp != NULL);
#ifdef Py_DEBUG
int got_main = 0;
#endif
for (; interp != NULL; interp = PyInterpreterState_Next(interp)) {
#ifdef Py_DEBUG
if (_Py_IsMainInterpreter(interp)) {
assert(!got_main);
got_main = 1;
assert(has_own_state(interp));
}
#endif
if (has_own_state(interp)) {
total += _PyInterpreterState_GetAllocatedBlocks(interp);
}
}
HEAD_UNLOCK(runtime);
#ifdef Py_DEBUG
assert(got_main);
#endif
}
total += runtime->obmalloc.interpreter_leaks;
total += last_final_leaks;
return total;
}
Py_ssize_t
_Py_GetGlobalAllocatedBlocks(void)
{
return get_num_global_allocated_blocks(&_PyRuntime);
}
#if WITH_PYMALLOC_RADIX_TREE
/*==========================================================================*/
/* radix tree for tracking arena usage. */
#define arena_map_root (state->usage.arena_map_root)
#ifdef USE_INTERIOR_NODES
#define arena_map_mid_count (state->usage.arena_map_mid_count)
#define arena_map_bot_count (state->usage.arena_map_bot_count)
#endif
/* Return a pointer to a bottom tree node, return NULL if it doesn't exist or
* it cannot be created */
static inline Py_ALWAYS_INLINE arena_map_bot_t *
arena_map_get(OMState *state, pymem_block *p, int create)
{
#ifdef USE_INTERIOR_NODES
/* sanity check that IGNORE_BITS is correct */
assert(HIGH_BITS(p) == HIGH_BITS(&arena_map_root));
int i1 = MAP_TOP_INDEX(p);
if (arena_map_root.ptrs[i1] == NULL) {
if (!create) {
return NULL;
}
arena_map_mid_t *n = PyMem_RawCalloc(1, sizeof(arena_map_mid_t));
if (n == NULL) {
return NULL;
}
arena_map_root.ptrs[i1] = n;
arena_map_mid_count++;
}
int i2 = MAP_MID_INDEX(p);
if (arena_map_root.ptrs[i1]->ptrs[i2] == NULL) {
if (!create) {
return NULL;
}
arena_map_bot_t *n = PyMem_RawCalloc(1, sizeof(arena_map_bot_t));
if (n == NULL) {
return NULL;
}
arena_map_root.ptrs[i1]->ptrs[i2] = n;
arena_map_bot_count++;
}
return arena_map_root.ptrs[i1]->ptrs[i2];
#else
return &arena_map_root;
#endif
}
/* The radix tree only tracks arenas. So, for 16 MiB arenas, we throw
* away 24 bits of the address. That reduces the space requirement of
* the tree compared to similar radix tree page-map schemes. In
* exchange for slashing the space requirement, it needs more
* computation to check an address.
*
* Tracking coverage is done by "ideal" arena address. It is easier to
* explain in decimal so let's say that the arena size is 100 bytes.
* Then, ideal addresses are 100, 200, 300, etc. For checking if a
* pointer address is inside an actual arena, we have to check two ideal
* arena addresses. E.g. if pointer is 357, we need to check 200 and
* 300. In the rare case that an arena is aligned in the ideal way
* (e.g. base address of arena is 200) then we only have to check one
* ideal address.
*
* The tree nodes for 200 and 300 both store the address of arena.
* There are two cases: the arena starts at a lower ideal arena and
* extends to this one, or the arena starts in this arena and extends to
* the next ideal arena. The tail_lo and tail_hi members correspond to
* these two cases.
*/
/* mark or unmark addresses covered by arena */
static int
arena_map_mark_used(OMState *state, uintptr_t arena_base, int is_used)
{
/* sanity check that IGNORE_BITS is correct */
assert(HIGH_BITS(arena_base) == HIGH_BITS(&arena_map_root));
arena_map_bot_t *n_hi = arena_map_get(
state, (pymem_block *)arena_base, is_used);
if (n_hi == NULL) {
assert(is_used); /* otherwise node should already exist */
return 0; /* failed to allocate space for node */
}
int i3 = MAP_BOT_INDEX((pymem_block *)arena_base);
int32_t tail = (int32_t)(arena_base & ARENA_SIZE_MASK);
if (tail == 0) {
/* is ideal arena address */
n_hi->arenas[i3].tail_hi = is_used ? -1 : 0;
}
else {
/* arena_base address is not ideal (aligned to arena size) and
* so it potentially covers two MAP_BOT nodes. Get the MAP_BOT node
* for the next arena. Note that it might be in different MAP_TOP
* and MAP_MID nodes as well so we need to call arena_map_get()
* again (do the full tree traversal).
*/
n_hi->arenas[i3].tail_hi = is_used ? tail : 0;
uintptr_t arena_base_next = arena_base + ARENA_SIZE;
/* If arena_base is a legit arena address, so is arena_base_next - 1
* (last address in arena). If arena_base_next overflows then it
* must overflow to 0. However, that would mean arena_base was
* "ideal" and we should not be in this case. */
assert(arena_base < arena_base_next);
arena_map_bot_t *n_lo = arena_map_get(
state, (pymem_block *)arena_base_next, is_used);
if (n_lo == NULL) {
assert(is_used); /* otherwise should already exist */
n_hi->arenas[i3].tail_hi = 0;
return 0; /* failed to allocate space for node */
}
int i3_next = MAP_BOT_INDEX(arena_base_next);
n_lo->arenas[i3_next].tail_lo = is_used ? tail : 0;
}
return 1;
}
/* Return true if 'p' is a pointer inside an obmalloc arena.
* _PyObject_Free() calls this so it needs to be very fast. */
static int
arena_map_is_used(OMState *state, pymem_block *p)
{
arena_map_bot_t *n = arena_map_get(state, p, 0);
if (n == NULL) {
return 0;
}
int i3 = MAP_BOT_INDEX(p);
/* ARENA_BITS must be < 32 so that the tail is a non-negative int32_t. */
int32_t hi = n->arenas[i3].tail_hi;
int32_t lo = n->arenas[i3].tail_lo;
int32_t tail = (int32_t)(AS_UINT(p) & ARENA_SIZE_MASK);
return (tail < lo) || (tail >= hi && hi != 0);
}
/* end of radix tree logic */
/*==========================================================================*/
#endif /* WITH_PYMALLOC_RADIX_TREE */
/* Allocate a new arena. If we run out of memory, return NULL. Else
* allocate a new arena, and return the address of an arena_object
* describing the new arena. It's expected that the caller will set
* `usable_arenas` to the return value.
*/
static struct arena_object*
new_arena(OMState *state)
{
struct arena_object* arenaobj;
uint excess; /* number of bytes above pool alignment */
void *address;
int debug_stats = _PyRuntime.obmalloc.dump_debug_stats;
if (debug_stats == -1) {
const char *opt = Py_GETENV("PYTHONMALLOCSTATS");
debug_stats = (opt != NULL && *opt != '\0');
_PyRuntime.obmalloc.dump_debug_stats = debug_stats;
}
if (debug_stats) {
_PyObject_DebugMallocStats(stderr);
}
if (unused_arena_objects == NULL) {
uint i;
uint numarenas;
size_t nbytes;
/* Double the number of arena objects on each allocation.
