From 17d31bf3843c384873999a15ce683cc3654f46ae Mon Sep 17 00:00:00 2001 From: Donghee Na Date: Sun, 10 Mar 2024 08:50:28 +0900 Subject: [PATCH] gh-112087: Store memory allocation information into _PyListArray (gh-116529) --- ...-03-09-11-10-53.gh-issue-112087.nbI0Pw.rst | 1 + Objects/listobject.c | 126 ++++++++++++++++-- 2 files changed, 113 insertions(+), 14 deletions(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2024-03-09-11-10-53.gh-issue-112087.nbI0Pw.rst diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-03-09-11-10-53.gh-issue-112087.nbI0Pw.rst b/Misc/NEWS.d/next/Core and Builtins/2024-03-09-11-10-53.gh-issue-112087.nbI0Pw.rst new file mode 100644 index 00000000000..07808dc3256 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2024-03-09-11-10-53.gh-issue-112087.nbI0Pw.rst @@ -0,0 +1 @@ +:class:`list` is now compatible with the implementation of :pep:`703`. diff --git a/Objects/listobject.c b/Objects/listobject.c index e013383a712..c2aaab0ec3b 100644 --- a/Objects/listobject.c +++ b/Objects/listobject.c @@ -31,6 +31,50 @@ get_list_freelist(void) } #endif +#ifdef Py_GIL_DISABLED +typedef struct { + Py_ssize_t allocated; + PyObject *ob_item[]; +} _PyListArray; + +static _PyListArray * +list_allocate_array(size_t capacity) +{ + if (capacity > PY_SSIZE_T_MAX/sizeof(PyObject*) - 1) { + return NULL; + } + _PyListArray *array = PyMem_Malloc(sizeof(_PyListArray) + capacity * sizeof(PyObject *)); + if (array == NULL) { + return NULL; + } + array->allocated = capacity; + return array; +} + +static Py_ssize_t +list_capacity(PyObject **items) +{ + _PyListArray *array = _Py_CONTAINER_OF(items, _PyListArray, ob_item); + return array->allocated; +} +#endif + +static void +free_list_items(PyObject** items, bool use_qsbr) +{ +#ifdef Py_GIL_DISABLED + _PyListArray *array = _Py_CONTAINER_OF(items, _PyListArray, ob_item); + if (use_qsbr) { + _PyMem_FreeDelayed(array); + } + else { + PyMem_Free(array); + } +#else + PyMem_Free(items); +#endif +} + /* Ensure ob_item has room for at least newsize elements, and set * ob_size to newsize. If newsize > ob_size on entry, the content * of the new slots at exit is undefined heap trash; it's the caller's @@ -47,8 +91,7 @@ get_list_freelist(void) static int list_resize(PyListObject *self, Py_ssize_t newsize) { - PyObject **items; - size_t new_allocated, num_allocated_bytes; + size_t new_allocated, target_bytes; Py_ssize_t allocated = self->allocated; /* Bypass realloc() when a previous overallocation is large enough @@ -80,9 +123,34 @@ list_resize(PyListObject *self, Py_ssize_t newsize) if (newsize == 0) new_allocated = 0; + +#ifdef Py_GIL_DISABLED + _PyListArray *array = list_allocate_array(new_allocated); + if (array == NULL) { + PyErr_NoMemory(); + return -1; + } + PyObject **old_items = self->ob_item; + if (self->ob_item) { + if (new_allocated < (size_t)allocated) { + target_bytes = new_allocated * sizeof(PyObject*); + } + else { + target_bytes = allocated * sizeof(PyObject*); + } + memcpy(array->ob_item, self->ob_item, target_bytes); + } + _Py_atomic_store_ptr_release(&self->ob_item, &array->ob_item); + self->allocated = new_allocated; + Py_SET_SIZE(self, newsize); + if (old_items != NULL) { + free_list_items(old_items, _PyObject_GC_IS_SHARED(self)); + } +#else + PyObject **items; if (new_allocated <= (size_t)PY_SSIZE_T_MAX / sizeof(PyObject *)) { - num_allocated_bytes = new_allocated * sizeof(PyObject *); - items = (PyObject **)PyMem_Realloc(self->ob_item, num_allocated_bytes); + target_bytes = new_allocated * sizeof(PyObject *); + items = (PyObject **)PyMem_Realloc(self->ob_item, target_bytes); } else { // integer overflow @@ -95,12 +163,14 @@ list_resize(PyListObject *self, Py_ssize_t newsize) self->ob_item = items; Py_SET_SIZE(self, newsize); self->allocated = new_allocated; +#endif return 0; } static int list_preallocate_exact(PyListObject *self, Py_ssize_t size) { + PyObject **items; assert(self->ob_item == NULL); assert(size > 0); @@ -110,11 +180,20 @@ list_preallocate_exact(PyListObject *self, Py_ssize_t size) * allocated size up to the nearest even number. */ size = (size + 1) & ~(size_t)1; - PyObject **items = PyMem_New(PyObject*, size); +#ifdef Py_GIL_DISABLED + _PyListArray *array = list_allocate_array(size); + if (array == NULL) { + PyErr_NoMemory(); + return -1; + } + items = array->ob_item; +#else + items = PyMem_New(PyObject*, size); if (items == NULL) { PyErr_NoMemory(); return -1; } +#endif self->ob_item = items; self->allocated = size; return 0; @@ -178,7 +257,17 @@ PyList_New(Py_ssize_t size) op->ob_item = NULL; } else { +#ifdef Py_GIL_DISABLED + _PyListArray *array = list_allocate_array(size); + if (array == NULL) { + Py_DECREF(op); + return PyErr_NoMemory(); + } + memset(&array->ob_item, 0, size * sizeof(PyObject *)); + op->ob_item = array->ob_item; +#else op->ob_item = (PyObject **) PyMem_Calloc(size, sizeof(PyObject *)); +#endif if (op->ob_item == NULL) { Py_DECREF(op); return PyErr_NoMemory(); @@ -199,11 +288,20 @@ list_new_prealloc(Py_ssize_t size) return NULL; } assert(op->ob_item == NULL); +#ifdef Py_GIL_DISABLED + _PyListArray *array = list_allocate_array(size); + if (array == NULL) { + Py_DECREF(op); + return PyErr_NoMemory(); + } + op->ob_item = array->ob_item; +#else op->ob_item = PyMem_New(PyObject *, size); if (op->ob_item == NULL) { Py_DECREF(op); return PyErr_NoMemory(); } +#endif op->allocated = size; return (PyObject *) op; } @@ -268,7 +366,7 @@ list_get_item_ref(PyListObject *op, Py_ssize_t i) if (ob_item == NULL) { return NULL; } - Py_ssize_t cap = _Py_atomic_load_ssize_relaxed(&op->allocated); + Py_ssize_t cap = list_capacity(ob_item); assert(cap != -1 && cap >= size); if (!valid_index(i, cap)) { return NULL; @@ -438,7 +536,7 @@ list_dealloc(PyObject *self) while (--i >= 0) { Py_XDECREF(op->ob_item[i]); } - PyMem_Free(op->ob_item); + free_list_items(op->ob_item, false); } #ifdef WITH_FREELISTS struct _Py_list_freelist *list_freelist = get_list_freelist(); @@ -737,12 +835,7 @@ list_clear_impl(PyListObject *a, bool is_resize) #else bool use_qsbr = false; #endif - if (use_qsbr) { - _PyMem_FreeDelayed(items); - } - else { - PyMem_Free(items); - } + free_list_items(items, use_qsbr); // Note that there is no guarantee that the list is actually empty // at this point, because XDECREF may have populated it indirectly again! } @@ -2758,7 +2851,12 @@ keyfunc_fail: while (--i >= 0) { Py_XDECREF(final_ob_item[i]); } - PyMem_Free(final_ob_item); +#ifdef Py_GIL_DISABLED + bool use_qsbr = _PyObject_GC_IS_SHARED(self); +#else + bool use_qsbr = false; +#endif + free_list_items(final_ob_item, use_qsbr); } return Py_XNewRef(result); }