Revert changeset 6661a8154eb3: Issue #3329: Add new APIs to customize memory allocators
The new API require more discussion.
diff --git a/Objects/object.c b/Objects/object.c
index d382a3c..79f1c8a 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -1859,6 +1859,26 @@
Py_ssize_t (*_Py_abstract_hack)(PyObject *) = PyObject_Size;
+/* Python's malloc wrappers (see pymem.h) */
+
+void *
+PyMem_Malloc(size_t nbytes)
+{
+ return PyMem_MALLOC(nbytes);
+}
+
+void *
+PyMem_Realloc(void *p, size_t nbytes)
+{
+ return PyMem_REALLOC(p, nbytes);
+}
+
+void
+PyMem_Free(void *p)
+{
+ PyMem_FREE(p);
+}
+
void
_PyObject_DebugTypeStats(FILE *out)
{
diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c
index 6dceb38..3028f22 100644
--- a/Objects/obmalloc.c
+++ b/Objects/obmalloc.c
@@ -1,327 +1,5 @@
#include "Python.h"
-/* Python's malloc wrappers (see pymem.h) */
-
-/* Forward declaration */
-
-#ifdef PYMALLOC_DEBUG /* WITH_PYMALLOC && PYMALLOC_DEBUG */
-static void* _PyMem_DebugMalloc(void *ctx, size_t size);
-static void _PyMem_DebugFree(void *ctx, void *p);
-static void* _PyMem_DebugRealloc(void *ctx, void *ptr, size_t size);
-
-static void _PyObject_DebugDumpAddress(const void *p);
-static void _PyMem_DebugCheckAddress(char api_id, const void *p);
-#endif
-
-#ifdef WITH_PYMALLOC
-static void* _PyObject_Malloc(void *ctx, size_t size);
-static void _PyObject_Free(void *ctx, void *p);
-static void* _PyObject_Realloc(void *ctx, void *ptr, size_t size);
-#endif
-
-
-static void *
-_PyMem_RawMalloc(void *ctx, size_t size)
-{
- return malloc(size);
-}
-
-static void *
-_PyMem_RawRealloc(void *ctx, void *ptr, size_t size)
-{
- return realloc(ptr, size);
-}
-
-static void
-_PyMem_RawFree(void *ctx, void *ptr)
-{
- return free(ptr);
-}
-
-static void *
-_PyMem_Malloc(void *ctx, size_t size)
-{
- /* PyMem_Malloc(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);
-}
-
-static void *
-_PyMem_Realloc(void *ctx, void *ptr, size_t size)
-{
- if (size == 0)
- size = 1;
- return realloc(ptr, size);
-}
-
-#ifdef ARENAS_USE_MMAP
-static void *
-_PyObject_ArenaMmap(void *ctx, size_t size)
-{
- 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;
-}
-
-static void
-_PyObject_ArenaMunmap(void *ctx, void *ptr, size_t size)
-{
- return munmap(ptr, size);
-}
-#else
-static void *
-_PyObject_ArenaMalloc(void *ctx, size_t size)
-{
- return malloc(size);
-}
-
-static void
-_PyObject_ArenaFree(void *ctx, void *ptr, size_t size)
-{
- free(ptr);
-}
-#endif
-
-#define PYRAW_FUNCS _PyMem_RawMalloc, _PyMem_RawRealloc, _PyMem_RawFree
-#define PYMEM_FUNCS _PyMem_Malloc, _PyMem_Realloc, _PyMem_RawFree
-#ifdef WITH_PYMALLOC
-#define PYOBJECT_FUNCS _PyObject_Malloc, _PyObject_Realloc, _PyObject_Free
-#else
-#define PYOBJECT_FUNCS PYMEM_FUNCS
-#endif
-
-#ifdef PYMALLOC_DEBUG
-typedef struct {
- /* We tag each block with an API ID in order to tag API violations */
- char api_id;
- PyMemAllocators alloc;
-} debug_alloc_api_t;
-static struct {
- debug_alloc_api_t raw;
- debug_alloc_api_t mem;
- debug_alloc_api_t obj;
-} _PyMem_Debug = {
- {'r', {NULL, PYRAW_FUNCS}},
- {'m', {NULL, PYMEM_FUNCS}},
- {'o', {NULL, PYOBJECT_FUNCS}}
- };
-
