bpo-39984: Move pending calls to PyInterpreterState (GH-19066)

If Py_AddPendingCall() is called in a subinterpreter, the function is
now scheduled to be called from the subinterpreter, rather than being
called from the main interpreter.

Each subinterpreter now has its own list of scheduled calls.

* Move pending and eval_breaker fields from _PyRuntimeState.ceval
  to PyInterpreterState.ceval.
* new_interpreter() now calls _PyEval_InitThreads() to create
  pending calls lock.
* Fix Py_AddPendingCall() for subinterpreters. It now calls
  _PyThreadState_GET() which works in a subinterpreter if the
  caller holds the GIL, and only falls back on
  PyGILState_GetThisThreadState() if _PyThreadState_GET()
  returns NULL.

1 files changed, 4 insertions, 4 deletions

diff --git a/Include/internal/pycore_pystate.h b/Include/internal/pycore_pystate.h
index 0e3a9e6..92eeac7 100644
--- a/Include/internal/pycore_pystate.h
+++ b/Include/internal/pycore_pystate.h
@@ -35,12 +35,8 @@ struct _pending_calls {
 
 struct _ceval_runtime_state {
     int recursion_limit;
-    /* This single variable consolidates all requests to break out of
-       the fast path in the eval loop. */
-    _Py_atomic_int eval_breaker;
     /* Request for dropping the GIL */
     _Py_atomic_int gil_drop_request;
-    struct _pending_calls pending;
     /* Request for checking signals. */
     _Py_atomic_int signals_pending;
     struct _gil_runtime_state gil;
@@ -53,6 +49,10 @@ struct _ceval_state {
        c_tracefunc.  This speeds up the if statement in
        _PyEval_EvalFrameDefault() after fast_next_opcode. */
     int tracing_possible;
+    /* This single variable consolidates all requests to break out of
+       the fast path in the eval loop. */
+    _Py_atomic_int eval_breaker;
+    struct _pending_calls pending;
 };
 
 /* interpreter state */