On Fri, Jul 29, 2016 at 03:35:06PM +0100, Ian Jackson wrote: > Wei Liu writes ("Re: [XTF PATCH] xtf-runner: fix two synchronisation issues"): > > On Fri, Jul 29, 2016 at 03:21:52PM +0100, Ian Jackson wrote: > > > Wei Liu writes ("[XTF PATCH] xtf-runner: fix two synchronisation issues"): > > > > There were two synchronisation issues for the old code: > > > > > > > > 1. There was no guarantee that guest console was ready before "xl > > > > console" invocation. > > > > > > Is this not a bug in xl console ? > > > > I don't think so. It gives up when it can't get tty from xenstore. I > > think that's reasonable. > > If you say > xl create /etc/xen/foo.cfg > xl console foo > then surely you shouldn't find that xl console fails because of some > race. >
What if the guest just doesn't have / want a console? In that case there will never be a tty node in xenstore, so xl console should wait forever for one? What is the expectation for this case? > > > > 2. Poll xenstore guest console node to make sure console is available > > > > before "xl console" invocation. > > > > > > Users of things like xl shouldn't need to prat about in xenstore too. > > > > What does this mean? > > I mean that xenstore is part of the implementation of libxl, not part > of its public interface. In this sense it is a bit like libxc. > libxl callers should (in general) not look at xenstore - and of > course they should therefore;2~ not need to do so. > In this particular case, all nodes that xtf-runner code reles on are documented, so I already consider them public interfaces. > If the xtf runner needs to look in xenstore (other than perhaps if > it's doing strange things there as part of its test cases) then that > means there is some interface or capability missing in libxl. > I don't disagree. But the missing capability won't be backported to older version of Xen. I don't want to eliminate the possibility for running xtf on older versions of Xen. > OTOH I'm slightly confused because I was under the impression that > there was a polling loop in xl console (xenconsole) already. > > Maybe I don't understand your problem. > The issue is that when it tries to get tty from xenstore and there isn't one, it gives up. Your polling loop is something else. http://osstest.xs.citrite.net/~osstest/testlogs/logs/66855/test-xtf-amd64-amd64-1/10.ts-xtf-fep.log Wei. > Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel