I took a hack and made all C-based libvirt calls using tpool. It wasn't that bad..
https://github.com/maoy/nova/commit/757bfcb239c62c23c8455a507389efe9c1a2676e >From my limited testing, it works fine. At least snapshot doesn't block the compute node anymore. Yun On Tue, Mar 13, 2012 at 2:04 PM, Johannes Erdfelt <johan...@erdfelt.com> wrote: > On Tue, Mar 13, 2012, Yun Mao <yun...@gmail.com> wrote: >> There are two places in the current master branch that use tpool: >> NWFilterFirewall and XenAPISession. Are they safe? > > I've looked at XenAPISession and it appears to be safe. It doesn't use > logging nor any other locks. > > It does use other Python modules, but they appear to be fine too. > > I've never looked at NWFilterFirewall since I've been doing almost all > of my development on xenapi. > >> I think if it's a pure C-based API call, then monkey patch should not >> mess with it and it shouldn't try to reschedule among co-routines, >> right? > > If it's 100% C, then it's most likely safe. There are ways that it can > become unsafe, but it really needs to go out of it's way to do so. > >> After examining, the code, I see all libvirt-based calls are blocking, >> and XenAPIs are non-blocking. This probably makes a huge difference in >> a non-trivial deployment. However, libvirt-based KVM is probably the >> most widely adopted choice right now, which is very strange.. > > Yeah, it's not clear to me why only that one call in libvirt is handed > off to a tpool thread. I'm not all that familiar with libvirt, nor do I > use it, so I haven't looked into that. > > JE > > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