-#define PYDEBUG_FUNCS _PyMem_DebugMalloc, _PyMem_DebugRealloc, _PyMem_DebugFree
-#endif
-
-static PyMemAllocators _PyMem_Raw = {
-#ifdef PYMALLOC_DEBUG
- &_PyMem_Debug.raw, PYDEBUG_FUNCS
-#else
- NULL, PYMEM_FUNCS
-#endif
- };
-
-static PyMemAllocators _PyMem = {
-#ifdef PYMALLOC_DEBUG
- &_PyMem_Debug.mem, PYDEBUG_FUNCS
-#else
- NULL, PYMEM_FUNCS
-#endif
- };
-
-static PyMemAllocators _PyObject = {
-#ifdef PYMALLOC_DEBUG
- &_PyMem_Debug.obj, PYDEBUG_FUNCS
-#else
- NULL, PYOBJECT_FUNCS
-#endif
- };
-
-#undef PYRAW_FUNCS
-#undef PYMEM_FUNCS
-#undef PYOBJECT_FUNCS
-#undef PYDEBUG_FUNCS
-
-static struct {
- void *ctx;
- void* (*malloc) (void*, size_t);
- void (*free) (void*, void*, size_t);
-} _PyObject_Arena = {NULL,
-#ifdef ARENAS_USE_MMAP
- _PyObject_ArenaMmap, _PyObject_ArenaMunmap
-#else
- _PyObject_ArenaMalloc, _PyObject_ArenaFree
-#endif
- };
-
-void
-PyMem_SetupDebugHooks(void)
-{
-#ifdef PYMALLOC_DEBUG
- PyMemAllocators alloc;
-
- alloc.malloc = _PyMem_DebugMalloc;
- alloc.realloc = _PyMem_DebugRealloc;
- alloc.free = _PyMem_DebugFree;
-
- if (_PyMem_Raw.malloc != _PyMem_DebugMalloc) {
- alloc.ctx = &_PyMem_Debug.raw;
- PyMem_GetAllocators(&_PyMem_Debug.raw.alloc);
- PyMem_SetAllocators(&alloc);
- }
-
- if (_PyMem.malloc != _PyMem_DebugMalloc) {
- alloc.ctx = &_PyMem_Debug.mem;
- PyMem_GetAllocators(&_PyMem_Debug.mem.alloc);
- PyMem_SetAllocators(&alloc);
- }
-
- if (_PyObject.malloc != _PyMem_DebugMalloc) {
- alloc.ctx = &_PyMem_Debug.obj;
- PyObject_GetAllocators(&_PyMem_Debug.obj.alloc);
- PyObject_SetAllocators(&alloc);
- }
-#endif
-}
-
-void
-PyMem_GetRawAllocators(PyMemAllocators *allocators)
-{
- *allocators = _PyMem_Raw;
-}
-
-void
-PyMem_SetRawAllocators(PyMemAllocators *allocators)
-{
- _PyMem_Raw = *allocators;
-}
-
-void
-PyMem_GetAllocators(PyMemAllocators *allocators)
-{
- *allocators = _PyMem;
-}
-
-void
-PyMem_SetAllocators(PyMemAllocators *allocators)
-{
- _PyMem = *allocators;
-}
-
-void
-PyObject_GetAllocators(PyMemAllocators *allocators)
-{
- *allocators = _PyObject;
-}
-
-void
-PyObject_SetAllocators(PyMemAllocators *allocators)
-{
- _PyObject = *allocators;
-}
-
-void
-_PyObject_GetArenaAllocators(void **ctx_p,
- void* (**malloc_p) (void *ctx, size_t size),
- void (**free_p) (void *ctx, void *ptr, size_t size))
-{
- *malloc_p = _PyObject_Arena.malloc;
- *free_p = _PyObject_Arena.free;
- *ctx_p = _PyObject_Arena.ctx;
-}
-
-void
-_PyObject_SetArenaAllocators(void *ctx,
- void* (*malloc) (void *ctx, size_t size),
- void (*free) (void *ctx, void *ptr, size_t size))
-{
- _PyObject_Arena.malloc = malloc;
- _PyObject_Arena.free = free;
- _PyObject_Arena.ctx = ctx;
-}
-
-void *
-PyMem_RawMalloc(size_t size)
-{
- return _PyMem_Raw.malloc(_PyMem_Raw.ctx, size);
-}
-
-void*
-PyMem_RawRealloc(void *ptr, size_t new_size)
-{
- return _PyMem_Raw.realloc(_PyMem_Raw.ctx, ptr, new_size);
-}
-
-void PyMem_RawFree(void *ptr)
-{
- _PyMem_Raw.free(_PyMem_Raw.ctx, ptr);
-}
-
-void *
-PyMem_Malloc(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.malloc(_PyMem.ctx, size);
-}
-
-void *
-PyMem_Realloc(void *ptr, size_t new_size)
-{
- if (new_size > (size_t)PY_SSIZE_T_MAX)
- return NULL;
-
