From d60c12cf18bbebe5e98c938dd1ba0adee2644aa9 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Wed, 26 Mar 2025 06:52:20 -0400
Subject: [PATCH 01/17] gh-131757: allow lru_cache functions to execute
 concurrently

---
 Modules/_functoolsmodule.c | 82 ++++++++++++++++++++++++++------------
 1 file changed, 57 insertions(+), 25 deletions(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index f91fa9a7327a3d..86e5053c451495 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1195,14 +1195,13 @@ infinite_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwd
         Py_DECREF(key);
         return NULL;
     }
-    result = _PyDict_GetItem_KnownHash(self->cache, key, hash);
-    if (result) {
-        Py_INCREF(result);
+    int res = _PyDict_GetItemRef_KnownHash((PyDictObject *)self->cache, key, hash, &result);
+    if (res > 0) {
         self->hits++;
         Py_DECREF(key);
         return result;
     }
-    if (PyErr_Occurred()) {
+    if (res < 0) {
         Py_DECREF(key);
         return NULL;
     }
@@ -1281,37 +1280,45 @@ lru_cache_prepend_link(lru_cache_object *self, lru_list_elem *link)
    so that we know the cache is a consistent state.
  */
 
-static PyObject *
-bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds)
+static int
+bounded_lru_cache_wrapper_pre_call_lock_held(lru_cache_object *self, PyObject *args, PyObject *kwds,
+                                             PyObject **result, PyObject **key, Py_hash_t *hash)
 {
     lru_list_elem *link;
-    PyObject *key, *result, *testresult;
-    Py_hash_t hash;
 
-    key = lru_cache_make_key(self->kwd_mark, args, kwds, self->typed);
-    if (!key)
-        return NULL;
-    hash = PyObject_Hash(key);
-    if (hash == -1) {
-        Py_DECREF(key);
-        return NULL;
+    PyObject *_key = *key = lru_cache_make_key(self->kwd_mark, args, kwds, self->typed);
+    if (!_key)
+        return -1;
+    Py_hash_t _hash = *hash = PyObject_Hash(_key);
+    if (_hash == -1) {
+        Py_DECREF(_key);
+        return -1;
     }
-    link  = (lru_list_elem *)_PyDict_GetItem_KnownHash(self->cache, key, hash);
+    link = (lru_list_elem *)_PyDict_GetItem_KnownHash(self->cache, _key, _hash);
     if (link != NULL) {
         lru_cache_extract_link(link);
         lru_cache_append_link(self, link);
-        result = link->result;
+        *result = link->result;
         self->hits++;
-        Py_INCREF(result);
-        Py_DECREF(key);
-        return result;
+        Py_INCREF(link->result);
+        Py_DECREF(_key);
+        return 1;
     }
     if (PyErr_Occurred()) {
-        Py_DECREF(key);
-        return NULL;
+        Py_DECREF(_key);
+        return -1;
     }
     self->misses++;
-    result = PyObject_Call(self->func, args, kwds);
+    return 0;
+}
+
+PyObject *
+bounded_lru_cache_wrapper_post_call_lock_held(lru_cache_object *self,
+                                              PyObject *result, PyObject *key, Py_hash_t hash)
+{
+    lru_list_elem *link;
+    PyObject *testresult;
+
     if (!result) {
         Py_DECREF(key);
         return NULL;
@@ -1447,6 +1454,33 @@ bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds
     return result;
 }
 
+static PyObject *
+bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds)
+{
+    PyObject *key, *result;
+    Py_hash_t hash;
+    int res;
+
+    Py_BEGIN_CRITICAL_SECTION(self);
+    res = bounded_lru_cache_wrapper_pre_call_lock_held(self, args, kwds, &result, &key, &hash);
+    Py_END_CRITICAL_SECTION();
+
+    if (res < 0) {
+        return NULL;
+    }
+    if (res > 0) {
+        return result;
+    }
+
+    result = PyObject_Call(self->func, args, kwds);
+
+    Py_BEGIN_CRITICAL_SECTION(self);
+    result = bounded_lru_cache_wrapper_post_call_lock_held(self, result, key, hash);
+    Py_END_CRITICAL_SECTION();
+
+    return result;
+}
+
 static PyObject *
 lru_cache_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 {
@@ -1579,9 +1613,7 @@ lru_cache_call(PyObject *op, PyObject *args, PyObject *kwds)
 {
     lru_cache_object *self = lru_cache_object_CAST(op);
     PyObject *result;
-    Py_BEGIN_CRITICAL_SECTION(self);
     result = self->wrapper(self, args, kwds);
-    Py_END_CRITICAL_SECTION();
     return result;
 }
 

From 2dfcea3dbe2cc44e862dcf42146218fcdc2391f1 Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Wed, 26 Mar 2025 10:56:24 +0000
Subject: [PATCH 02/17] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20b?=
 =?UTF-8?q?lurb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst  | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst

diff --git a/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst b/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst
new file mode 100644
index 00000000000000..f4e8647961dc48
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst
@@ -0,0 +1 @@
+Make ``functools.lru_cache`` call the cached function unlocked to allow concurrency.

From c700d1ed6a7c28c6c13c10e40b2fb1a70586c84f Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Wed, 26 Mar 2025 07:01:58 -0400
Subject: [PATCH 03/17] fix smelly symbols

---
 Modules/_functoolsmodule.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 86e5053c451495..b78cf53a656aa9 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1286,26 +1286,26 @@ bounded_lru_cache_wrapper_pre_call_lock_held(lru_cache_object *self, PyObject *a
 {
     lru_list_elem *link;
 
-    PyObject *_key = *key = lru_cache_make_key(self->kwd_mark, args, kwds, self->typed);
-    if (!_key)
+    PyObject *key_ = *key = lru_cache_make_key(self->kwd_mark, args, kwds, self->typed);
+    if (!key_)
         return -1;
-    Py_hash_t _hash = *hash = PyObject_Hash(_key);
-    if (_hash == -1) {
-        Py_DECREF(_key);
+    Py_hash_t hash_ = *hash = PyObject_Hash(key_);
+    if (hash_ == -1) {
+        Py_DECREF(key_);
         return -1;
     }
-    link = (lru_list_elem *)_PyDict_GetItem_KnownHash(self->cache, _key, _hash);
+    link = (lru_list_elem *)_PyDict_GetItem_KnownHash(self->cache, key_, hash_);
     if (link != NULL) {
         lru_cache_extract_link(link);
         lru_cache_append_link(self, link);
         *result = link->result;
         self->hits++;
         Py_INCREF(link->result);
-        Py_DECREF(_key);
+        Py_DECREF(key_);
         return 1;
     }
     if (PyErr_Occurred()) {
-        Py_DECREF(_key);
+        Py_DECREF(key_);
         return -1;
     }
     self->misses++;

From 24d4f7a8beecf544cdadbbc3ffcc45e377de9b19 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Wed, 26 Mar 2025 07:10:56 -0400
Subject: [PATCH 04/17] fix smelly symbols for real this time

---
 Modules/_functoolsmodule.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index b78cf53a656aa9..d7d2d6912b1bae 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1312,7 +1312,7 @@ bounded_lru_cache_wrapper_pre_call_lock_held(lru_cache_object *self, PyObject *a
     return 0;
 }
 
-PyObject *
+static PyObject *
 bounded_lru_cache_wrapper_post_call_lock_held(lru_cache_object *self,
                                               PyObject *result, PyObject *key, Py_hash_t hash)
 {

From 7ead4eec0aff7bc20611a47e8ca541ca1fee8489 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Wed, 26 Mar 2025 13:31:21 -0400
Subject: [PATCH 05/17] requested changes

---
 Modules/_functoolsmodule.c | 42 ++++++++++++++++++++++++++++++--------
 1 file changed, 34 insertions(+), 8 deletions(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index d7d2d6912b1bae..f5972902b047d7 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -4,6 +4,7 @@
 #include "pycore_long.h"          // _PyLong_GetZero()
 #include "pycore_moduleobject.h"  // _PyModule_GetState()
 #include "pycore_object.h"        // _PyObject_GC_TRACK
+#include "pycore_pyatomic_ft_wrappers.h"
 #include "pycore_pystate.h"       // _PyThreadState_GET()
 #include "pycore_tuple.h"         // _PyTuple_ITEMS()
 
