Commit Graph

21 Commits

Author SHA1 Message Date
Damien George
d54208a2ff py/scheduler: Implement VM abort flag and mp_sched_vm_abort().
This is intended to be used by the very outer caller of the VM/runtime.  It
allows setting a top-level NLR handler that can be jumped to directly, in
order to forcefully abort the VM/runtime.

Enable using:

    #define MICROPY_ENABLE_VM_ABORT (1)

Set up the handler at the top level using:

    nlr_buf_t nlr;
    nlr.ret_val = NULL;
    if (nlr_push(&nlr) == 0) {
        nlr_set_abort(&nlr);
        // call into the VM/runtime
        ...
        nlr_pop();
    } else {
        if (nlr.ret_val == NULL) {
            // handle abort
            ...
        } else {
            // handle other exception that propagated to the top level
            ...
        }
    }
    nlr_set_abort(NULL);

Schedule an abort, eg from an interrupt handler, using:

    mp_sched_vm_abort();

Signed-off-by: Damien George <damien@micropython.org>
2023-03-21 18:08:57 +11:00
David Lechner
a1ef5ac65d py/scheduler: Use MP_REGISTER_ROOT_POINTER().
This uses MP_REGISTER_ROOT_POINTER() to register sched_queue
instead of using a conditional inside of mp_state_vm_t.

Signed-off-by: David Lechner <david@pybricks.com>
2022-07-18 13:52:01 +10:00
Jim Mussared
8db99f11a7 py/scheduler: De-inline and fix race with pending exception / scheduler.
The optimisation that allows a single check in the VM for either a pending
exception or non-empty scheduler queue doesn't work when threading is
enabled, as one thread can clear the sched_state if it has no pending
exception, meaning the thread with the pending exception will never see it.

This removes that optimisation for threaded builds.

Also fixes a race in non-scheduler builds where get-and-clear of the
pending exception is not protected by the atomic section.

Also removes the bulk of the inlining of pending exceptions and scheduler
handling from the VM. This just costs code size and complexity at no
performance benefit.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
2022-07-12 15:54:33 +10:00
Damien George
75506e496f py/scheduler: Add support for scheduling static C-based callbacks.
If MICROPY_SCHEDULER_STATIC_NODES is enabled then C code can declare a
static mp_sched_node_t and schedule a callback using
mp_sched_schedule_node().  In contrast to using mp_sched_schedule(), the
node version will have at most one pending callback outstanding, and will
always be able to schedule if there is nothing already scheduled on this
node.  This guarantees that the the callback will be called exactly once
after it is scheduled.

Signed-off-by: Damien George <damien@micropython.org>
2022-04-14 12:31:53 +10:00
David Lechner
259d9b69fe py/mpstate: Schedule KeyboardInterrupt on main thread.
This introduces a new macro to get the main thread and uses it to ensure
that asynchronous exceptions such as KeyboardInterrupt (CTRL+C) are only
scheduled on the main thread. This is more deterministic than being
scheduled on a random thread and is more in line with CPython that only
allow signal handlers to run on the main thread.

Fixes issue #7026.

Signed-off-by: David Lechner <david@pybricks.com>
2021-06-19 09:49:00 +10:00
David Lechner
ca920f7218 py/mpstate: Make exceptions thread-local.
This moves mp_pending_exception from mp_state_vm_t to mp_state_thread_t.
This allows exceptions to be scheduled on a specific thread.

Signed-off-by: David Lechner <david@pybricks.com>
2021-06-19 09:43:44 +10:00
Damien George
aa061ae391 py/scheduler: Add missing MICROPY_WRAP_MP_SCHED_EXCEPTION usage.
This was missed in commit 7cbf826a95.

Signed-off-by: Damien George <damien@micropython.org>
2021-05-01 23:10:26 +10:00
Damien George
916c3fd23f py/scheduler: Add optional port hook for when something is scheduled.
So that a port can "wake up" when there is work to do.