* Note that it's possible for `numarenas` to overflow.
*/
numarenas = maxarenas ? maxarenas << 1 : INITIAL_ARENA_OBJECTS;
if (numarenas <= maxarenas)
return NULL; /* overflow */
#if SIZEOF_SIZE_T <= SIZEOF_INT
if (numarenas > SIZE_MAX / sizeof(*allarenas))
return NULL; /* overflow */
#endif
nbytes = numarenas * sizeof(*allarenas);
arenaobj = (struct arena_object *)PyMem_RawRealloc(allarenas, nbytes);
if (arenaobj == NULL)
return NULL;
allarenas = arenaobj;
/* We might need to fix pointers that were copied. However,
* new_arena only gets called when all the pages in the
* previous arenas are full. Thus, there are *no* pointers
* into the old array. Thus, we don't have to worry about
* invalid pointers. Just to be sure, some asserts:
*/
assert(usable_arenas == NULL);
assert(unused_arena_objects == NULL);
/* Put the new arenas on the unused_arena_objects list. */
for (i = maxarenas; i < numarenas; ++i) {
allarenas[i].address = 0; /* mark as unassociated */
allarenas[i].nextarena = i < numarenas - 1 ?
&allarenas[i+1] : NULL;
}
/* Update globals. */
unused_arena_objects = &allarenas[maxarenas];
maxarenas = numarenas;
}
/* Take the next available arena object off the head of the list. */
assert(unused_arena_objects != NULL);
arenaobj = unused_arena_objects;
unused_arena_objects = arenaobj->nextarena;
assert(arenaobj->address == 0);
address = _PyObject_Arena.alloc(_PyObject_Arena.ctx, ARENA_SIZE);
#if WITH_PYMALLOC_RADIX_TREE
if (address != NULL) {
if (!arena_map_mark_used(state, (uintptr_t)address, 1)) {
/* marking arena in radix tree failed, abort */
_PyObject_Arena.free(_PyObject_Arena.ctx, address, ARENA_SIZE);
address = NULL;
}
}
#endif
if (address == NULL) {
/* The allocation failed: return NULL after putting the
* arenaobj back.
*/
arenaobj->nextarena = unused_arena_objects;
unused_arena_objects = arenaobj;
return NULL;
}
arenaobj->address = (uintptr_t)address;
++narenas_currently_allocated;
++ntimes_arena_allocated;
if (narenas_currently_allocated > narenas_highwater)
narenas_highwater = narenas_currently_allocated;
arenaobj->freepools = NULL;
/* pool_address <- first pool-aligned address in the arena
nfreepools <- number of whole pools that fit after alignment */
arenaobj->pool_address = (pymem_block*)arenaobj->address;
arenaobj->nfreepools = MAX_POOLS_IN_ARENA;
excess = (uint)(arenaobj->address & POOL_SIZE_MASK);
if (excess != 0) {
--arenaobj->nfreepools;
arenaobj->pool_address += POOL_SIZE - excess;
}
arenaobj->ntotalpools = arenaobj->nfreepools;
return arenaobj;
}
#if WITH_PYMALLOC_RADIX_TREE
/* Return true if and only if P is an address that was allocated by
pymalloc. When the radix tree is used, 'poolp' is unused.
*/
static bool
address_in_range(OMState *state, void *p, poolp Py_UNUSED(pool))
{
return arena_map_is_used(state, p);
}
#else
/*
address_in_range(P, POOL)
Return true if and only if P is an address that was allocated by pymalloc.
POOL must be the pool address associated with P, i.e., POOL = POOL_ADDR(P)
(the caller is asked to compute this because the macro expands POOL more than
once, and for efficiency it's best for the caller to assign POOL_ADDR(P) to a
variable and pass the latter to the macro; because address_in_range is
called on every alloc/realloc/free, micro-efficiency is important here).
Tricky: Let B be the arena base address associated with the pool, B =
arenas[(POOL)->arenaindex].address. Then P belongs to the arena if and only if
B <= P < B + ARENA_SIZE
Subtracting B throughout, this is true iff
0 <= P-B < ARENA_SIZE
By using unsigned arithmetic, the "0 <=" half of the test can be skipped.
Obscure: A PyMem "free memory" function can call the pymalloc free or realloc
before the first arena has been allocated. `arenas` is still NULL in that
case. We're relying on that maxarenas is also 0 in that case, so that
(POOL)->arenaindex < maxarenas must be false, saving us from trying to index
into a NULL arenas.
Details: given P and POOL, the arena_object corresponding to P is AO =
arenas[(POOL)->arenaindex]. Suppose obmalloc controls P. Then (barring wild
stores, etc), POOL is the correct address of P's pool, AO.address is the
correct base address of the pool's arena, and P must be within ARENA_SIZE of
AO.address. In addition, AO.address is not 0 (no arena can start at address 0
(NULL)). Therefore address_in_range correctly reports that obmalloc
controls P.
Now suppose obmalloc does not control P (e.g., P was obtained via a direct
call to the system malloc() or realloc()). (POOL)->arenaindex may be anything
in this case -- it may even be uninitialized trash. If the trash arenaindex
is >= maxarenas, the macro correctly concludes at once that obmalloc doesn't
control P.
Else arenaindex is < maxarena, and AO is read up. If AO corresponds to an
allocated arena, obmalloc controls all the memory in slice AO.address :
AO.address+ARENA_SIZE. By case assumption, P is not controlled by obmalloc,
so P doesn't lie in that slice, so the macro correctly reports that P is not
controlled by obmalloc.
Finally, if P is not controlled by obmalloc and AO corresponds to an unused
arena_object (one not currently associated with an allocated arena),
AO.address is 0, and the second test in the macro reduces to:
P < ARENA_SIZE
If P >= ARENA_SIZE (extremely likely), the macro again correctly concludes
that P is not controlled by obmalloc. However, if P < ARENA_SIZE, this part
of the test still passes, and the third clause (AO.address != 0) is necessary
to get the correct result: AO.address is 0 in this case, so the macro
correctly reports that P is not controlled by obmalloc (despite that P lies in
slice AO.address : AO.address + ARENA_SIZE).
Note: The third (AO.address != 0) clause was added in Python 2.5. Before
2.5, arenas were never free()'ed, and an arenaindex < maxarena always
corresponded to a currently-allocated arena, so the "P is not controlled by
obmalloc, AO corresponds to an unused arena_object, and P < ARENA_SIZE" case
was impossible.
Note that the logic is excruciating, and reading up possibly uninitialized
memory when P is not controlled by obmalloc (to get at (POOL)->arenaindex)
creates problems for some memory debuggers. The overwhelming advantage is
that this test determines whether an arbitrary address is controlled by
obmalloc in a small constant time, independent of the number of arenas
obmalloc controls. Since this test is needed at every entry point, it's
extremely desirable that it be this fast.