@@ -1175,7 +1176,11 @@ uncached_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwd
 {
     PyObject *result;
 
+#ifdef Py_GIL_DISABLED
+    _Py_atomic_add_ssize(&self->misses, 1);
+#else
     self->misses++;
+#endif
     result = PyObject_Call(self->func, args, kwds);
     if (!result)
         return NULL;
@@ -1197,7 +1202,11 @@ infinite_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwd
     }
     int res = _PyDict_GetItemRef_KnownHash((PyDictObject *)self->cache, key, hash, &result);
     if (res > 0) {
+#ifdef Py_GIL_DISABLED
+        _Py_atomic_add_ssize(&self->hits, 1);
+#else
         self->hits++;
+#endif
         Py_DECREF(key);
         return result;
     }
@@ -1205,7 +1214,11 @@ infinite_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwd
         Py_DECREF(key);
         return NULL;
     }
+#ifdef Py_GIL_DISABLED
+    _Py_atomic_add_ssize(&self->misses, 1);
+#else
     self->misses++;
+#endif
     result = PyObject_Call(self->func, args, kwds);
     if (!result) {
         Py_DECREF(key);
@@ -1281,8 +1294,8 @@ lru_cache_prepend_link(lru_cache_object *self, lru_list_elem *link)
  */
 
 static int
-bounded_lru_cache_wrapper_pre_call_lock_held(lru_cache_object *self, PyObject *args, PyObject *kwds,
-                                             PyObject **result, PyObject **key, Py_hash_t *hash)
+bounded_lru_cache_get_lock_held(lru_cache_object *self, PyObject *args, PyObject *kwds,
+                                PyObject **result, PyObject **key, Py_hash_t *hash)
 {
     lru_list_elem *link;
 
@@ -1299,7 +1312,11 @@ bounded_lru_cache_wrapper_pre_call_lock_held(lru_cache_object *self, PyObject *a
         lru_cache_extract_link(link);
         lru_cache_append_link(self, link);
         *result = link->result;
+#ifdef Py_GIL_DISABLED
+        _Py_atomic_add_ssize(&self->hits, 1);
+#else
         self->hits++;
+#endif
         Py_INCREF(link->result);
         Py_DECREF(key_);
         return 1;
@@ -1308,12 +1325,16 @@ bounded_lru_cache_wrapper_pre_call_lock_held(lru_cache_object *self, PyObject *a
         Py_DECREF(key_);
         return -1;
     }
+#ifdef Py_GIL_DISABLED
+    _Py_atomic_add_ssize(&self->misses, 1);
+#else
     self->misses++;
+#endif
     return 0;
 }
 
 static PyObject *
-bounded_lru_cache_wrapper_post_call_lock_held(lru_cache_object *self,
+bounded_lru_cache_update_lock_held(lru_cache_object *self,
                                               PyObject *result, PyObject *key, Py_hash_t hash)
 {
     lru_list_elem *link;
@@ -1462,7 +1483,7 @@ bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds
     int res;
 
     Py_BEGIN_CRITICAL_SECTION(self);
-    res = bounded_lru_cache_wrapper_pre_call_lock_held(self, args, kwds, &result, &key, &hash);
+    res = bounded_lru_cache_get_lock_held(self, args, kwds, &result, &key, &hash);
     Py_END_CRITICAL_SECTION();
 
     if (res < 0) {
@@ -1475,7 +1496,7 @@ bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds
     result = PyObject_Call(self->func, args, kwds);
 
