tracemalloc_alloc(), tracemalloc_realloc(), tracemalloc_free(),
_PyTraceMalloc_TraceRef() and _PyTraceMalloc_GetMemory() now check
'tracemalloc_config.tracing' after calling TABLES_LOCK().
_PyTraceMalloc_TraceRef() now always returns 0.
* Use TABLES_LOCK() to protect 'tracemalloc_config.tracing'.
* Hold TABLES_LOCK() longer while accessing tables.
* tracemalloc_realloc() and tracemalloc_free() no longer
remove the trace on reentrant call.
* _PyTraceMalloc_Stop() unregisters _PyTraceMalloc_TraceRef().
* _PyTraceMalloc_GetTraces() sets the reentrant flag.
* tracemalloc_clear_traces_unlocked() sets the reentrant flag.
Use a `_PyStackRef` and defer the reference to `f_executable` when
possible. This avoids some reference count contention in the common case
of executing the same code object from multiple threads concurrently in
the free-threaded build.
The tracemalloc_tracebacks hash table has traceback keys and NULL
values, but its destructors do not reflect this -- key_destroy_func is
NULL while value_destroy_func is raw_free. Swap these to free the
traceback keys instead.
* Add table describing possible executable classes for out-of-process debuggers.
* Remove shim code object creation code as it is no longer needed.
* Make lltrace a bit more robust w.r.t. non-standard frames.
Victor Stinner