Add Py_GetConstant() and Py_GetConstantBorrowed() functions.
In the limited C API version 3.13, getting Py_None, Py_False,
Py_True, Py_Ellipsis and Py_NotImplemented singletons is now
implemented as function calls at the stable ABI level to hide
implementation details. Getting these constants still return borrowed
references.
Add _testlimitedcapi/object.c and test_capi/test_object.py to test
Py_GetConstant() and Py_GetConstantBorrowed() functions.
Mostly we unify the two different implementations of the conversion code (from PyObject * to int64_t. We also drop the PyArg_ParseTuple()-style converter function, as well as rename and move PyInterpreterID_LookUp().
This changes the free-threaded build to perform a stop-the-world pause
before deleting other thread states when forking and during shutdown.
This fixes some crashes when using multiprocessing and during shutdown
when running with `PYTHON_GIL=0`.
This also changes `PyOS_BeforeFork` to acquire the runtime lock
(i.e., `HEAD_LOCK(&_PyRuntime)`) before forking to ensure that data
protected by the runtime lock (and not just the GIL or stop-the-world)
is in a consistent state before forking.
These writes to `pending->calls_to_do` need to be atomic, because other threads
can read (atomically) from `calls_to_do` without holding `pending->mutex`.
* document equivalent command-line options for all environment variables
* document equivalent environment variables for all command-line options
* reduce the size of variable and option descriptions to minimum
* remove the ending period in single-sentence descriptions
Co-authored-by: Éric <merwok@netwok.org>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Keep Tools/build/deepfreeze.py around (we may repurpose it for deepfreezing non-code objects),
and keep basic "clean" targets that remove the output of former deep-freeze activities,
to keep the build directories of current devs clean.
Somehow we ended up with two separate counter variables tracking "the next function version".
Most likely this was a historical accident where an old branch was updated incorrectly.
This PR merges the two counters into a single one: `interp->func_state.next_version`.
There is a race between when `Thread._tstate_lock` is released[^1] in `Thread._wait_for_tstate_lock()`
and when `Thread._stop()` asserts[^2] that it is unlocked. Consider the following execution
involving threads A, B, and C:
1. A starts.
2. B joins A, blocking on its `_tstate_lock`.
3. C joins A, blocking on its `_tstate_lock`.
4. A finishes and releases its `_tstate_lock`.
5. B acquires A's `_tstate_lock` in `_wait_for_tstate_lock()`, releases it, but is swapped
out before calling `_stop()`.
6. C is scheduled, acquires A's `_tstate_lock` in `_wait_for_tstate_lock()` but is swapped
out before releasing it.
7. B is scheduled, calls `_stop()`, which asserts that A's `_tstate_lock` is not held.
However, C holds it, so the assertion fails.
The race can be reproduced[^3] by inserting sleeps at the appropriate points in
the threading code. To do so, run the `repro_join_race.py` from the linked repo.
There are two main parts to this PR:
1. `_tstate_lock` is replaced with an event that is attached to `PyThreadState`.
The event is set by the runtime prior to the thread being cleared (in the same
place that `_tstate_lock` was released). `Thread.join()` blocks waiting for the
event to be set.
2. `_PyInterpreterState_WaitForThreads()` provides the ability to wait for all
non-daemon threads to exit. To do so, an `is_daemon` predicate was added to
`PyThreadState`. This field is set each time a thread is created. `threading._shutdown()`
now calls into `_PyInterpreterState_WaitForThreads()` instead of waiting on
`_tstate_lock`s.
[^1]: 441affc9e7/Lib/threading.py (L1201)
[^2]: 441affc9e7/Lib/threading.py (L1115)
[^3]: 8194653279
---------
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Antoine Pitrou <antoine@python.org>
On Windows, time.monotonic() now uses the QueryPerformanceCounter()
clock to have a resolution better than 1 us, instead of the
gGetTickCount64() clock which has a resolution of 15.6 ms.
There are now at least two bytecodes that may attempt to optimize,
JUMP_BACK, and more recently, COLD_EXIT.
Only the JUMP_BACK was counting the attempt in the stats.
This moves that counter to uop_optimize itself so it should
always happen no matter where it is called from.
This isn't strictly necessary because the implementation of `gc_should_collect`
already checks `gcstate->enabled` in the free-threaded build, but it seems
like a good idea until the common pieces of gc.c and gc_free_threading.c are
refactored out.
This moves `current_fast_clear()` up so that the current thread state is
`NULL` while running `tstate_delete_common()`.
This doesn't fix any bugs, but it means that we are more consistent that
`_PyThreadState_GET() != NULL` means that the thread is "attached".
Return 0 on success. Set an exception and return -1 on error.
Fix os.timerfd_settime(): properly report exceptions on
_PyTime_FromSecondsDouble() failure.
No longer export _PyTime_FromSecondsDouble().
In free-threaded builds, running with `PYTHON_GIL=0` will now disable the
GIL. Follow-up issues track work to re-enable the GIL when loading an
incompatible extension, and to disable the GIL by default.
In order to support re-enabling the GIL at runtime, all GIL-related data
structures are initialized as usual, and disabling the GIL simply sets a flag
that causes `take_gil()` and `drop_gil()` to return early.
In general, when `_PyThreadState_GET()` is non-NULL then the current
thread is "attached", but there is a small window during
`PyThreadState_DeleteCurrent()` where that's not true:
tstate_delete_common() is called when the thread is detached, but before
current_fast_clear().
Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>
If a thread blocks while waiting on the `shared->mutex` lock, the array
of QSBR states may be reallocated. The `tstate->qsbr` values before the
lock is acquired may not be the same as the value after the lock is acquired.
Victor Stinner
Eric Snow
Sam Gross
Mark Shannon
Brett Simmers
Serhiy Storchaka
Brandt Bucher
Michael Droettboom
Bogdan Romanyuk
Guido van Rossum
Erlend E. Aasland
mpage
Donghee Na
Tian Gao
guangwu
Ken Jin
Pablo Galindo Salgado
Nikita Sobolev
Dino Viehland