Re: hang in gconfd
- From: Michael Meeks <michael ximian com>
- To: Havoc Pennington <hp redhat com>
- Cc: jacob berkman <jacob ximian com>, <gconf-list gnome org>, gnome-2-0 <gnome-2-0-list gnome org>, <orbit-list gnome org>
- Subject: Re: hang in gconfd
- Date: Mon, 10 Dec 2001 08:25:55 -0500 (EST)
Hi Havoc,
On 9 Dec 2001, Havoc Pennington wrote:
> FWIW this has been happening (rarely) for a long time, even in gconf 1
> with ORBit 1. It is unreproduceable as far as I can tell. I asked for
> assistance with it on orbit-list once before, I think, as I have no
> idea what would cause an ORBit outgoing oneway call to stick like
> this.
Well - it seems easily possible to me that the buffer in the
transfer process is full, and the other end is not processing the data.
Clearly - unless you want to delay the oneway call invocation -
which as you suggest will cause:
oneway_method (foo, ev);
exit (0);
Not to work [ not that this is an issue, since clearly shutdown
methods are the way to make this work ].
Then you have to block at some stage; it is not possible to write
an inifinite amount of 'ping' data to a remote component that is not
responding (for whatever reason).
> If oneway calls can hang, then we have a big problem, because I have
> no idea how to make a server robust if any client can hang it.
Well - oneway _helps_ avoid the server hanging; but - if, as I
suggested previously, instead of using 'ping' - you use the connection
status; available via:
CORBA_Object_non_existant.
you win every way; since it involves you in no CORBA method calls
to remote servers, no contexts switches to handle that data, no redundant
data going into buffers, etc. etc. etc.
Of course - if you don't want to have a timeout sitting there
polling things, you can use ORBit_small_[un]listen_for_broken, which will
give you a notification as soon as the remote end dies - saving ugly
timeouts and less efficient polling.
> Or if they only hang in avoidable circumstances, I'd like to know
> what those are.
Well - when the buffer is full; as I said, writes are blocking; it
would be possible to work around this in ORBit2 with relative ease in
fact; simply marking buffers as blocking, queueing all further data on
that connection and waiting till we get an event on the socket to write
more data;
> My understanding is that is not supposed to block.
It's not possible to make it fully non blocking without the above
ORB changes. I've put them on my TODO - but my TODO is growing in an
unbounded sort of way ... I'm happy to help point you / someone at the
bits to hack though ... it would be wonderful to have this feature.
Regards,
Michael.
--
mmeeks gnu org <><, Pseudo Engineer, itinerant idiot
[
Date Prev][
Date Next] [
Thread Prev][
Thread Next]
[
Thread Index]
[
Date Index]
[
Author Index]