     Py_BEGIN_CRITICAL_SECTION(self);
-    result = bounded_lru_cache_wrapper_post_call_lock_held(self, result, key, hash);
+    result = bounded_lru_cache_update_lock_held(self, result, key, hash);
     Py_END_CRITICAL_SECTION();
 
     return result;
@@ -1640,11 +1661,15 @@ _functools__lru_cache_wrapper_cache_info_impl(PyObject *self)
     lru_cache_object *_self = (lru_cache_object *) self;
     if (_self->maxsize == -1) {
         return PyObject_CallFunction(_self->cache_info_type, "nnOn",
-                                     _self->hits, _self->misses, Py_None,
+                                     FT_ATOMIC_LOAD_SSIZE_RELAXED(_self->hits),
+                                     FT_ATOMIC_LOAD_SSIZE_RELAXED(_self->misses),
+                                     Py_None,
                                      PyDict_GET_SIZE(_self->cache));
     }
     return PyObject_CallFunction(_self->cache_info_type, "nnnn",
-                                 _self->hits, _self->misses, _self->maxsize,
+                                 FT_ATOMIC_LOAD_SSIZE_RELAXED(_self->hits),
+                                 FT_ATOMIC_LOAD_SSIZE_RELAXED(_self->misses),
+                                 _self->maxsize,
                                  PyDict_GET_SIZE(_self->cache));
 }
 
@@ -1661,7 +1686,8 @@ _functools__lru_cache_wrapper_cache_clear_impl(PyObject *self)
 {
     lru_cache_object *_self = (lru_cache_object *) self;
     lru_list_elem *list = lru_cache_unlink_list(_self);
-    _self->hits = _self->misses = 0;
+    FT_ATOMIC_STORE_SSIZE_RELAXED(_self->hits, 0);
+    FT_ATOMIC_STORE_SSIZE_RELAXED(_self->misses, 0);
     PyDict_Clear(_self->cache);
     lru_cache_clear_list(list);
     Py_RETURN_NONE;

From 68d14eaee615ae8927d4cb82d65ed31535952005 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Wed, 26 Mar 2025 13:43:50 -0400
Subject: [PATCH 06/17] remove unnecessary atomics

---
 Modules/_functoolsmodule.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index f5972902b047d7..e909924cb9f34e 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1312,11 +1312,7 @@ bounded_lru_cache_get_lock_held(lru_cache_object *self, PyObject *args, PyObject
         lru_cache_extract_link(link);
         lru_cache_append_link(self, link);
         *result = link->result;
-#ifdef Py_GIL_DISABLED
-        _Py_atomic_add_ssize(&self->hits, 1);
-#else
         self->hits++;
-#endif
         Py_INCREF(link->result);
         Py_DECREF(key_);
         return 1;
@@ -1325,11 +1321,7 @@ bounded_lru_cache_get_lock_held(lru_cache_object *self, PyObject *args, PyObject
         Py_DECREF(key_);
         return -1;
     }
-#ifdef Py_GIL_DISABLED
-    _Py_atomic_add_ssize(&self->misses, 1);
-#else
     self->misses++;
-#endif
     return 0;
 }
 

From 028f18b69b4cb4bcf989df6cb6fc8ac3520937dc Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Wed, 26 Mar 2025 13:55:22 -0400
Subject: [PATCH 07/17] add FT_ATOMIC_ADD_SSIZE just in this file

---
 Modules/_functoolsmodule.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index e909924cb9f34e..1bb5044a37c852 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -41,6 +41,12 @@ get_functools_state(PyObject *module)
     return (_functools_state *)state;
 }
 
+#ifdef Py_GIL_DISABLED
+#define FT_ATOMIC_ADD_SSIZE(value, new_value) \
+    _Py_atomic_add_ssize(&value, new_value)
+#else
+#define FT_ATOMIC_ADD_SSIZE(value, new_value) value += new_value
+#endif
 
 /* partial object **********************************************************/
 
@@ -1176,11 +1182,7 @@ uncached_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwd
 {
     PyObject *result;
 
-#ifdef Py_GIL_DISABLED
-    _Py_atomic_add_ssize(&self->misses, 1);
-#else
-    self->misses++;
-#endif
+    FT_ATOMIC_ADD_SSIZE(self->misses, 1);
     result = PyObject_Call(self->func, args, kwds);
     if (!result)
         return NULL;
@@ -1202,11 +1204,7 @@ infinite_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwd
     }
     int res = _PyDict_GetItemRef_KnownHash((PyDictObject *)self->cache, key, hash, &result);
     if (res > 0) {
-#ifdef Py_GIL_DISABLED
-        _Py_atomic_add_ssize(&self->hits, 1);
-#else
-        self->hits++;
-#endif
+        FT_ATOMIC_ADD_SSIZE(self->hits, 1);
         Py_DECREF(key);
         return result;
     }
@@ -1214,11 +1212,7 @@ infinite_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwd
         Py_DECREF(key);
         return NULL;
     }
-#ifdef Py_GIL_DISABLED
-    _Py_atomic_add_ssize(&self->misses, 1);
-#else
-    self->misses++;
-#endif
+    FT_ATOMIC_ADD_SSIZE(self->misses, 1);
     result = PyObject_Call(self->func, args, kwds);
     if (!result) {
         Py_DECREF(key);