Signed-off-by: Damien George <damien@micropython.org>
2021-04-30 15:32:16 +10:00
Damien George
e9e9c76ddf all: Rename mp_keyboard_interrupt to mp_sched_keyboard_interrupt.
To match mp_sched_exception() and mp_sched_schedule().

Signed-off-by: Damien George <damien@micropython.org>
2021-04-30 15:13:43 +10:00
Damien George
7cbf826a95 py/scheduler: Add mp_sched_exception() to schedule a pending exception.
This helper is added to properly set a pending exception, to mirror
mp_sched_schedule(), which schedules a function.

Signed-off-by: Damien George <damien@micropython.org>
2021-04-30 15:13:43 +10:00
Damien George
f792e6c283 py/scheduler: Convert mp_sched_full and mp_sched_num_pending to macros.
So they are guaranteed to be inlined within functions like
mp_sched_schedule which may be located in a special memory region.
2020-05-08 23:20:45 +10:00
Damien George
544c308c18 py/scheduler: Add option to wrap mp_sched_schedule in arbitrary attr.
So ports can put it in a special memory section if needed.
2020-04-30 23:47:11 +10:00
Jim Mussared
8470cd0be9 py/scheduler: Add assert that scheduler is locked when unlocking.
And add a test that shows how this can happen when multiple threads are
accessing the scheduler, which fails if atomic sections are not used.
2020-04-13 21:55:47 +10:00
Jim Mussared
243805d776 py/scheduler: Fix race in checking scheduler pending state.
Because the atomic section starts after checking whether the scheduler
state is pending, it's possible it can become a different state by the time
the atomic section starts.

This is especially likely on ports where MICROPY_BEGIN_ATOMIC_SECTION is
implemented with a mutex (i.e. it might block), but the race exists
regardless, i.e. if a context switch occurs between those two lines.
2020-04-13 21:55:47 +10:00
Damien George
abe2caf6df py/scheduler: Move clearing of kbd traceback to mp_keyboard_interrupt.
This is a more logical place to clear the KeyboardInterrupt traceback,
right before it is set as a pending exception.  The clearing is also
optimised from a function call to a simple store of NULL.
2020-02-07 16:08:31 +11:00
Damien George
8fb5c8fdd5 py/scheduler: Allow a port to specify attrs for mp_keyboard_interrupt.
Functions like mp_keyboard_interrupt() may need to be called from an IRQ
handler and may need to be in a special memory section, so provide a
generic wrapping macro for a port to do this.  The macro name is chosen to
be MICROPY_WRAP_<function name in uppercase> so that (in the future with
more wrappers) each function could potentially be handled separately.
2020-02-07 16:08:29 +11:00
Damien George
9efb36bfa6 py/scheduler: Move mp_keyboard_interrupt from lib/utils to py core.
This function is tightly coupled to the state and behaviour of the
scheduler, and is a core part of the runtime: to schedule a pending
exception.  So move it there.
2020-02-07 16:08:26 +11:00
Damien George
98a3911c43 py/scheduler: Add "raise_exc" argument to mp_handle_pending.
Previous behaviour is when this argument is set to "true", in which case
the function will raise any pending exception.  Setting it to "false" will
cancel any pending exception.
2020-02-07 16:08:20 +11:00
Jim Mussared
bc66fe9064 py/scheduler: Rename sched_stack to sched_queue.
Behaviour was changed from stack to queue in
8977c7eb58, and this updates variable names
to match.  Also updates other references (docs, error messages).
2019-07-17 16:09:32 +10:00
Andrew Leech
8977c7eb58 py/scheduler: Convert micropythyon.schedule() to a circular buffer.
This means the schedule operates on a first-in, first-executed manner
rather than the current last-in, first executed.
2019-03-26 16:35:42 +11:00
Damien George
6e74d24f30 py: Add micropython.schedule() function and associated runtime code. 2017-03-20 15:20:26 +11:00