- return _PyMem.realloc(_PyMem.ctx, ptr, new_size);
-}
-
-void
-PyMem_Free(void *ptr)
-{
- _PyMem.free(_PyMem.ctx, ptr);
-}
-
-void *
-PyObject_Malloc(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 _PyObject.malloc(_PyObject.ctx, size);
-}
-
-void *
-PyObject_Realloc(void *ptr, size_t new_size)
-{
- if (new_size > (size_t)PY_SSIZE_T_MAX)
- return NULL;
-
- return _PyObject.realloc(_PyObject.ctx, ptr, new_size);
-}
-
-void
-PyObject_Free(void *ptr)
-{
- _PyObject.free(_PyObject.ctx, ptr);
-}
-
-
#ifdef WITH_PYMALLOC
#ifdef HAVE_MMAP
@@ -867,6 +545,7 @@
struct arena_object* arenaobj;
uint excess; /* number of bytes above pool alignment */
void *address;
+ int err;
#ifdef PYMALLOC_DEBUG
if (Py_GETENV("PYTHONMALLOCSTATS"))
@@ -888,12 +567,11 @@
return NULL; /* overflow */
#endif
nbytes = numarenas * sizeof(*arenas);
- arenaobj = (struct arena_object *)PyMem_Realloc(arenas, nbytes);
+ arenaobj = (struct arena_object *)realloc(arenas, nbytes);
if (arenaobj == NULL)
return NULL;
arenas = 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
@@ -920,8 +598,15 @@
arenaobj = unused_arena_objects;
unused_arena_objects = arenaobj->nextarena;
assert(arenaobj->address == 0);
- address = _PyObject_Arena.malloc(_PyObject_Arena.ctx, ARENA_SIZE);
- if (address == NULL) {
+#ifdef ARENAS_USE_MMAP
+ address = mmap(NULL, ARENA_SIZE, PROT_READ|PROT_WRITE,
+ MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ err = (address == MAP_FAILED);
+#else
+ address = malloc(ARENA_SIZE);
+ err = (address == 0);
+#endif
+ if (err) {
/* The allocation failed: return NULL after putting the
* arenaobj back.
*/
@@ -1084,8 +769,9 @@
* Unless the optimizer reorders everything, being too smart...
*/
-static void *
-_PyObject_Malloc(void *ctx, size_t nbytes)
+#undef PyObject_Malloc
+void *
+PyObject_Malloc(size_t nbytes)
{
block *bp;
poolp pool;
@@ -1102,6 +788,17 @@
#endif
/*
+ * 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 nbytes < 0 is not required.
+ */
+ if (nbytes > PY_SSIZE_T_MAX) {
+ _Py_AllocatedBlocks--;
+ return NULL;
+ }
+
+ /*
* This implicitly redirects malloc(0).
*/
if ((nbytes - 1) < SMALL_REQUEST_THRESHOLD) {
@@ -1273,8 +970,10 @@
* last chance to serve the request) or when the max memory limit
* has been reached.
*/
+ if (nbytes == 0)
+ nbytes = 1;
{
- void *result = PyMem_Malloc(nbytes);
+ void *result = malloc(nbytes);
if (!result)
_Py_AllocatedBlocks--;
return result;
@@ -1283,8 +982,9 @@
/* free */
-static void
-_PyObject_Free(void *ctx, void *p)
+#undef PyObject_Free
+void
+PyObject_Free(void *p)
{
poolp pool;
block *lastfree;
@@ -1393,8 +1093,11 @@
unused_arena_objects = ao;
/* Free the entire arena. */
- _PyObject_Arena.free(_PyObject_Arena.ctx,
- (void *)ao->address, ARENA_SIZE);
+#ifdef ARENAS_USE_MMAP
+ munmap((void *)ao->address, ARENA_SIZE);
+#else
+ free((void *)ao->address);
+#endif
ao->address = 0; /* mark unassociated */
--narenas_currently_allocated;
@@ -1503,7 +1206,7 @@
redirect:
#endif
/* We didn't allocate this address. */
- PyMem_Free(p);
+ free(p);
}
/* realloc. If p is NULL, this acts like malloc(nbytes). Else if nbytes==0,
@@ -1511,8 +1214,9 @@
* return a non-NULL result.