From 6c74b262cd6484093f4f3e6aa1344cf4a9a60430 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Wed, 26 Mar 2025 14:20:11 -0400
Subject: [PATCH 08/17] _PyDict_GetItemRef_KnownHash_LockHeld()

---
 Modules/_functoolsmodule.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 1bb5044a37c852..679001b1fbe277 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1301,17 +1301,19 @@ bounded_lru_cache_get_lock_held(lru_cache_object *self, PyObject *args, PyObject
         Py_DECREF(key_);
         return -1;
     }
-    link = (lru_list_elem *)_PyDict_GetItem_KnownHash(self->cache, key_, hash_);
-    if (link != NULL) {
+    int res = _PyDict_GetItemRef_KnownHash_LockHeld((PyDictObject *)self->cache, key_, hash_,
+                                                    (PyObject **)&link);
+    if (res > 0) {
         lru_cache_extract_link(link);
         lru_cache_append_link(self, link);
         *result = link->result;
         self->hits++;
         Py_INCREF(link->result);
+        Py_DECREF(link);
         Py_DECREF(key_);
         return 1;
     }
-    if (PyErr_Occurred()) {
+    if (res < 0) {
         Py_DECREF(key_);
         return -1;
     }
@@ -1325,20 +1327,23 @@ bounded_lru_cache_update_lock_held(lru_cache_object *self,
 {
     lru_list_elem *link;
     PyObject *testresult;
+    int res;
 
     if (!result) {
         Py_DECREF(key);
         return NULL;
     }
-    testresult = _PyDict_GetItem_KnownHash(self->cache, key, hash);
-    if (testresult != NULL) {
+    res = _PyDict_GetItemRef_KnownHash_LockHeld((PyDictObject *)self->cache, key, hash,
+                                                &testresult);
+    if (res > 0) {
         /* Getting here means that this same key was added to the cache
            during the PyObject_Call().  Since the link update is already
            done, we need only return the computed result. */
+        Py_DECREF(testresult);
         Py_DECREF(key);
         return result;
     }
-    if (PyErr_Occurred()) {
+    if (res < 0) {
         /* This is an unusual case since this same lookup
            did not previously trigger an error during lookup.
            Treat it the same as an error in user function
@@ -1402,7 +1407,7 @@ bounded_lru_cache_update_lock_held(lru_cache_object *self,
        The cache dict holds one reference to the link.
        We created one other reference when the link was created.
        The linked list only has borrowed references. */
-    int res = _PyDict_Pop_KnownHash((PyDictObject*)self->cache, link->key,
+    res = _PyDict_Pop_KnownHash((PyDictObject*)self->cache, link->key,
                                     link->hash, &popresult);
     if (res < 0) {
         /* An error arose while trying to remove the oldest key (the one

From 2910429b6c3bf64be211b2851be8b386d29c0429 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Thu, 27 Mar 2025 08:49:08 -0400
Subject: [PATCH 09/17] requested changes

---
 .../2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst       | 2 +-
 Modules/_functoolsmodule.c                               | 9 +++++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst b/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst
index f4e8647961dc48..440239160cbe2a 100644
--- a/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst
+++ b/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst
@@ -1 +1 @@
-Make ``functools.lru_cache`` call the cached function unlocked to allow concurrency.
+Make :func:``functools.lru_cache`` call the cached function unlocked to allow concurrency.
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 679001b1fbe277..7f3b3bda8a3d94 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1291,6 +1291,7 @@ static int
 bounded_lru_cache_get_lock_held(lru_cache_object *self, PyObject *args, PyObject *kwds,
                                 PyObject **result, PyObject **key, Py_hash_t *hash)
 {
+    _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(self);
     lru_list_elem *link;
 
