Re: [non-stop] 07/10 non-stop inferior control

Pedro Alves
2008-06-25T20:03:49Z

A Wednesday 25 June 2008 20:44:09, Daniel Jacobowitz wrote:
> On Sun, Jun 15, 2008 at 10:05:16PM +0100, Pedro Alves wrote:
> > It is also needed to have support to interrupt/suspend a simple
> > thread so a new target_stop_ptid method was added to request
> > the target to interrupt a single thread.
>
> How about adding a ptid argument to to_stop instead? I think the code
> will be shared in most cases.
>

Sure, I'll do that. It was a way to not have to update all
targets before review. :-)

> > @@ -1810,11 +1847,16 @@ handle_inferior_event (struct execution_
> > && ecs->ws.kind != TARGET_WAITKIND_SIGNALLED &&
> > ecs->new_thread_event) add_thread (ecs->ptid);
> >
> > - /* Mark all threads as not-executing. In non-stop, this should be
> > - adjusted to only mark ecs->ptid. */
> > - if (ecs->ws.kind != TARGET_WAITKIND_IGNORE
> > - && stop_soon != STOP_QUIETLY)
> > - set_executing (pid_to_ptid (-1), 0);
> > + if (ecs->ws.kind != TARGET_WAITKIND_IGNORE)
> > + {
> > + /* Mark the stopped threads accordingly. */
> > + if (!non_stop
> > + || ecs->ws.kind == TARGET_WAITKIND_EXITED
> > + || ecs->ws.kind == TARGET_WAITKIND_SIGNALLED)
> > + set_executing (pid_to_ptid (-1), 0);
> > + else
> > + set_executing (ecs->ptid, 0);
> > + }
> >
> > switch (ecs->ws.kind)
> > {
>
> Are we going to miss the stop_soon check here?

Indeed, I'll recheck carefully. It used to be needed, and the
symptom was a nice internal_error. It isn't happening, which
probably means I either fixed the real issue, or I missed
something. :-)

>
> > - switch_to_thread (tp->ptid);
> > + if (non_stop)
> > + context_switch_to (tp->ptid);
> > + else
> > + switch_to_thread (tp->ptid);
> > +
>
> Ow ow my head, I really wish we didn't need both of these. We'll
> never keep track of which is which.

Easy, It's always both, except when it's a temporary switch to another
thread and back. :-)

> Will we eventually be able to merge them?

Oh, yeah. context_switch(_to) is a dying species. I'm working on getting
rid of it. Then we'll only have switch_to_thread (which should go to,
if/when we switch to have a frame cache per thread). stop_pc (the other
job of switch_to_thread) isn't doing its job in some cases either,
and we could remove it. Say:

<stop at thread 1> (sets stop_pc)
p $pc = xxx
thread 2 (sets stop_pc)
thread 1 (sets stop_pc, but it's no longer the original...)

We can switch to always using read_pc() (or equivalent).

I have all-stop mode / linux mostly covered, now I'm making sure remote
always has a thread, monitor targets will be easy, and win32-nat.c
is also taken care of. Will need to convert non-stop too, but
that'll take a bit. I prefer that this series goes in first,
otherwise, we'll never get this done. Baby steps, please. :-)

>
> > - add_prefix_cmd ("thread", class_run, thread_command, _("\
> > + c = add_prefix_cmd ("thread", class_run, thread_command, _("\
> > Use this command to switch between threads.\n\
> > The new thread ID must be currently known."),
> > &thread_cmd_list, "thread ", 1, &cmdlist);
>
> Indentation on that last line.
>
> Otherwise OK.

Thanks a bunch. I'll get back once I resolve the issues
you mentioned.

--
Pedro Alves