[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] FW: Cancelling asynchronous operations in libxl
On Wed, 2013-10-23 at 13:23 -0400, Konrad Rzeszutek Wilk wrote: > On Tue, Oct 15, 2013 at 04:08:31PM +0000, Simon Beaumont wrote: > > We're in the process of porting xenopsd[1] to libxl, rather than > driving libxc manually. > > > > Using our libxc-based backend, we are able to cancel operations. For > operations that are using XenStore watches we wrap these in a > cancellable_watch[2], and for operations that make use of a subprocess > we send SIGKILL when we wish to cancel the associated task. We would > then instrument any necessary cleanup by hand on a best-effort basis. > > > > With the move to libxl, a lot of this control will be abstracted > away and it is unclear how best to allow long-running tasks to be > cancelled. It seems most of these operations could be executed > asynchronously but we wonder if it is possible to cancel them, or how > we could add cancellation functionality to these operations? > > Are there specific operations that you are focusing on to cancel? Yes, this would be good to know. Ian J would know better than I but AIUI there is currently no generic support for cancelling an asynchronous op in libxl. I'm sure we could find a way to add this, for example as an abort after the current "step" succeeds/times out/fails. > Or is this mostly of 'the guest is doing something and does not seem > to have a vnc/console, lets kill it' ? For killing libxl_domain_destroy should be fine to call even if there is an async op pending on that domain, the async op will naturally fail, it'll probably log a lot but should do so gracefully. If there are cases which do not we should fix them, since they would represent a bug irrespective of any killing of the domain from under the op's feet. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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