     PyObject *key_ = *key = lru_cache_make_key(self->kwd_mark, args, kwds, self->typed);
@@ -1298,7 +1299,7 @@ bounded_lru_cache_get_lock_held(lru_cache_object *self, PyObject *args, PyObject
         return -1;
     Py_hash_t hash_ = *hash = PyObject_Hash(key_);
     if (hash_ == -1) {
-        Py_DECREF(key_);
+        Py_DECREF(key_);  /* dead reference left in *key, is not used */
         return -1;
     }
     int res = _PyDict_GetItemRef_KnownHash_LockHeld((PyDictObject *)self->cache, key_, hash_,
@@ -1323,8 +1324,9 @@ bounded_lru_cache_get_lock_held(lru_cache_object *self, PyObject *args, PyObject
 
 static PyObject *
 bounded_lru_cache_update_lock_held(lru_cache_object *self,
-                                              PyObject *result, PyObject *key, Py_hash_t hash)
+                                   PyObject *result, PyObject *key, Py_hash_t hash)
 {
+    _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(self);
     lru_list_elem *link;
     PyObject *testresult;
     int res;
@@ -1487,6 +1489,9 @@ bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds
     result = PyObject_Call(self->func, args, kwds);
 
     Py_BEGIN_CRITICAL_SECTION(self);
+    /* Note:  key will be released in the below function and
+       result may be relased on error, or returned as a passthrough
+       or have its reference count increased if is added to cache. */
     result = bounded_lru_cache_update_lock_held(self, result, key, hash);
     Py_END_CRITICAL_SECTION();
 

From 12823257ae1152954f1c76ae0903c336a0764113 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Thu, 27 Mar 2025 08:50:50 -0400
Subject: [PATCH 10/17] stupid news

---
 .../next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst b/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst
index 440239160cbe2a..89f71ca113aa3d 100644
--- a/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst
+++ b/Misc/NEWS.d/next/Library/2025-03-26-10-56-22.gh-issue-131757.pFRdmN.rst
@@ -1 +1 @@
-Make :func:``functools.lru_cache`` call the cached function unlocked to allow concurrency.
+Make :func:`functools.lru_cache` call the cached function unlocked to allow concurrency.

From 34f7fe7d3e46506b4d670b8712573b9c20c3999b Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Thu, 27 Mar 2025 09:04:34 -0400
Subject: [PATCH 11/17] requested changes

---
 Modules/_functoolsmodule.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 7f3b3bda8a3d94..285960fbe6c735 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1489,9 +1489,10 @@ bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds
     result = PyObject_Call(self->func, args, kwds);
 
     Py_BEGIN_CRITICAL_SECTION(self);
-    /* Note:  key will be released in the below function and
-       result may be relased on error, or returned as a passthrough
-       or have its reference count increased if is added to cache. */
+    /* Note:  key will be stolen in the below function, and
+       result may be stolen or sometimes re-returned as a passthrough.
+       Treat both as being stolen.
+     */
     result = bounded_lru_cache_update_lock_held(self, result, key, hash);
     Py_END_CRITICAL_SECTION();
 

From 60a475dbe481b8bc125b0a21714c48beb76cf5df Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Fri, 28 Mar 2025 12:05:54 -0400
Subject: [PATCH 12/17] FT_ATOMIC_ADD_SSIZE into pyatomic_ft_wrappers.h

---
 Include/internal/pycore_pyatomic_ft_wrappers.h | 3 +++
 Modules/_functoolsmodule.c                     | 7 -------
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/Include/internal/pycore_pyatomic_ft_wrappers.h b/Include/internal/pycore_pyatomic_ft_wrappers.h
index d755d03a5fa190..c99085fcdd2fb0 100644
--- a/Include/internal/pycore_pyatomic_ft_wrappers.h
+++ b/Include/internal/pycore_pyatomic_ft_wrappers.h
@@ -109,6 +109,8 @@ extern "C" {
     _Py_atomic_store_ullong_relaxed(&value, new_value)
 #define FT_ATOMIC_LOAD_ULLONG_RELAXED(value) \
     _Py_atomic_load_ullong_relaxed(&value)
+#define FT_ATOMIC_ADD_SSIZE(value, new_value) \
+    _Py_atomic_add_ssize(&value, new_value)
 
