[Python-checkins] bpo-40521: Remove freelist from collections.deque() (GH-21073)
Raymond Hettinger
webhook-mailer at python.org
Tue Jun 23 09:50:24 EDT 2020
https://github.com/python/cpython/commit/32f2eda85957365d208f499b730d30b7eb419741
commit: 32f2eda85957365d208f499b730d30b7eb419741
branch: master
author: Raymond Hettinger <rhettinger at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2020-06-23T06:50:15-07:00
summary:
bpo-40521: Remove freelist from collections.deque() (GH-21073)
files:
A Misc/NEWS.d/next/Library/2020-06-23-06-09-59.bpo-40521.HUfxP7.rst
M Modules/_collectionsmodule.c
diff --git a/Misc/NEWS.d/next/Library/2020-06-23-06-09-59.bpo-40521.HUfxP7.rst b/Misc/NEWS.d/next/Library/2020-06-23-06-09-59.bpo-40521.HUfxP7.rst
new file mode 100644
index 0000000000000..7689a1470b034
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-06-23-06-09-59.bpo-40521.HUfxP7.rst
@@ -0,0 +1 @@
+Remove freelist from collections.deque().
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 7120e4dda0ed2..00198ff3eb7dd 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -117,23 +117,9 @@ static PyTypeObject deque_type;
#define CHECK_NOT_END(link)
#endif
-/* A simple freelisting scheme is used to minimize calls to the memory
- allocator. It accommodates common use cases where new blocks are being
- added at about the same rate as old blocks are being freed.
- */
-
-#define MAXFREEBLOCKS 16
-static Py_ssize_t numfreeblocks = 0;
-static block *freeblocks[MAXFREEBLOCKS];
-
static block *
newblock(void) {
- block *b;
- if (numfreeblocks) {
- numfreeblocks--;
- return freeblocks[numfreeblocks];
- }
- b = PyMem_Malloc(sizeof(block));
+ block *b = PyMem_Malloc(sizeof(block));
if (b != NULL) {
return b;
}
@@ -144,12 +130,7 @@ newblock(void) {
static void
freeblock(block *b)
{
- if (numfreeblocks < MAXFREEBLOCKS) {
- freeblocks[numfreeblocks] = b;
- numfreeblocks++;
- } else {
- PyMem_Free(b);
- }
+ PyMem_Free(b);
}
static PyObject *
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