https://github.com/python/cpython/commit/31633f4473966b3bcd470440bab7f348711be48f
commit: 31633f4473966b3bcd470440bab7f348711be48f
branch: main
author: Sam Gross <[email protected]>
committer: colesbury <[email protected]>
date: 2024-02-09T09:23:12-05:00
summary:
gh-115184: Fix refleak tracking issues in free-threaded build (#115188)
Fixes a few issues related to refleak tracking in the free-threaded build:
- Count blocks in abandoned segments
- Call `_mi_page_free_collect` earlier during heap traversal in order to get an
accurate count of blocks in use.
- Add missing refcount tracking in `_Py_DecRefSharedDebug` and
`_Py_ExplicitMergeRefcount`.
- Pause threads in `get_num_global_allocated_blocks` to ensure that traversing
the mimalloc heaps is safe.
files:
M Objects/mimalloc/heap.c
M Objects/object.c
M Objects/obmalloc.c
diff --git a/Objects/mimalloc/heap.c b/Objects/mimalloc/heap.c
index 164b28f0fab240..154dad0b128480 100644
--- a/Objects/mimalloc/heap.c
+++ b/Objects/mimalloc/heap.c
@@ -538,7 +538,6 @@ bool _mi_heap_area_visit_blocks(const mi_heap_area_t* area,
mi_page_t *page, mi_
mi_assert(page != NULL);
if (page == NULL) return true;
- _mi_page_free_collect(page,true);
mi_assert_internal(page->local_free == NULL);
if (page->used == 0) return true;
@@ -635,6 +634,7 @@ bool _mi_heap_area_visit_blocks(const mi_heap_area_t* area,
mi_page_t *page, mi_
typedef bool (mi_heap_area_visit_fun)(const mi_heap_t* heap, const
mi_heap_area_ex_t* area, void* arg);
void _mi_heap_area_init(mi_heap_area_t* area, mi_page_t* page) {
+ _mi_page_free_collect(page,true);
const size_t bsize = mi_page_block_size(page);
const size_t ubsize = mi_page_usable_block_size(page);
area->reserved = page->reserved * bsize;
diff --git a/Objects/object.c b/Objects/object.c
index bbf7f98ae3daf9..37a4b7a417e35f 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -346,6 +346,9 @@ _Py_DecRefSharedDebug(PyObject *o, const char *filename,
int lineno)
if (should_queue) {
// TODO: the inter-thread queue is not yet implemented. For now,
// we just merge the refcount here.
+#ifdef Py_REF_DEBUG
+ _Py_IncRefTotal(_PyInterpreterState_GET());
+#endif
Py_ssize_t refcount = _Py_ExplicitMergeRefcount(o, -1);
if (refcount == 0) {
_Py_Dealloc(o);
@@ -399,10 +402,6 @@ _Py_ExplicitMergeRefcount(PyObject *op, Py_ssize_t extra)
Py_ssize_t shared = _Py_atomic_load_ssize_relaxed(&op->ob_ref_shared);
do {
refcnt = Py_ARITHMETIC_RIGHT_SHIFT(Py_ssize_t, shared,
_Py_REF_SHARED_SHIFT);
- if (_Py_REF_IS_MERGED(shared)) {
- return refcnt;
- }
-
refcnt += (Py_ssize_t)op->ob_ref_local;
refcnt += extra;
@@ -410,6 +409,10 @@ _Py_ExplicitMergeRefcount(PyObject *op, Py_ssize_t extra)
} while (!_Py_atomic_compare_exchange_ssize(&op->ob_ref_shared,
&shared, new_shared));
+#ifdef Py_REF_DEBUG
+ _Py_AddRefTotal(_PyInterpreterState_GET(), extra);
+#endif
+
_Py_atomic_store_uint32_relaxed(&op->ob_ref_local, 0);
_Py_atomic_store_uintptr_relaxed(&op->ob_tid, 0);
return refcnt;
diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c
index bea4ea85332bdd..6a12c3dca38b36 100644
--- a/Objects/obmalloc.c
+++ b/Objects/obmalloc.c
@@ -1073,7 +1073,12 @@ get_mimalloc_allocated_blocks(PyInterpreterState *interp)
mi_heap_visit_blocks(heap, false, &count_blocks,
&allocated_blocks);
}
}
- // TODO(sgross): count blocks in abandoned segments.
+
+ mi_abandoned_pool_t *pool = &interp->mimalloc.abandoned_pool;
+ for (uint8_t tag = 0; tag < _Py_MIMALLOC_HEAP_COUNT; tag++) {
+ _mi_abandoned_pool_visit_blocks(pool, tag, false, &count_blocks,
+ &allocated_blocks);
+ }
#else
// TODO(sgross): this only counts the current thread's blocks.
mi_heap_t *heap = mi_heap_get_default();
@@ -1189,6 +1194,7 @@ get_num_global_allocated_blocks(_PyRuntimeState *runtime)
}
}
else {
+ _PyEval_StopTheWorldAll(&_PyRuntime);
HEAD_LOCK(runtime);
PyInterpreterState *interp = PyInterpreterState_Head();
assert(interp != NULL);
@@ -1208,6 +1214,7 @@ get_num_global_allocated_blocks(_PyRuntimeState *runtime)
}
}
HEAD_UNLOCK(runtime);
+ _PyEval_StartTheWorldAll(&_PyRuntime);
#ifdef Py_DEBUG
assert(got_main);
#endif
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