 #else
 #define FT_ATOMIC_LOAD_PTR(value) value
@@ -156,6 +158,7 @@ extern "C" {
 #define FT_ATOMIC_STORE_LLONG_RELAXED(value, new_value) value = new_value
 #define FT_ATOMIC_LOAD_ULLONG_RELAXED(value) value
 #define FT_ATOMIC_STORE_ULLONG_RELAXED(value, new_value) value = new_value
+#define FT_ATOMIC_ADD_SSIZE(value, new_value) (value += new_value) - new_value
 
 #endif
 
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 285960fbe6c735..c91d0c7a422eee 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -41,13 +41,6 @@ get_functools_state(PyObject *module)
     return (_functools_state *)state;
 }
 
-#ifdef Py_GIL_DISABLED
-#define FT_ATOMIC_ADD_SSIZE(value, new_value) \
-    _Py_atomic_add_ssize(&value, new_value)
-#else
-#define FT_ATOMIC_ADD_SSIZE(value, new_value) value += new_value
-#endif
-
 /* partial object **********************************************************/
 
 

From 4200582082eee25a442d7ba2ac000d6be0607035 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Fri, 28 Mar 2025 12:18:47 -0400
Subject: [PATCH 13/17] stupid warnings

---
 Include/internal/pycore_pyatomic_ft_wrappers.h | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Include/internal/pycore_pyatomic_ft_wrappers.h b/Include/internal/pycore_pyatomic_ft_wrappers.h
index c99085fcdd2fb0..c5ee1b6f79330d 100644
--- a/Include/internal/pycore_pyatomic_ft_wrappers.h
+++ b/Include/internal/pycore_pyatomic_ft_wrappers.h
@@ -158,7 +158,14 @@ extern "C" {
 #define FT_ATOMIC_STORE_LLONG_RELAXED(value, new_value) value = new_value
 #define FT_ATOMIC_LOAD_ULLONG_RELAXED(value) value
 #define FT_ATOMIC_STORE_ULLONG_RELAXED(value, new_value) value = new_value
-#define FT_ATOMIC_ADD_SSIZE(value, new_value) (value += new_value) - new_value
+
+static inline _FT_ATOMIC_ADD_SSIZE(Py_ssize_t *value, Py_ssize_t new_value)
+{
+    Py_ssize_t old_value = *value;
+    *value = old_value + new_value;
+    return old_value;
+}
+#define FT_ATOMIC_ADD_SSIZE(value, new_value) _FT_ATOMIC_ADD_SSIZE(&value, new_value)
 
 #endif
 

From aed9b452fb0383c5bc37673468f0f4d01eff7873 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Fri, 28 Mar 2025 12:21:36 -0400
Subject: [PATCH 14/17] return type

---
 Include/internal/pycore_pyatomic_ft_wrappers.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Include/internal/pycore_pyatomic_ft_wrappers.h b/Include/internal/pycore_pyatomic_ft_wrappers.h
index c5ee1b6f79330d..99466dd810c7a5 100644
--- a/Include/internal/pycore_pyatomic_ft_wrappers.h
+++ b/Include/internal/pycore_pyatomic_ft_wrappers.h
@@ -159,7 +159,8 @@ extern "C" {
 #define FT_ATOMIC_LOAD_ULLONG_RELAXED(value) value
 #define FT_ATOMIC_STORE_ULLONG_RELAXED(value, new_value) value = new_value
 
-static inline _FT_ATOMIC_ADD_SSIZE(Py_ssize_t *value, Py_ssize_t new_value)
+static inline Py_ssize_t
+_FT_ATOMIC_ADD_SSIZE(Py_ssize_t *value, Py_ssize_t new_value)
 {
     Py_ssize_t old_value = *value;
     *value = old_value + new_value;

From 47e47d58640b9b53e1ed46db453cd29732180a78 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Fri, 28 Mar 2025 12:27:59 -0400
Subject: [PATCH 15/17] FT_ATOMIC_ADD_SSIZE no return value

