Skip to content

bpo-40521: Remove freelist from collections.deque() #21073

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Jun 23, 2020
Merged

bpo-40521: Remove freelist from collections.deque() #21073

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2020-06-23-06-09-59.bpo-40521.HUfxP7.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Remove freelist from collections.deque().
23 changes: 2 additions & 21 deletions Modules/_collectionsmodule.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
Expand All @@ -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 *
Expand Down