*/
static bool _Py_NO_SANITIZE_ADDRESS
_Py_NO_SANITIZE_THREAD
_Py_NO_SANITIZE_MEMORY
address_in_range(OMState *state, void *p, poolp pool)
{
// Since address_in_range may be reading from memory which was not allocated
// by Python, it is important that pool->arenaindex is read only once, as
// another thread may be concurrently modifying the value without holding
// the GIL. The following dance forces the compiler to read pool->arenaindex
// only once.
uint arenaindex = *((volatile uint *)&pool->arenaindex);
return arenaindex < maxarenas &&
(uintptr_t)p - allarenas[arenaindex].address < ARENA_SIZE &&
allarenas[arenaindex].address != 0;
}
#endif /* !WITH_PYMALLOC_RADIX_TREE */
/*==========================================================================*/
// Called when freelist is exhausted. Extend the freelist if there is
// space for a block. Otherwise, remove this pool from usedpools.
static void
pymalloc_pool_extend(poolp pool, uint size)
{
if (UNLIKELY(pool->nextoffset <= pool->maxnextoffset)) {
/* There is room for another block. */
pool->freeblock = (pymem_block*)pool + pool->nextoffset;
pool->nextoffset += INDEX2SIZE(size);
*(pymem_block **)(pool->freeblock) = NULL;
return;
}
/* Pool is full, unlink from used pools. */
poolp next;
next = pool->nextpool;
pool = pool->prevpool;
next->prevpool = pool;
pool->nextpool = next;
}
/* called when pymalloc_alloc can not allocate a block from usedpool.
* This function takes new pool and allocate a block from it.
*/
static void*
allocate_from_new_pool(OMState *state, uint size)
{
/* There isn't a pool of the right size class immediately
* available: use a free pool.
*/
if (UNLIKELY(usable_arenas == NULL)) {
/* No arena has a free pool: allocate a new arena. */
#ifdef WITH_MEMORY_LIMITS
if (narenas_currently_allocated >= MAX_ARENAS) {
return NULL;
}
#endif
usable_arenas = new_arena(state);
if (usable_arenas == NULL) {
return NULL;
}
usable_arenas->nextarena = usable_arenas->prevarena = NULL;
assert(nfp2lasta[usable_arenas->nfreepools] == NULL);
nfp2lasta[usable_arenas->nfreepools] = usable_arenas;
}
assert(usable_arenas->address != 0);
/* This arena already had the smallest nfreepools value, so decreasing
* nfreepools doesn't change that, and we don't need to rearrange the
* usable_arenas list. However, if the arena becomes wholly allocated,
* we need to remove its arena_object from usable_arenas.
*/
assert(usable_arenas->nfreepools > 0);
if (nfp2lasta[usable_arenas->nfreepools] == usable_arenas) {
/* It's the last of this size, so there won't be any. */
nfp2lasta[usable_arenas->nfreepools] = NULL;
}
/* If any free pools will remain, it will be the new smallest. */
if (usable_arenas->nfreepools > 1) {
assert(nfp2lasta[usable_arenas->nfreepools - 1] == NULL);
nfp2lasta[usable_arenas->nfreepools - 1] = usable_arenas;
}
/* Try to get a cached free pool. */
poolp pool = usable_arenas->freepools;
if (LIKELY(pool != NULL)) {
/* Unlink from cached pools. */
usable_arenas->freepools = pool->nextpool;
usable_arenas->nfreepools--;
if (UNLIKELY(usable_arenas->nfreepools == 0)) {
/* Wholly allocated: remove. */
assert(usable_arenas->freepools == NULL);
assert(usable_arenas->nextarena == NULL ||
usable_arenas->nextarena->prevarena ==
usable_arenas);
usable_arenas = usable_arenas->nextarena;
if (usable_arenas != NULL) {
usable_arenas->prevarena = NULL;
assert(usable_arenas->address != 0);
}
}
else {
/* nfreepools > 0: it must be that freepools
* isn't NULL, or that we haven't yet carved
* off all the arena's pools for the first
* time.
*/
assert(usable_arenas->freepools != NULL ||
usable_arenas->pool_address <=
(pymem_block*)usable_arenas->address +
ARENA_SIZE - POOL_SIZE);
}
}
else {
/* Carve off a new pool. */
assert(usable_arenas->nfreepools > 0);
assert(usable_arenas->freepools == NULL);
pool = (poolp)usable_arenas->pool_address;
assert((pymem_block*)pool <= (pymem_block*)usable_arenas->address +
ARENA_SIZE - POOL_SIZE);
pool->arenaindex = (uint)(usable_arenas - allarenas);
assert(&allarenas[pool->arenaindex] == usable_arenas);
pool->szidx = DUMMY_SIZE_IDX;
usable_arenas->pool_address += POOL_SIZE;
--usable_arenas->nfreepools;
if (usable_arenas->nfreepools == 0) {
assert(usable_arenas->nextarena == NULL ||
usable_arenas->nextarena->prevarena ==
usable_arenas);
/* Unlink the arena: it is completely allocated. */
usable_arenas = usable_arenas->nextarena;
if (usable_arenas != NULL) {
usable_arenas->prevarena = NULL;
assert(usable_arenas->address != 0);
}
}
}
/* Frontlink to used pools. */
pymem_block *bp;
poolp next = usedpools[size + size]; /* == prev */
pool->nextpool = next;
pool->prevpool = next;
next->nextpool = pool;
next->prevpool = pool;
pool->ref.count = 1;
if (pool->szidx == size) {
/* Luckily, this pool last contained blocks
* of the same size class, so its header
* and free list are already initialized.
*/
bp = pool->freeblock;
assert(bp != NULL);
pool->freeblock = *(pymem_block **)bp;
return bp;
}
/*
* Initialize the pool header, set up the free list to
* contain just the second block, and return the first
* block.
*/
pool->szidx = size;
size = INDEX2SIZE(size);
bp = (pymem_block *)pool + POOL_OVERHEAD;
pool->nextoffset = POOL_OVERHEAD + (size << 1);
pool->maxnextoffset = POOL_SIZE - size;
pool->freeblock = bp + size;
*(pymem_block **)(pool->freeblock) = NULL;
return bp;
}
/* pymalloc allocator
Return a pointer to newly allocated memory if pymalloc allocated memory.
Return NULL if pymalloc failed to allocate the memory block: on bigger
requests, on error in the code below (as a last chance to serve the request)
or when the max memory limit has been reached.
*/
static inline void*
pymalloc_alloc(OMState *state, void *Py_UNUSED(ctx), size_t nbytes)
{
#ifdef WITH_VALGRIND
if (UNLIKELY(running_on_valgrind == -1)) {
running_on_valgrind = RUNNING_ON_VALGRIND;
}
if (UNLIKELY(running_on_valgrind)) {
return NULL;
}
#endif
if (UNLIKELY(nbytes == 0)) {
return NULL;
}
if (UNLIKELY(nbytes > SMALL_REQUEST_THRESHOLD)) {
return NULL;
}
uint size = (uint)(nbytes - 1) >> ALIGNMENT_SHIFT;
poolp pool = usedpools[size + size];
pymem_block *bp;
if (LIKELY(pool != pool->nextpool)) {
/*
* There is a used pool for this size class.
* Pick up the head block of its free list.
*/
++pool->ref.count;
bp = pool->freeblock;
assert(bp != NULL);
if (UNLIKELY((pool->freeblock = *(pymem_block **)bp) == NULL)) {
// Reached the end of the free list, try to extend it.
pymalloc_pool_extend(pool, size);
}
}
else {
/* There isn't a pool of the right size class immediately
* available: use a free pool.