---
 Include/internal/pycore_pyatomic_ft_wrappers.h | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/Include/internal/pycore_pyatomic_ft_wrappers.h b/Include/internal/pycore_pyatomic_ft_wrappers.h
index 99466dd810c7a5..3e41e2fd1569ca 100644
--- a/Include/internal/pycore_pyatomic_ft_wrappers.h
+++ b/Include/internal/pycore_pyatomic_ft_wrappers.h
@@ -110,7 +110,7 @@ extern "C" {
 #define FT_ATOMIC_LOAD_ULLONG_RELAXED(value) \
     _Py_atomic_load_ullong_relaxed(&value)
 #define FT_ATOMIC_ADD_SSIZE(value, new_value) \
-    _Py_atomic_add_ssize(&value, new_value)
+    (void)_Py_atomic_add_ssize(&value, new_value)
 
 #else
 #define FT_ATOMIC_LOAD_PTR(value) value
@@ -158,15 +158,7 @@ extern "C" {
 #define FT_ATOMIC_STORE_LLONG_RELAXED(value, new_value) value = new_value
 #define FT_ATOMIC_LOAD_ULLONG_RELAXED(value) value
 #define FT_ATOMIC_STORE_ULLONG_RELAXED(value, new_value) value = new_value
-
-static inline Py_ssize_t
-_FT_ATOMIC_ADD_SSIZE(Py_ssize_t *value, Py_ssize_t new_value)
-{
-    Py_ssize_t old_value = *value;
-    *value = old_value + new_value;
-    return old_value;
-}
-#define FT_ATOMIC_ADD_SSIZE(value, new_value) _FT_ATOMIC_ADD_SSIZE(&value, new_value)
+#define FT_ATOMIC_ADD_SSIZE(value, new_value) (void)(value += new_value)
 
 #endif
 

From 11eab6d046633128f46e550465e42f301958dd67 Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Mon, 14 Apr 2025 08:39:51 -0400
Subject: [PATCH 16/17] bounded_lru_cache_get_lock_held atomic writes so tsan
 doesn't complain

---
 Modules/_functoolsmodule.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 634539ea713497..9603344f868cc4 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1299,7 +1299,7 @@ bounded_lru_cache_get_lock_held(lru_cache_object *self, PyObject *args, PyObject
         lru_cache_extract_link(link);
         lru_cache_append_link(self, link);
         *result = link->result;
-        self->hits++;
+        FT_ATOMIC_ADD_SSIZE(self->hits, 1);
         Py_INCREF(link->result);
         Py_DECREF(link);
         Py_DECREF(key_);
@@ -1309,7 +1309,7 @@ bounded_lru_cache_get_lock_held(lru_cache_object *self, PyObject *args, PyObject
         Py_DECREF(key_);
         return -1;
     }
-    self->misses++;
+    FT_ATOMIC_ADD_SSIZE(self->misses, 1);
     return 0;
 }
 

From 5d1bf312dd62baf1a91ef8eed7b80fc86f50380f Mon Sep 17 00:00:00 2001
From: Tomasz Pytel <tompytel@gmail.com>
Date: Mon, 14 Apr 2025 11:07:59 -0400
Subject: [PATCH 17/17] fix indentation

---
 Modules/_functoolsmodule.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 9603344f868cc4..e6c454faf4b16f 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1016,7 +1016,7 @@ _functools_reduce_impl(PyObject *module, PyObject *func, PyObject *seq,
 
     if (result == NULL)
         PyErr_SetString(PyExc_TypeError,
-                   "reduce() of empty iterable with no initial value");
+                        "reduce() of empty iterable with no initial value");
 
     Py_DECREF(it);
     return result;
@@ -1401,7 +1401,7 @@ bounded_lru_cache_update_lock_held(lru_cache_object *self,
        We created one other reference when the link was created.
        The linked list only has borrowed references. */
     res = _PyDict_Pop_KnownHash((PyDictObject*)self->cache, link->key,
-                                    link->hash, &popresult);
+                                link->hash, &popresult);
     if (res < 0) {
         /* An error arose while trying to remove the oldest key (the one
            being evicted) from the cache.  We restore the link to its