*/
-static void *
-_PyObject_Realloc(void *ctx, void *p, size_t nbytes)
+#undef PyObject_Realloc
+void *
+PyObject_Realloc(void *p, size_t nbytes)
{
void *bp;
poolp pool;
@@ -1522,7 +1226,16 @@
#endif
if (p == NULL)
- return _PyObject_Malloc(ctx, nbytes);
+ return PyObject_Malloc(nbytes);
+
+ /*
+ * 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 nbytes < 0 is not required.
+ */
+ if (nbytes > PY_SSIZE_T_MAX)
+ return NULL;
#ifdef WITH_VALGRIND
/* Treat running_on_valgrind == -1 the same as 0 */
@@ -1550,10 +1263,10 @@
}
size = nbytes;
}
- bp = _PyObject_Malloc(ctx, nbytes);
+ bp = PyObject_Malloc(nbytes);
if (bp != NULL) {
memcpy(bp, p, size);
- _PyObject_Free(ctx, p);
+ PyObject_Free(p);
}
return bp;
}
@@ -1571,14 +1284,14 @@
* at p. Instead we punt: let C continue to manage this block.
*/
if (nbytes)
- return PyMem_Realloc(p, nbytes);
+ return realloc(p, nbytes);
/* C doesn't define the result of realloc(p, 0) (it may or may not
* return NULL then), but Python's docs promise that nbytes==0 never
* returns NULL. We don't pass 0 to realloc(), to avoid that endcase
* to begin with. Even then, we can't be sure that realloc() won't
* return NULL.
*/
- bp = PyMem_Realloc(p, 1);
+ bp = realloc(p, 1);
return bp ? bp : p;
}
@@ -1588,6 +1301,24 @@
/* pymalloc not enabled: Redirect the entry points to malloc. These will
* only be used by extensions that are compiled with pymalloc enabled. */
+void *
+PyObject_Malloc(size_t n)
+{
+ return PyMem_MALLOC(n);
+}
+
+void *
+PyObject_Realloc(void *p, size_t n)
+{
+ return PyMem_REALLOC(p, n);
+}
+
+void
+PyObject_Free(void *p)
+{
+ PyMem_FREE(p);
+}
+
Py_ssize_t
_Py_GetAllocatedBlocks(void)
{
@@ -1613,6 +1344,10 @@
#define DEADBYTE 0xDB /* dead (newly freed) memory */
#define FORBIDDENBYTE 0xFB /* untouchable bytes at each end of a block */
+/* We tag each block with an API ID in order to tag API violations */
+#define _PYMALLOC_MEM_ID 'm' /* the PyMem_Malloc() API */
+#define _PYMALLOC_OBJ_ID 'o' /* The PyObject_Malloc() API */
+
static size_t serialno = 0; /* incremented on each debug {m,re}alloc */
/* serialno is always incremented via calling this routine. The point is
@@ -1695,18 +1430,58 @@
p[2*S+n: 2*S+n+S]
Copies of 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.
+ A serial number, incremented by 1 on each call to _PyObject_DebugMalloc
+ and _PyObject_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.