*/
bp = allocate_from_new_pool(state, size);
}
return (void *)bp;
}
void *
_PyObject_Malloc(void *ctx, size_t nbytes)
{
OMState *state = get_state();
void* ptr = pymalloc_alloc(state, ctx, nbytes);
if (LIKELY(ptr != NULL)) {
return ptr;
}
ptr = PyMem_RawMalloc(nbytes);
if (ptr != NULL) {
raw_allocated_blocks++;
}
return ptr;
}
void *
_PyObject_Calloc(void *ctx, size_t nelem, size_t elsize)
{
assert(elsize == 0 || nelem <= (size_t)PY_SSIZE_T_MAX / elsize);
size_t nbytes = nelem * elsize;
OMState *state = get_state();
void* ptr = pymalloc_alloc(state, ctx, nbytes);
if (LIKELY(ptr != NULL)) {
memset(ptr, 0, nbytes);
return ptr;
}
ptr = PyMem_RawCalloc(nelem, elsize);
if (ptr != NULL) {
raw_allocated_blocks++;
}
return ptr;
}
static void
insert_to_usedpool(OMState *state, poolp pool)
{
assert(pool->ref.count > 0); /* else the pool is empty */
uint size = pool->szidx;
poolp next = usedpools[size + size];
poolp prev = next->prevpool;
/* insert pool before next: prev <-> pool <-> next */
pool->nextpool = next;
pool->prevpool = prev;
next->prevpool = pool;
prev->nextpool = pool;
}
static void
insert_to_freepool(OMState *state, poolp pool)
{
poolp next = pool->nextpool;
poolp prev = pool->prevpool;
next->prevpool = prev;
prev->nextpool = next;
/* Link the pool to freepools. This is a singly-linked
* list, and pool->prevpool isn't used there.
*/
struct arena_object *ao = &allarenas[pool->arenaindex];
pool->nextpool = ao->freepools;
ao->freepools = pool;
uint nf = ao->nfreepools;
/* If this is the rightmost arena with this number of free pools,
* nfp2lasta[nf] needs to change. Caution: if nf is 0, there
* are no arenas in usable_arenas with that value.
*/
struct arena_object* lastnf = nfp2lasta[nf];
assert((nf == 0 && lastnf == NULL) ||
(nf > 0 &&
lastnf != NULL &&
lastnf->nfreepools == nf &&
(lastnf->nextarena == NULL ||
nf < lastnf->nextarena->nfreepools)));
if (lastnf == ao) { /* it is the rightmost */
struct arena_object* p = ao->prevarena;
nfp2lasta[nf] = (p != NULL && p->nfreepools == nf) ? p : NULL;
}
ao->nfreepools = ++nf;
/* All the rest is arena management. We just freed
* a pool, and there are 4 cases for arena mgmt:
* 1. If all the pools are free, return the arena to
* the system free(). Except if this is the last
* arena in the list, keep it to avoid thrashing:
* keeping one wholly free arena in the list avoids
* pathological cases where a simple loop would
* otherwise provoke needing to allocate and free an
* arena on every iteration. See bpo-37257.
* 2. If this is the only free pool in the arena,
* add the arena back to the `usable_arenas` list.
* 3. If the "next" arena has a smaller count of free
* pools, we have to "slide this arena right" to
* restore that usable_arenas is sorted in order of
* nfreepools.
* 4. Else there's nothing more to do.
*/
if (nf == ao->ntotalpools && ao->nextarena != NULL) {
/* Case 1. First unlink ao from usable_arenas.
*/
assert(ao->prevarena == NULL ||
ao->prevarena->address != 0);
assert(ao ->nextarena == NULL ||
ao->nextarena->address != 0);
/* Fix the pointer in the prevarena, or the
* usable_arenas pointer.
*/
if (ao->prevarena == NULL) {
usable_arenas = ao->nextarena;
assert(usable_arenas == NULL ||
usable_arenas->address != 0);
}
else {
assert(ao->prevarena->nextarena == ao);
ao->prevarena->nextarena =
ao->nextarena;
}
/* Fix the pointer in the nextarena. */
if (ao->nextarena != NULL) {
assert(ao->nextarena->prevarena == ao);
ao->nextarena->prevarena =
ao->prevarena;
}
/* Record that this arena_object slot is
* available to be reused.
*/
ao->nextarena = unused_arena_objects;
unused_arena_objects = ao;
#if WITH_PYMALLOC_RADIX_TREE
/* mark arena region as not under control of obmalloc */
arena_map_mark_used(state, ao->address, 0);
#endif
/* Free the entire arena. */
_PyObject_Arena.free(_PyObject_Arena.ctx,
(void *)ao->address, ARENA_SIZE);
ao->address = 0; /* mark unassociated */
--narenas_currently_allocated;
return;
}
if (nf == 1) {
/* Case 2. Put ao at the head of
* usable_arenas. Note that because
* ao->nfreepools was 0 before, ao isn't
* currently on the usable_arenas list.
*/
ao->nextarena = usable_arenas;
ao->prevarena = NULL;
if (usable_arenas)
usable_arenas->prevarena = ao;
usable_arenas = ao;
assert(usable_arenas->address != 0);
if (nfp2lasta[1] == NULL) {
nfp2lasta[1] = ao;
}
return;
}
/* If this arena is now out of order, we need to keep
* the list sorted. The list is kept sorted so that
* the "most full" arenas are used first, which allows
* the nearly empty arenas to be completely freed. In
* a few un-scientific tests, it seems like this
* approach allowed a lot more memory to be freed.
*/
/* If this is the only arena with nf, record that. */
if (nfp2lasta[nf] == NULL) {
nfp2lasta[nf] = ao;
} /* else the rightmost with nf doesn't change */
/* If this was the rightmost of the old size, it remains in place. */
if (ao == lastnf) {
/* Case 4. Nothing to do. */
return;
}
/* If ao were the only arena in the list, the last block would have
* gotten us out.
*/
assert(ao->nextarena != NULL);
/* Case 3: We have to move the arena towards the end of the list,
* because it has more free pools than the arena to its right. It needs
* to move to follow lastnf.
* First unlink ao from usable_arenas.
*/
if (ao->prevarena != NULL) {
/* ao isn't at the head of the list */
assert(ao->prevarena->nextarena == ao);
ao->prevarena->nextarena = ao->nextarena;
}
else {
/* ao is at the head of the list */
assert(usable_arenas == ao);
usable_arenas = ao->nextarena;
}
ao->nextarena->prevarena = ao->prevarena;
/* And insert after lastnf. */
ao->prevarena = lastnf;
ao->nextarena = lastnf->nextarena;
if (ao->nextarena != NULL) {
ao->nextarena->prevarena = ao;
}
lastnf->nextarena = ao;
/* Verify that the swaps worked. */
assert(ao->nextarena == NULL || nf <= ao->nextarena->nfreepools);
assert(ao->prevarena == NULL || nf > ao->prevarena->nfreepools);
assert(ao->nextarena == NULL || ao->nextarena->prevarena == ao);
assert((usable_arenas == ao && ao->prevarena == NULL)
|| ao->prevarena->nextarena == ao);
}
/* Free a memory block allocated by pymalloc_alloc().
Return 1 if it was freed.
