gh-97922: Run the GC only on eval breaker (#97920)

1 files changed, 20 insertions, 10 deletions

diff --git a/Python/ceval_gil.c b/Python/ceval_gil.c
index fd737b5..9b9d7dc 100644
--- a/Python/ceval_gil.c
+++ b/Python/ceval_gil.c
@@ -5,6 +5,7 @@
 #include "pycore_pyerrors.h"      // _PyErr_Fetch()
 #include "pycore_pylifecycle.h"   // _PyErr_Print()
 #include "pycore_initconfig.h"    // _PyStatus_OK()
+#include "pycore_interp.h"        // _Py_RunGC()
 #include "pycore_pymem.h"         // _PyMem_IsPtrFreed()
 
 /*
@@ -69,7 +70,8 @@ COMPUTE_EVAL_BREAKER(PyInterpreterState *interp,
            && _Py_ThreadCanHandleSignals(interp))
         | (_Py_atomic_load_relaxed_int32(&ceval2->pending.calls_to_do)
            && _Py_ThreadCanHandlePendingCalls())
-        | ceval2->pending.async_exc);
+        | ceval2->pending.async_exc
+        | _Py_atomic_load_relaxed_int32(&ceval2->gc_scheduled));
 }
 
 
@@ -938,6 +940,7 @@ _Py_HandlePending(PyThreadState *tstate)
 {
     _PyRuntimeState * const runtime = &_PyRuntime;
     struct _ceval_runtime_state *ceval = &runtime->ceval;
+    struct _ceval_state *interp_ceval_state = &tstate->interp->ceval;
 
     /* Pending signals */
     if (_Py_atomic_load_relaxed_int32(&ceval->signals_pending)) {
@@ -947,20 +950,26 @@ _Py_HandlePending(PyThreadState *tstate)
     }
 
     /* Pending calls */
-    struct _ceval_state *ceval2 = &tstate->interp->ceval;
-    if (_Py_atomic_load_relaxed_int32(&ceval2->pending.calls_to_do)) {
+    if (_Py_atomic_load_relaxed_int32(&interp_ceval_state->pending.calls_to_do)) {
         if (make_pending_calls(tstate->interp) != 0) {
             return -1;
         }
     }
 
+    /* GC scheduled to run */
+    if (_Py_atomic_load_relaxed_int32(&interp_ceval_state->gc_scheduled)) {
+        _Py_atomic_store_relaxed(&interp_ceval_state->gc_scheduled, 0);
+        COMPUTE_EVAL_BREAKER(tstate->interp, ceval, interp_ceval_state);
+        _Py_RunGC(tstate);
+    }
+
     /* GIL drop request */
-    if (_Py_atomic_load_relaxed_int32(&ceval2->gil_drop_request)) {
+    if (_Py_atomic_load_relaxed_int32(&interp_ceval_state->gil_drop_request)) {
         /* Give another thread a chance */
         if (_PyThreadState_Swap(&runtime->gilstate, NULL) != tstate) {
             Py_FatalError("tstate mix-up");
         }
-        drop_gil(ceval, ceval2, tstate);
+        drop_gil(ceval, interp_ceval_state, tstate);
 
         /* Other threads may run now */
 
@@ -981,16 +990,17 @@ _Py_HandlePending(PyThreadState *tstate)
         return -1;
     }
 
-#ifdef MS_WINDOWS
-    // bpo-42296: On Windows, _PyEval_SignalReceived() can be called in a
-    // different thread than the Python thread, in which case
+
+    // It is possible that some of the conditions that trigger the eval breaker
+    // are called in a different thread than the Python thread. An example of
+    // this is bpo-42296: On Windows, _PyEval_SignalReceived() can be called in
+    // a different thread than the Python thread, in which case
     // _Py_ThreadCanHandleSignals() is wrong. Recompute eval_breaker in the
     // current Python thread with the correct _Py_ThreadCanHandleSignals()
     // value. It prevents to interrupt the eval loop at every instruction if
     // the current Python thread cannot handle signals (if
     // _Py_ThreadCanHandleSignals() is false).
-    COMPUTE_EVAL_BREAKER(tstate->interp, ceval, ceval2);
-#endif
+    COMPUTE_EVAL_BREAKER(tstate->interp, ceval, interp_ceval_state);
 
     return 0;
 }