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gh-101659: Isolate "obmalloc" State to Each Interpreter (gh-101660)

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This is strictly about moving the "obmalloc" runtime state from
`_PyRuntimeState` to `PyInterpreterState`.  Doing so improves isolation
between interpreters, specifically most of the memory (incl. objects)
allocated for each interpreter's use.  This is important for a
per-interpreter GIL, but such isolation is valuable even without it.

FWIW, a per-interpreter obmalloc is the proverbial
canary-in-the-coalmine when it comes to the isolation of objects between
interpreters.  Any object that leaks (unintentionally) to another
interpreter is highly likely to cause a crash (on debug builds at
least).  That's a useful thing to know, relative to interpreter
isolation.
This commit is contained in:
Eric Snow 2023-04-24 17:23:57 -06:00 • committed by GitHub
parent 01be52e42e
commit df3173d28e
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GPG key ID: 4AEE18F83AFDEB23
20 changed files with 322 additions and 73 deletions
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27
Python/pylifecycle.c
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@ -547,11 +547,21 @@ pycore_init_runtime(_PyRuntimeState *runtime,
}
static void
static PyStatus
init_interp_settings(PyInterpreterState *interp, const _PyInterpreterConfig *config)
{
assert(interp->feature_flags == 0);
if (config->use_main_obmalloc) {
interp->feature_flags |= Py_RTFLAGS_USE_MAIN_OBMALLOC;
}
else if (!config->check_multi_interp_extensions) {
/* The reason: PyModuleDef.m_base.m_copy leaks objects between
interpreters. */
return _PyStatus_ERR("per-interpreter obmalloc does not support "
"single-phase init extension modules");
}
if (config->allow_fork) {
interp->feature_flags |= Py_RTFLAGS_FORK;
}
@ -570,6 +580,8 @@ init_interp_settings(PyInterpreterState *interp, const _PyInterpreterConfig *con
if (config->check_multi_interp_extensions) {
interp->feature_flags |= Py_RTFLAGS_MULTI_INTERP_EXTENSIONS;
}
return _PyStatus_OK();
}
@ -622,7 +634,10 @@ pycore_create_interpreter(_PyRuntimeState *runtime,
}
const _PyInterpreterConfig config = _PyInterpreterConfig_LEGACY_INIT;
init_interp_settings(interp, &config);
status = init_interp_settings(interp, &config);
if (_PyStatus_EXCEPTION(status)) {
return status;
}
PyThreadState *tstate = _PyThreadState_New(interp);
if (tstate == NULL) {
@ -1668,6 +1683,8 @@ finalize_interp_types(PyInterpreterState *interp)
_PyFloat_FiniType(interp);
_PyLong_FiniTypes(interp);
_PyThread_FiniType(interp);
// XXX fini collections module static types (_PyStaticType_Dealloc())
// XXX fini IO module static types (_PyStaticType_Dealloc())
_PyErr_FiniTypes(interp);
_PyTypes_FiniTypes(interp);
@ -1936,6 +1953,7 @@ Py_FinalizeEx(void)
}
_Py_FinalizeRefTotal(runtime);
#endif
_Py_FinalizeAllocatedBlocks(runtime);
#ifdef Py_TRACE_REFS
/* Display addresses (& refcnts) of all objects still alive.
@ -2036,7 +2054,10 @@ new_interpreter(PyThreadState **tstate_p, const _PyInterpreterConfig *config)
goto error;
}
init_interp_settings(interp, config);
status = init_interp_settings(interp, config);
if (_PyStatus_EXCEPTION(status)) {
goto error;
}
status = init_interp_create_gil(tstate);
if (_PyStatus_EXCEPTION(status)) {