Return 0 if the block was not allocated by pymalloc_alloc(). */
static inline int
pymalloc_free(OMState *state, void *Py_UNUSED(ctx), void *p)
{
assert(p != NULL);
#ifdef WITH_VALGRIND
if (UNLIKELY(running_on_valgrind > 0)) {
return 0;
}
#endif
poolp pool = POOL_ADDR(p);
if (UNLIKELY(!address_in_range(state, p, pool))) {
return 0;
}
/* We allocated this address. */
/* Link p to the start of the pool's freeblock list. Since
* the pool had at least the p block outstanding, the pool
* wasn't empty (so it's already in a usedpools[] list, or
* was full and is in no list -- it's not in the freeblocks
* list in any case).
*/
assert(pool->ref.count > 0); /* else it was empty */
pymem_block *lastfree = pool->freeblock;
*(pymem_block **)p = lastfree;
pool->freeblock = (pymem_block *)p;
pool->ref.count--;
if (UNLIKELY(lastfree == NULL)) {
/* Pool was full, so doesn't currently live in any list:
* link it to the front of the appropriate usedpools[] list.
* This mimics LRU pool usage for new allocations and
* targets optimal filling when several pools contain
* blocks of the same size class.
*/
insert_to_usedpool(state, pool);
return 1;
}
/* freeblock wasn't NULL, so the pool wasn't full,
* and the pool is in a usedpools[] list.
*/
if (LIKELY(pool->ref.count != 0)) {
/* pool isn't empty: leave it in usedpools */
return 1;
}
/* Pool is now empty: unlink from usedpools, and
* link to the front of freepools. This ensures that
* previously freed pools will be allocated later
* (being not referenced, they are perhaps paged out).
*/
insert_to_freepool(state, pool);
return 1;
}
void
_PyObject_Free(void *ctx, void *p)
{
/* PyObject_Free(NULL) has no effect */
if (p == NULL) {
return;
}
OMState *state = get_state();
if (UNLIKELY(!pymalloc_free(state, ctx, p))) {
/* pymalloc didn't allocate this address */
PyMem_RawFree(p);
raw_allocated_blocks--;
}
}
/* pymalloc realloc.
If nbytes==0, then as the Python docs promise, we do not treat this like
free(p), and return a non-NULL result.
Return 1 if pymalloc reallocated memory and wrote the new pointer into
newptr_p.
Return 0 if pymalloc didn't allocated p. */
static int
pymalloc_realloc(OMState *state, void *ctx,
void **newptr_p, void *p, size_t nbytes)
{
void *bp;
poolp pool;
size_t size;
assert(p != NULL);
#ifdef WITH_VALGRIND
/* Treat running_on_valgrind == -1 the same as 0 */
if (UNLIKELY(running_on_valgrind > 0)) {
return 0;
}
#endif
pool = POOL_ADDR(p);
if (!address_in_range(state, p, pool)) {
/* pymalloc is not managing this block.
If nbytes <= SMALL_REQUEST_THRESHOLD, it's tempting to try to take
over this block. However, if we do, we need to copy the valid data
from the C-managed block to one of our blocks, and there's no
portable way to know how much of the memory space starting at p is
valid.
As bug 1185883 pointed out the hard way, it's possible that the
C-managed block is "at the end" of allocated VM space, so that a
memory fault can occur if we try to copy nbytes bytes starting at p.
Instead we punt: let C continue to manage this block. */
return 0;
}
/* pymalloc is in charge of this block */
size = INDEX2SIZE(pool->szidx);
if (nbytes <= size) {
/* The block is staying the same or shrinking.
If it's shrinking, there's a tradeoff: it costs cycles to copy the
block to a smaller size class, but it wastes memory not to copy it.
The compromise here is to copy on shrink only if at least 25% of
size can be shaved off. */
if (4 * nbytes > 3 * size) {
/* It's the same, or shrinking and new/old > 3/4. */
*newptr_p = p;
return 1;
}
size = nbytes;
}
bp = _PyObject_Malloc(ctx, nbytes);
if (bp != NULL) {
memcpy(bp, p, size);
_PyObject_Free(ctx, p);
}
*newptr_p = bp;
return 1;
}
void *
_PyObject_Realloc(void *ctx, void *ptr, size_t nbytes)
{
void *ptr2;
if (ptr == NULL) {
return _PyObject_Malloc(ctx, nbytes);
}
OMState *state = get_state();
if (pymalloc_realloc(state, ctx, &ptr2, ptr, nbytes)) {
return ptr2;
}
return PyMem_RawRealloc(ptr, nbytes);
}
#else /* ! WITH_PYMALLOC */
/*==========================================================================*/
/* pymalloc not enabled: Redirect the entry points to malloc. These will
* only be used by extensions that are compiled with pymalloc enabled. */
Py_ssize_t
_PyInterpreterState_GetAllocatedBlocks(PyInterpreterState *Py_UNUSED(interp))
{
return 0;
}
Py_ssize_t
_Py_GetGlobalAllocatedBlocks(void)
{
return 0;
}
void
_PyInterpreterState_FinalizeAllocatedBlocks(PyInterpreterState *Py_UNUSED(interp))
{
return;
}
void
_Py_FinalizeAllocatedBlocks(_PyRuntimeState *Py_UNUSED(runtime))
{
return;
}
#endif /* WITH_PYMALLOC */
/*==========================================================================*/
/* A x-platform debugging allocator. This doesn't manage memory directly,
* it wraps a real allocator, adding extra debugging info to the memory blocks.
*/
/* Uncomment this define to add the "serialno" field */
/* #define PYMEM_DEBUG_SERIALNO */
#ifdef PYMEM_DEBUG_SERIALNO
static size_t serialno = 0; /* incremented on each debug {m,re}alloc */
/* serialno is always incremented via calling this routine. The point is
* to supply a single place to set a breakpoint.
*/
static void
bumpserialno(void)
{
++serialno;
}
#endif
#define SST SIZEOF_SIZE_T
#ifdef PYMEM_DEBUG_SERIALNO
# define PYMEM_DEBUG_EXTRA_BYTES 4 * SST
#else
# define PYMEM_DEBUG_EXTRA_BYTES 3 * SST
#endif
/* Read sizeof(size_t) bytes at p as a big-endian size_t. */
static size_t
read_size_t(const void *p)
{
const uint8_t *q = (const uint8_t *)p;
size_t result = *q++;
int i;
for (i = SST; --i > 0; ++q)
result = (result << 8) | *q;
return result;
}
/* Write n as a big-endian size_t, MSB at address p, LSB at
* p + sizeof(size_t) - 1.
*/
static void
write_size_t(void *p, size_t n)
{
uint8_t *q = (uint8_t *)p + SST - 1;
int i;
for (i = SST; --i >= 0; --q) {
*q = (uint8_t)(n & 0xff);
n >>= 8;
}
}
/* Let S = sizeof(size_t). The debug malloc asks for 4 * S extra bytes and
fills them with useful stuff, here calling the underlying malloc's result p:
p[0: S]
Number of bytes originally asked for. This is a size_t, big-endian (easier
to read in a memory dump).
p[S]
API ID. See PEP 445. This is a character, but seems undocumented.
p[S+1: 2*S]
Copies of PYMEM_FORBIDDENBYTE. Used to catch under- writes and reads.
p[2*S: 2*S+n]
The requested memory, filled with copies of PYMEM_CLEANBYTE.
