Re: orderlyShutdown question

On Fri, Jul 2, 2010 at 9:39 AM, Mark Miller <[email protected]> wrote:

> Hi Thomas, I see throughout the Runner code some support for registering
> and notifying deadManSwitches when a vat dies (becomes redirected to a
> DeadRunner). However, no one ever calls Runner.addDeadManSwitch(), so no
> deadManSwitches are ever getting registered. It looks like the intention is
> that HeadlessRunner keep all outgoing refs in its myDeadManSwitches
> collection, which, as the comment says, would then need to be a weak
> collection. Without doing so, not only do we get the problem you observed,
> we also fail to send __reactToLostClient messages on broken outgoing links.
>

Or rather, on severed outgoing links. The references in question are of
course not generally broken or there'd be no point.


>
> IIRC the redirector logic, making this change will also repair the problem
> you observe without further effort. But I'm not sure.
>
>
>
> On Fri, Jul 2, 2010 at 8:28 AM, Thomas Leonard <
> tal-v5nx5w6akNyLE8xUarVfuPLx9OUvmyODWmv/[email protected]> wrote:
>
>> On Fri, 2010-07-02 at 08:14 -0700, Kevin Reid wrote:
>> > On Jul 2, 2010, at 2:37, Thomas Leonard wrote:
>> >
>> > > I'm having a bit of trouble with shutting down vats. Here's some test
>> > > code:
>> > >
>> > > def makeVat := <unsafe:org.erights.e.elib.vat.makeVat>
>> > > def seedVat := <elang:interp.seedVatAuthor>(<unsafe>)
>> > >
>> > > def test() {
>> > >     def [_, vat] := seedVat("5")
>> > >     println(`created vat $vat`)
>> > >     println(`shutting down vat $vat`)
>> > >     def result := vat<-orderlyShutdown("reason")
>> > >
>> > >     return when (result) -> {
>> > >             println(`shutdown complete: $result`)
>> > >             test()
>> > >     }
>> > > }
>> > >
>> > > test()
>> > >
>> > > interp.blockAtTop()
>> > >
>> > >
>> > > The problem seems to be that once the vat is shut down, it doesn't
>> > > respond to __whenMoreResolved, so the caller is never notified.
>> >
>> > Is that a near or far reference to the vat object?
>> >
>> > It's OK to use vat objects from other threads, so try having a near
>> > reference instead. (And if that helps, then we can discuss the right
>> > way to have that reference at hand.)
>> >
>> > That said, it seems to me that having a reference into a dead vat (in
>> > general, whether the ref is to a vat object or just some other object
>> > in that vat) ought to resolve/WMR as a broken reference.
>>
>> It's near, but using "." instead of "<-" doesn't make any difference
>> (the result is still a promise). Here's a slightly simpler test-case:
>>
>> def makeVat := <unsafe:org.erights.e.elib.vat.makeVat>
>> def seedVat := <elang:interp.seedVatAuthor>(<unsafe>)
>>
>> def [_, vat] := seedVat("5")
>> println(`created vat $vat`)
>> println(`shutting down vat $vat`)
>> def result := vat.orderlyShutdown("reason")
>> println(`shutdown result: $result`)
>>
>> when (result) -> {
>>        println(`shutdown complete: $result`)
>> }
>>
>> interp.blockAtTop()
>>
>>
>> $ rune shutdown.e
>> created vat <Vat newSeedVat in <runs in newSeedVat>>
>> shutting down vat <Vat newSeedVat in <runs in newSeedVat>>
>> shutdown result: <Promise>
>> [hangs]
>>
>>
>>
>> --
>> Dr Thomas Leonard
>> IT Innovation Centre
>> 2 Venture Road
>> Southampton
>> Hampshire SO16 7NP
>>
>> Tel: +44 0 23 8076 0834
>> Fax: +44 0 23 8076 0833
>> mailto:tal-v5nx5w6akNyLE8xUarVfuPLx9OUvmyODWmv/[email protected]
>> http://www.it-innovation.soton.ac.uk
>>
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>
>
>
> --
> Text by me above is hereby placed in the public domain
>
>    Cheers,
>    --MarkM
>
>


-- 
Text by me above is hereby placed in the public domain

   Cheers,
   --MarkM

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