(no subject)

[Neil Jerram]

address@hidden (Ludovic Courtès) writes:

> I should have mentioned this one:
> http://thread.gmane.org/gmane.comp.programming.garbage-collection.boehmgc/3185
>  .
>
> This is normally somewhat fixed in current BDW-GC CVS, but Guile itself
> may have troubles of its own dealing with cancellation.

Thanks.  I thought already about cancellation, but I couldn't see
anything in the test program that would do that.  Do you know of
anything in that program, or in BDW-GC, that does a pthread_cancel?

> The critical section issue should be orthogonal, though.

Yes.

> Here it is:

Thanks, and thanks to Ken also.

I've cherry-picked the following branch_release-1-8 fixes.

commit 499c43b03225abb8d3af9087b7630d523b74e13a
Author: Neil Jerram <address@hidden>
Date:   Thu Mar 5 20:03:33 2009 +0000

    Avoid throw from critical section, given invalid sigaction call

(This is for a different critical section problem, but which still
occurs (prior to this commit) in master.)

commit 3009b5d557e1ebfd828fd0de9b1da5abb2f6ec9a
Author: Neil Jerram <address@hidden>
Date:   Tue Mar 10 23:55:31 2009 +0000

    Fix spurious `throw from within critical section' errors

(This is the commit that I hope will fix the errors that you're seeing.)

Can you see how the test runs now?

Also, can I check my thinking on one other fix, and how it
interacts with BDW-GC?

commit 2bfcaf2605f8366d8c708c148bde5313b88497e0
Author: Neil Jerram <address@hidden>
Date:   Wed Mar 4 23:45:11 2009 +0000

    Lock ordering: don't allocate when in critical section 
(scm_sigaction_for_thread)

With BDW-GC I believe that allocation in a critical section is no longer
a problem, specifically because

- the stop-the-world mechanism uses signals and sigsuspend - whereas
  Guile GC used mutexes - and hence there are no concerns about lock
  ordering

- it doesn't matter if there are threads waiting for the critical
  section when a GC happens, because the signal mechanism will still
  interrupt them.

Is that right?

Thanks!
        Neil