Used to catch reference to uninitialized memory.
&p[2*S] is returned. Note that this is 8-byte aligned if pymalloc
handled the request itself.
p[2*S+n: 2*S+n+S]
Copies of PYMEM_FORBIDDENBYTE. Used to catch over- writes and reads.
p[2*S+n+S: 2*S+n+2*S]
A serial number, incremented by 1 on each call to _PyMem_DebugMalloc
and _PyMem_DebugRealloc.
This is a big-endian size_t.
If "bad memory" is detected later, the serial number gives an
excellent way to set a breakpoint on the next run, to capture the
instant at which this block was passed out.
If PYMEM_DEBUG_SERIALNO is not defined (default), the debug malloc only asks
for 3 * S extra bytes, and omits the last serialno field.
*/
static void *
_PyMem_DebugRawAlloc(int use_calloc, void *ctx, size_t nbytes)
{
debug_alloc_api_t *api = (debug_alloc_api_t *)ctx;
uint8_t *p; /* base address of malloc'ed pad block */
uint8_t *data; /* p + 2*SST == pointer to data bytes */
uint8_t *tail; /* data + nbytes == pointer to tail pad bytes */
size_t total; /* nbytes + PYMEM_DEBUG_EXTRA_BYTES */
if (nbytes > (size_t)PY_SSIZE_T_MAX - PYMEM_DEBUG_EXTRA_BYTES) {
/* integer overflow: can't represent total as a Py_ssize_t */
return NULL;
}
total = nbytes + PYMEM_DEBUG_EXTRA_BYTES;
/* Layout: [SSSS IFFF CCCC...CCCC FFFF NNNN]
^--- p ^--- data ^--- tail
S: nbytes stored as size_t
I: API identifier (1 byte)
F: Forbidden bytes (size_t - 1 bytes before, size_t bytes after)
C: Clean bytes used later to store actual data
N: Serial number stored as size_t
If PYMEM_DEBUG_SERIALNO is not defined (default), the last NNNN field
is omitted. */
if (use_calloc) {
p = (uint8_t *)api->alloc.calloc(api->alloc.ctx, 1, total);
}
else {
p = (uint8_t *)api->alloc.malloc(api->alloc.ctx, total);
}
if (p == NULL) {
return NULL;
}
data = p + 2*SST;
#ifdef PYMEM_DEBUG_SERIALNO
bumpserialno();
#endif
/* at p, write size (SST bytes), id (1 byte), pad (SST-1 bytes) */
write_size_t(p, nbytes);
p[SST] = (uint8_t)api->api_id;
memset(p + SST + 1, PYMEM_FORBIDDENBYTE, SST-1);
if (nbytes > 0 && !use_calloc) {
memset(data, PYMEM_CLEANBYTE, nbytes);
}
/* at tail, write pad (SST bytes) and serialno (SST bytes) */
tail = data + nbytes;
memset(tail, PYMEM_FORBIDDENBYTE, SST);
#ifdef PYMEM_DEBUG_SERIALNO
write_size_t(tail + SST, serialno);
#endif
return data;
}
void *
_PyMem_DebugRawMalloc(void *ctx, size_t nbytes)
{
return _PyMem_DebugRawAlloc(0, ctx, nbytes);
}
void *
_PyMem_DebugRawCalloc(void *ctx, size_t nelem, size_t elsize)
{
size_t nbytes;
assert(elsize == 0 || nelem <= (size_t)PY_SSIZE_T_MAX / elsize);
nbytes = nelem * elsize;
return _PyMem_DebugRawAlloc(1, ctx, nbytes);
}
/* The debug free first checks the 2*SST bytes on each end for sanity (in
particular, that the FORBIDDENBYTEs with the api ID are still intact).
Then fills the original bytes with PYMEM_DEADBYTE.
Then calls the underlying free.
*/
void
_PyMem_DebugRawFree(void *ctx, void *p)
{
/* PyMem_Free(NULL) has no effect */
if (p == NULL) {
return;
}
debug_alloc_api_t *api = (debug_alloc_api_t *)ctx;
uint8_t *q = (uint8_t *)p - 2*SST; /* address returned from malloc */
size_t nbytes;
_PyMem_DebugCheckAddress(__func__, api->api_id, p);
nbytes = read_size_t(q);
nbytes += PYMEM_DEBUG_EXTRA_BYTES;
memset(q, PYMEM_DEADBYTE, nbytes);
api->alloc.free(api->alloc.ctx, q);
}
void *
_PyMem_DebugRawRealloc(void *ctx, void *p, size_t nbytes)
{
if (p == NULL) {
return _PyMem_DebugRawAlloc(0, ctx, nbytes);
}
debug_alloc_api_t *api = (debug_alloc_api_t *)ctx;
uint8_t *head; /* base address of malloc'ed pad block */
uint8_t *data; /* pointer to data bytes */
uint8_t *r;
uint8_t *tail; /* data + nbytes == pointer to tail pad bytes */
size_t total; /* 2 * SST + nbytes + 2 * SST */
size_t original_nbytes;
#define ERASED_SIZE 64
uint8_t save[2*ERASED_SIZE]; /* A copy of erased bytes. */
_PyMem_DebugCheckAddress(__func__, api->api_id, p);
data = (uint8_t *)p;
head = data - 2*SST;
original_nbytes = read_size_t(head);
if (nbytes > (size_t)PY_SSIZE_T_MAX - PYMEM_DEBUG_EXTRA_BYTES) {
/* integer overflow: can't represent total as a Py_ssize_t */
return NULL;
}
total = nbytes + PYMEM_DEBUG_EXTRA_BYTES;
tail = data + original_nbytes;
#ifdef PYMEM_DEBUG_SERIALNO
size_t block_serialno = read_size_t(tail + SST);
#endif
/* Mark the header, the trailer, ERASED_SIZE bytes at the begin and
ERASED_SIZE bytes at the end as dead and save the copy of erased bytes.
