From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: FW: Cancelling asynchronous operations in libxl
Date: Wed, 23 Oct 2013 13:23:29 -0400
Message-ID: <20131023172329.GE28413@phenom.dumpdata.com>
References: <4B8F5D33B081C044AA43634E84ED7F9616A83D@AMSPEX01CL03.citrite.net>
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To: Simon Beaumont <simon.beaumont@citrix.com>
Cc: "xs-devel@lists.xenserver.org" <xs-devel@lists.xenserver.org>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
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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?

Or is this mostly of 'the guest is doing something and does not seem
to have a vnc/console, lets kill it' ?

> 
> Cheers,
> 
> Si
> 
> [1]: https://github.com/xapi-project/xenopsd
> [2]: https://github.com/xapi-project/xenopsd/blob/master/xc/cancel_utils.ml#L101
> 
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