[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] xl shutdown --wait "racy"
Thursday, April 17, 2014, 8:09:39 PM, you wrote: > George Dunlap writes ("Re: [Xen-devel] xl shutdown --wait "racy""): >> On Wed, Apr 16, 2014 at 3:13 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> >> wrote: >> > It is waiting for the domain to be shutdown (state 's') not for the >> > domain to be destroyed. So it's doing what it said it would (I >> > appreciate you might not find this distinction helpful under the >> > circumstances...) >> >> For any reasonable person's definition of "shutdown", it does *not* >> wait until it's shutdown. "In the shutdown state" is not something >> anyone outside of Xen cares about: what they care about is being able >> to, for example, start the domain again (or start a domain that >> depends on resources currently held by the shutting down domain). > Quite. I think this is simply a bug and it should wait for the domain > to be destroyed. It seems the shutdown is racy in another aspect as well, the code in "wait_for_domain_deaths" on receiving a event doesn't actually check if it's a event related to the domain it should wait for. It only checks a count (1 if you shutdown only one domain, nb_domains -1 if you shutdown all). To be less error prone it should ideally pass an array of domids it needs to wait for through to wait_for_domain_deaths and check on it. > It's IMO a tolerable side-effect if this means that when the domain > shuts down in a way that causes it to be preserved (ie the daemonic xl > doesn't reap it) xl shutdown -w gets stuck. (There should be an > option to restore the former behaviour but it should not be the > default.) > Ideally xl would record something somewhere so that it would know > what's going on and could make "xl shutdown -w" fail in the default > case if it's going to wait "forever". There isn't a generic timeout function that could raise an timeout event when it is taking too long ? But i'm running into my all too limited C skills here .. (passive reading is fairly ok, actively building something somewhat more complex in a sane way is not :-) ) > Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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