*/
if (original_nbytes <= sizeof(save)) {
memcpy(save, data, original_nbytes);
memset(data - 2 * SST, PYMEM_DEADBYTE,
original_nbytes + PYMEM_DEBUG_EXTRA_BYTES);
}
else {
memcpy(save, data, ERASED_SIZE);
memset(head, PYMEM_DEADBYTE, ERASED_SIZE + 2 * SST);
memcpy(&save[ERASED_SIZE], tail - ERASED_SIZE, ERASED_SIZE);
memset(tail - ERASED_SIZE, PYMEM_DEADBYTE,
ERASED_SIZE + PYMEM_DEBUG_EXTRA_BYTES - 2 * SST);
}
/* Resize and add decorations. */
r = (uint8_t *)api->alloc.realloc(api->alloc.ctx, head, total);
if (r == NULL) {
/* if realloc() failed: rewrite header and footer which have
just been erased */
nbytes = original_nbytes;
}
else {
head = r;
#ifdef PYMEM_DEBUG_SERIALNO
bumpserialno();
block_serialno = serialno;
#endif
}
data = head + 2*SST;
write_size_t(head, nbytes);
head[SST] = (uint8_t)api->api_id;
memset(head + SST + 1, PYMEM_FORBIDDENBYTE, SST-1);
tail = data + nbytes;
memset(tail, PYMEM_FORBIDDENBYTE, SST);
#ifdef PYMEM_DEBUG_SERIALNO
write_size_t(tail + SST, block_serialno);
#endif
/* Restore saved bytes. */
if (original_nbytes <= sizeof(save)) {
memcpy(data, save, Py_MIN(nbytes, original_nbytes));
}
else {
size_t i = original_nbytes - ERASED_SIZE;
memcpy(data, save, Py_MIN(nbytes, ERASED_SIZE));
if (nbytes > i) {
memcpy(data + i, &save[ERASED_SIZE],
Py_MIN(nbytes - i, ERASED_SIZE));
}
}
if (r == NULL) {
return NULL;
}
if (nbytes > original_nbytes) {
/* growing: mark new extra memory clean */
memset(data + original_nbytes, PYMEM_CLEANBYTE,
nbytes - original_nbytes);
}
return data;
}
static inline void
_PyMem_DebugCheckGIL(const char *func)
{
if (!PyGILState_Check()) {
_Py_FatalErrorFunc(func,
"Python memory allocator called "
"without holding the GIL");
}
}
void *
_PyMem_DebugMalloc(void *ctx, size_t nbytes)
{
_PyMem_DebugCheckGIL(__func__);
return _PyMem_DebugRawMalloc(ctx, nbytes);
}
void *
_PyMem_DebugCalloc(void *ctx, size_t nelem, size_t elsize)
{
_PyMem_DebugCheckGIL(__func__);
return _PyMem_DebugRawCalloc(ctx, nelem, elsize);
}
void
_PyMem_DebugFree(void *ctx, void *ptr)
{
_PyMem_DebugCheckGIL(__func__);
_PyMem_DebugRawFree(ctx, ptr);
}
void *
_PyMem_DebugRealloc(void *ctx, void *ptr, size_t nbytes)
{
_PyMem_DebugCheckGIL(__func__);
return _PyMem_DebugRawRealloc(ctx, ptr, nbytes);
}
/* Check the forbidden bytes on both ends of the memory allocated for p.
* If anything is wrong, print info to stderr via _PyObject_DebugDumpAddress,
* and call Py_FatalError to kill the program.
* The API id, is also checked.
*/
static void
_PyMem_DebugCheckAddress(const char *func, char api, const void *p)
{
assert(p != NULL);
const uint8_t *q = (const uint8_t *)p;
size_t nbytes;
const uint8_t *tail;
int i;
char id;
/* Check the API id */
id = (char)q[-SST];
if (id != api) {
_PyObject_DebugDumpAddress(p);
_Py_FatalErrorFormat(func,
"bad ID: Allocated using API '%c', "
"verified using API '%c'",
id, api);
}
/* Check the stuff at the start of p first: if there's underwrite
* corruption, the number-of-bytes field may be nuts, and checking
* the tail could lead to a segfault then.
*/
for (i = SST-1; i >= 1; --i) {
if (*(q-i) != PYMEM_FORBIDDENBYTE) {
_PyObject_DebugDumpAddress(p);
_Py_FatalErrorFunc(func, "bad leading pad byte");
}
}
nbytes = read_size_t(q - 2*SST);
tail = q + nbytes;
for (i = 0; i < SST; ++i) {
if (tail[i] != PYMEM_FORBIDDENBYTE) {
_PyObject_DebugDumpAddress(p);
_Py_FatalErrorFunc(func, "bad trailing pad byte");
}
}
}
/* Display info to stderr about the memory block at p. */
static void
_PyObject_DebugDumpAddress(const void *p)
{
const uint8_t *q = (const uint8_t *)p;
const uint8_t *tail;
size_t nbytes;
int i;
int ok;
char id;
fprintf(stderr, "Debug memory block at address p=%p:", p);
if (p == NULL) {
fprintf(stderr, "\n");
return;
}
id = (char)q[-SST];
fprintf(stderr, " API '%c'\n", id);
nbytes = read_size_t(q - 2*SST);
fprintf(stderr, " %zu bytes originally requested\n", nbytes);
/* In case this is nuts, check the leading pad bytes first. */
fprintf(stderr, " The %d pad bytes at p-%d are ", SST-1, SST-1);
ok = 1;
for (i = 1; i <= SST-1; ++i) {
if (*(q-i) != PYMEM_FORBIDDENBYTE) {
ok = 0;
break;
}
}
if (ok)
fputs("FORBIDDENBYTE, as expected.\n", stderr);
else {
fprintf(stderr, "not all FORBIDDENBYTE (0x%02x):\n",
PYMEM_FORBIDDENBYTE);
for (i = SST-1; i >= 1; --i) {
const uint8_t byte = *(q-i);
fprintf(stderr, " at p-%d: 0x%02x", i, byte);
if (byte != PYMEM_FORBIDDENBYTE)
fputs(" *** OUCH", stderr);
fputc('\n', stderr);
}
fputs(" Because memory is corrupted at the start, the "
"count of bytes requested\n"
" may be bogus, and checking the trailing pad "
"bytes may segfault.\n", stderr);
}
tail = q + nbytes;
fprintf(stderr, " The %d pad bytes at tail=%p are ", SST, (void *)tail);
ok = 1;
for (i = 0; i < SST; ++i) {
if (tail[i] != PYMEM_FORBIDDENBYTE) {
ok = 0;
break;
}
}
if (ok)
fputs("FORBIDDENBYTE, as expected.\n", stderr);
else {
fprintf(stderr, "not all FORBIDDENBYTE (0x%02x):\n",
PYMEM_FORBIDDENBYTE);
for (i = 0; i < SST; ++i) {
const uint8_t byte = tail[i];
fprintf(stderr, " at tail+%d: 0x%02x",
i, byte);
if (byte != PYMEM_FORBIDDENBYTE)
fputs(" *** OUCH", stderr);
fputc('\n', stderr);
}
}
#ifdef PYMEM_DEBUG_SERIALNO
size_t serial = read_size_t(tail + SST);
fprintf(stderr,
" The block was made by call #%zu to debug malloc/realloc.\n",
serial);
#endif
if (nbytes > 0) {
i = 0;
fputs(" Data at p:", stderr);
/* print up to 8 bytes at the start */
while (q < tail && i < 8) {
fprintf(stderr, " %02x", *q);
++i;
++q;
}
/* and up to 8 at the end */
if (q < tail) {
if (tail - q > 8) {
fputs(" ...", stderr);
q = tail - 8;
}
while (q < tail) {
fprintf(stderr, " %02x", *q);
++q;
}
}
fputc('\n', stderr);
}
fputc('\n', stderr);
fflush(stderr);
_PyMem_DumpTraceback(fileno(stderr), p);
}
static size_t
printone(FILE *out, const char* msg, size_t value)
{
int i, k;
char buf[100];
size_t origvalue = value;
fputs(msg, out);
for (i = (int)strlen(msg); i < 35; ++i)
fputc(' ', out);
fputc('=', out);
/* Write the value with commas. */
i = 22;
buf[i--] = '\0';
buf[i--] = '\n';
k = 3;
do {
size_t nextvalue = value / 10;
unsigned int digit = (unsigned int)(value - nextvalue * 10);
value = nextvalue;
buf[i--] = (char)(digit + '0');
--k;
if (k == 0 && value && i >= 0) {
k = 3;
buf[i--] = ',';
}
} while (value && i >= 0);
while (i >= 0)
buf[i--] = ' ';
fputs(buf, out);
return origvalue;
}
void
_PyDebugAllocatorStats(FILE *out,
const char *block_name, int num_blocks, size_t sizeof_block)
{
char buf1[128];
char buf2[128];
PyOS_snprintf(buf1, sizeof(buf1),
"%d %ss * %zd bytes each",
num_blocks, block_name, sizeof_block);
PyOS_snprintf(buf2, sizeof(buf2),
"%48s ", buf1);
(void)printone(out, buf2, num_blocks * sizeof_block);
}
#ifdef WITH_PYMALLOC
#ifdef Py_DEBUG
/* Is target in the list? The list is traversed via the nextpool pointers.
