Include/pymem.h

#define PyMem_MALLOC(n) ((size_t)(n) > (size_t)PY_SSIZE_T_MAX ? NULL \
             : malloc((n) ? (n) : 1))
#define PyMem_REALLOC(p, n) ((size_t)(n) > (size_t)PY_SSIZE_T_MAX ? NULL \
              : realloc((p), (n) ? (n) : 1))
#define PyMem_FREE free

  Objects/object.c

/* Python's malloc wrappers (see pymem.h) */

void *
PyMem_Malloc(size_t nbytes)
{
  return PyMem_MALLOC(nbytes);
}
...

#define PyMem_New(type, n) \
 ( ((size_t)(n) > PY_SSIZE_T_MAX / sizeof(type)) ? NULL :   \
    ( (type *) PyMem_Malloc((n) * sizeof(type)) ) )

#define PyMem_Resize(p, type, n) \
 ( (p) = ((size_t)(n) > PY_SSIZE_T_MAX / sizeof(type)) ? NULL :    \
    (type *) PyMem_Realloc((p), (n) * sizeof(type)) )
#define PyMem_Del        PyMem_Free
#define PyMem_DEL        PyMem_FREE

  Include/objimpl.h

#define PyObject_New(type, typeobj) \
        ( (type *) _PyObject_New(typeobj) )
#define PyObject_NewVar(type, typeobj, n) \
        ( (type *) _PyObject_NewVar((typeobj), (n)) )

  Objects/object.c

PyObject *
_PyObject_New(PyTypeObject *tp)
{
  PyObject *op;
  op = (PyObject *) PyObject_MALLOC(_PyObject_SIZE(tp));
  if (op == NULL)
    return PyErr_NoMemory();
  return PyObject_INIT(op, tp);
}

PyVarObject *
_PyObject_NewVar(PyTypeObject *tp, Py_ssize_t nitems)
{
  PyVarObject *op;
  const size_t size = _PyObject_VAR_SIZE(tp, nitems);
  op = (PyVarObject *) PyObject_MALLOC(size);
  if (op == NULL)
    return (PyVarObject *)PyErr_NoMemory();
  return PyObject_INIT_VAR(op, tp, nitems);
}

void * PyObject_Malloc(size_t nbytes)
void * PyObject_Realloc(void *p, size_t nbytes)
void PyObject_Free(void *p)

#define ALIGNMENT        8        /* must be 2^N */
/* Return the number of bytes in size class I, as a uint. */
#define INDEX2SIZE(I) (((uint)(I) + 1) << ALIGNMENT_SHIFT)
#define SMALL_REQUEST_THRESHOLD 256

struct pool_header {
  union { block *_padding;
      uint count; } ref;     /* number of allocated blocks  */
  block *freeblock;          /* pool's free list head     */
  struct pool_header *nextpool;    /* next pool of this size class */
  struct pool_header *prevpool;    /* previous pool    ""    */
  uint arenaindex;          /* index into arenas of base adr */
  uint szidx;             /* block size class index    */
  uint nextoffset;          /* bytes to virgin block     */
  uint maxnextoffset;         /* largest valid nextoffset   */
};

struct arena_object {
  uptr address;
  block* pool_address;
  uint nfreepools;
  uint ntotalpools;
  struct pool_header* freepools;
  struct arena_object* nextarena;
  struct arena_object* prevarena;
};

#define ARENA_SIZE       (256 << 10)   /* 256KB */