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Argument Clinic: Add support for PEP 703's critical sections (Py_BEGIN_CRITICAL_SECTION()) #111903
Description
Feature or enhancement
PEP 703 in large part relies on replacing the GIL with fine grained per-object locks. The primary way to acquire and release these locks is through the critical section API (#111569). It would be helpful if argument clinic could auto generate the API calls in the binding code when specified.
For example, the bufferedio.c will require per-object locking around most calls for thread-safety in --disable-gil builds.
As an example, the _io._Buffered.close function is written as:
cpython/Modules/_io/bufferedio.c
Lines 523 to 529 in 6f09f69
We might add a @critical_section directive to designate that argument clinic should generate Py_BEGIN_CRITICAL_SECTION() and Py_END_CRITICAL_SECTION() in the binding code before calling _io__Buffered_close_impl.
/*[clinic input]
@critical_section
_io._Buffered.close
[clinic start generated code]*/
static PyObject *
_io__Buffered_close_impl(buffered *self)
/*[clinic end generated code: output=7280b7b42033be0c input=d20b83d1ddd7d805]*/The generated binding code in bufferedio.c.h would then look like:
static PyObject *
_io__Buffered_close(buffered *self, PyObject *Py_UNUSED(ignored))
{
PyObject *return_value = NULL;
Py_BEGIN_CRITICAL_SECTION(self);
return_value = _io__Buffered_close_impl(self);
Py_END_CRITICAL_SECTION();
return return_value;
}Note that Py_BEGIN/END_CRITICAL_SECTION() are no-ops in the default build.
Activity
corona10 commentedon Nov 9, 2023
cc @erlend-aasland
colesbury commentedon Nov 9, 2023
I've updated the issue to use AC's existing "directive" feature and syntax.
pythongh-111903: Add `@critical_section` directive to Argument Clinic.
Add "how to" for the critical_section Argument Clinic directive.
gh-111903: Add `@critical_section` directive to Argument Clinic. (#11…
Add "how to" for the critical_section Argument Clinic directive. (#1217)
pythongh-111903: Update AC to support "pycore_critical_section.h" header
pythongh-111903: Update AC to support "pycore_critical_section.h" header
gh-111903: Update AC to support "pycore_critical_section.h" header (g…
pythongh-111903: Add `@critical_section` directive to Argument Clinic. (
pythongh-111903: Update AC to support "pycore_critical_section.h" hea…
pythongh-111903: Add `@critical_section` directive to Argument Clinic. (
pythongh-111903: Update AC to support "pycore_critical_section.h" hea…