* The list may be NULL-terminated, or circular. Return 1 if target is in
* list, else 0.
*/
static int
pool_is_in_list(const poolp target, poolp list)
{
poolp origlist = list;
assert(target != NULL);
if (list == NULL)
return 0;
do {
if (target == list)
return 1;
list = list->nextpool;
} while (list != NULL && list != origlist);
return 0;
}
#endif
/* Print summary info to "out" about the state of pymalloc's structures.
* In Py_DEBUG mode, also perform some expensive internal consistency
* checks.
*
* Return 0 if the memory debug hooks are not installed or no statistics was
* written into out, return 1 otherwise.
*/
int
_PyObject_DebugMallocStats(FILE *out)
{
if (!_PyMem_PymallocEnabled()) {
return 0;
}
OMState *state = get_state();
uint i;
const uint numclasses = SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT;
/* # of pools, allocated blocks, and free blocks per class index */
size_t numpools[SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT];
size_t numblocks[SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT];
size_t numfreeblocks[SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT];
/* total # of allocated bytes in used and full pools */
size_t allocated_bytes = 0;
/* total # of available bytes in used pools */
size_t available_bytes = 0;
/* # of free pools + pools not yet carved out of current arena */
uint numfreepools = 0;
/* # of bytes for arena alignment padding */
size_t arena_alignment = 0;
/* # of bytes in used and full pools used for pool_headers */
size_t pool_header_bytes = 0;
/* # of bytes in used and full pools wasted due to quantization,
* i.e. the necessarily leftover space at the ends of used and
* full pools.
*/
size_t quantization = 0;
/* # of arenas actually allocated. */
size_t narenas = 0;
/* running total -- should equal narenas * ARENA_SIZE */
size_t total;
char buf[128];
fprintf(out, "Small block threshold = %d, in %u size classes.\n",
SMALL_REQUEST_THRESHOLD, numclasses);
for (i = 0; i < numclasses; ++i)
numpools[i] = numblocks[i] = numfreeblocks[i] = 0;
/* Because full pools aren't linked to from anything, it's easiest
* to march over all the arenas. If we're lucky, most of the memory
* will be living in full pools -- would be a shame to miss them.
*/
for (i = 0; i < maxarenas; ++i) {
uintptr_t base = allarenas[i].address;
/* Skip arenas which are not allocated. */
if (allarenas[i].address == (uintptr_t)NULL)
continue;
narenas += 1;
numfreepools += allarenas[i].nfreepools;
/* round up to pool alignment */
if (base & (uintptr_t)POOL_SIZE_MASK) {
arena_alignment += POOL_SIZE;
base &= ~(uintptr_t)POOL_SIZE_MASK;
base += POOL_SIZE;
}
/* visit every pool in the arena */
assert(base <= (uintptr_t) allarenas[i].pool_address);
for (; base < (uintptr_t) allarenas[i].pool_address; base += POOL_SIZE) {
poolp p = (poolp)base;
const uint sz = p->szidx;
uint freeblocks;
if (p->ref.count == 0) {
/* currently unused */
#ifdef Py_DEBUG
assert(pool_is_in_list(p, allarenas[i].freepools));
#endif
continue;
}
++numpools[sz];
numblocks[sz] += p->ref.count;
freeblocks = NUMBLOCKS(sz) - p->ref.count;
numfreeblocks[sz] += freeblocks;
#ifdef Py_DEBUG
if (freeblocks > 0)
assert(pool_is_in_list(p, usedpools[sz + sz]));
#endif
}
}
assert(narenas == narenas_currently_allocated);
fputc('\n', out);
fputs("class size num pools blocks in use avail blocks\n"
"----- ---- --------- ------------- ------------\n",
out);
for (i = 0; i < numclasses; ++i) {
size_t p = numpools[i];
size_t b = numblocks[i];
size_t f = numfreeblocks[i];
uint size = INDEX2SIZE(i);
if (p == 0) {
assert(b == 0 && f == 0);
continue;
}
fprintf(out, "%5u %6u %11zu %15zu %13zu\n",
i, size, p, b, f);
allocated_bytes += b * size;
available_bytes += f * size;
pool_header_bytes += p * POOL_OVERHEAD;
quantization += p * ((POOL_SIZE - POOL_OVERHEAD) % size);
}
fputc('\n', out);
#ifdef PYMEM_DEBUG_SERIALNO
if (_PyMem_DebugEnabled()) {
(void)printone(out, "# times object malloc called", serialno);
}
#endif
(void)printone(out, "# arenas allocated total", ntimes_arena_allocated);
(void)printone(out, "# arenas reclaimed", ntimes_arena_allocated - narenas);
(void)printone(out, "# arenas highwater mark", narenas_highwater);
(void)printone(out, "# arenas allocated current", narenas);
PyOS_snprintf(buf, sizeof(buf),
"%zu arenas * %d bytes/arena",
narenas, ARENA_SIZE);
(void)printone(out, buf, narenas * ARENA_SIZE);
fputc('\n', out);
/* Account for what all of those arena bytes are being used for. */
total = printone(out, "# bytes in allocated blocks", allocated_bytes);
total += printone(out, "# bytes in available blocks", available_bytes);
PyOS_snprintf(buf, sizeof(buf),
"%u unused pools * %d bytes", numfreepools, POOL_SIZE);
total += printone(out, buf, (size_t)numfreepools * POOL_SIZE);
total += printone(out, "# bytes lost to pool headers", pool_header_bytes);
total += printone(out, "# bytes lost to quantization", quantization);
total += printone(out, "# bytes lost to arena alignment", arena_alignment);
(void)printone(out, "Total", total);
assert(narenas * ARENA_SIZE == total);
#if WITH_PYMALLOC_RADIX_TREE
fputs("\narena map counts\n", out);
#ifdef USE_INTERIOR_NODES
(void)printone(out, "# arena map mid nodes", arena_map_mid_count);
(void)printone(out, "# arena map bot nodes", arena_map_bot_count);
fputc('\n', out);
#endif
total = printone(out, "# bytes lost to arena map root", sizeof(arena_map_root));
#ifdef USE_INTERIOR_NODES
total += printone(out, "# bytes lost to arena map mid",
sizeof(arena_map_mid_t) * arena_map_mid_count);
total += printone(out, "# bytes lost to arena map bot",
sizeof(arena_map_bot_t) * arena_map_bot_count);
(void)printone(out, "Total", total);
#endif
#endif
return 1;
}
#endif /* #ifdef WITH_PYMALLOC */
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