*/
-static void *
-_PyMem_DebugMalloc(void *ctx, size_t nbytes)
+/* debug replacements for the PyMem_* memory API */
+void *
+_PyMem_DebugMalloc(size_t nbytes)
{
- debug_alloc_api_t *api = (debug_alloc_api_t *)ctx;
+ return _PyObject_DebugMallocApi(_PYMALLOC_MEM_ID, nbytes);
+}
+void *
+_PyMem_DebugRealloc(void *p, size_t nbytes)
+{
+ return _PyObject_DebugReallocApi(_PYMALLOC_MEM_ID, p, nbytes);
+}
+void
+_PyMem_DebugFree(void *p)
+{
+ _PyObject_DebugFreeApi(_PYMALLOC_MEM_ID, p);
+}
+
+/* debug replacements for the PyObject_* memory API */
+void *
+_PyObject_DebugMalloc(size_t nbytes)
+{
+ return _PyObject_DebugMallocApi(_PYMALLOC_OBJ_ID, nbytes);
+}
+void *
+_PyObject_DebugRealloc(void *p, size_t nbytes)
+{
+ return _PyObject_DebugReallocApi(_PYMALLOC_OBJ_ID, p, nbytes);
+}
+void
+_PyObject_DebugFree(void *p)
+{
+ _PyObject_DebugFreeApi(_PYMALLOC_OBJ_ID, p);
+}
+void
+_PyObject_DebugCheckAddress(const void *p)
+{
+ _PyObject_DebugCheckAddressApi(_PYMALLOC_OBJ_ID, p);
+}
+
+
+/* generic debug memory api, with an "id" to identify the API in use */
+void *
+_PyObject_DebugMallocApi(char id, size_t nbytes)
+{
uchar *p; /* base address of malloc'ed block */
uchar *tail; /* p + 2*SST + nbytes == pointer to tail pad bytes */
size_t total; /* nbytes + 4*SST */
@@ -1717,14 +1492,14 @@
/* overflow: can't represent total as a size_t */
return NULL;
- p = (uchar *)api->alloc.malloc(api->alloc.ctx, total);
+ p = (uchar *)PyObject_Malloc(total);
if (p == NULL)
return NULL;
/* at p, write size (SST bytes), id (1 byte), pad (SST-1 bytes) */
write_size_t(p, nbytes);
- p[SST] = (uchar)api->api_id;
- memset(p + SST + 1, FORBIDDENBYTE, SST-1);
+ p[SST] = (uchar)id;
+ memset(p + SST + 1 , FORBIDDENBYTE, SST-1);
if (nbytes > 0)
memset(p + 2*SST, CLEANBYTE, nbytes);
@@ -1742,27 +1517,25 @@
Then fills the original bytes with DEADBYTE.
Then calls the underlying free.
*/
-static void
-_PyMem_DebugFree(void *ctx, void *p)
+void
+_PyObject_DebugFreeApi(char api, void *p)
{
- debug_alloc_api_t *api = (debug_alloc_api_t *)ctx;
uchar *q = (uchar *)p - 2*SST; /* address returned from malloc */
size_t nbytes;
if (p == NULL)
return;
- _PyMem_DebugCheckAddress(api->api_id, p);
+ _PyObject_DebugCheckAddressApi(api, p);
nbytes = read_size_t(q);
nbytes += 4*SST;
if (nbytes > 0)
memset(q, DEADBYTE, nbytes);
- api->alloc.free(api->alloc.ctx, q);
+ PyObject_Free(q);
}
-static void *
-_PyMem_DebugRealloc(void *ctx, void *p, size_t nbytes)
+void *
+_PyObject_DebugReallocApi(char api, void *p, size_t nbytes)
{
- debug_alloc_api_t *api = (debug_alloc_api_t *)ctx;
uchar *q = (uchar *)p;
uchar *tail;
size_t total; /* nbytes + 4*SST */
@@ -1770,9 +1543,9 @@
int i;
if (p == NULL)
- return _PyMem_DebugMalloc(ctx, nbytes);
+ return _PyObject_DebugMallocApi(api, nbytes);
- _PyMem_DebugCheckAddress(api->api_id, p);
+ _PyObject_DebugCheckAddressApi(api, p);
bumpserialno();
original_nbytes = read_size_t(q - 2*SST);
total = nbytes + 4*SST;
@@ -1789,12 +1562,12 @@
* case we didn't get the chance to mark the old memory with DEADBYTE,
* but we live with that.
*/
- q = (uchar *)api->alloc.realloc(api->alloc.ctx, q - 2*SST, total);
+ q = (uchar *)PyObject_Realloc(q - 2*SST, total);
if (q == NULL)
return NULL;
write_size_t(q, nbytes);
- assert(q[SST] == (uchar)api->api_id);
+ assert(q[SST] == (uchar)api);
for (i = 1; i < SST; ++i)
assert(q[SST + i] == FORBIDDENBYTE);
q += 2*SST;
@@ -1816,8 +1589,8 @@
* and call Py_FatalError to kill the program.
* The API id, is also checked.
*/
-static void
-_PyMem_DebugCheckAddress(char api, const void *p)
+ void
+_PyObject_DebugCheckAddressApi(char api, const void *p)
{
const uchar *q = (const uchar *)p;
char msgbuf[64];
@@ -1869,7 +1642,7 @@
}
/* Display info to stderr about the memory block at p. */
-static void
+void
_PyObject_DebugDumpAddress(const void *p)
{
const uchar *q = (const uchar *)p;