From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH 17/29] libxl: cancellation: Provide public ao cancellation API Date: Tue, 24 Mar 2015 11:48:57 +0000 Message-ID: <1427197737.21742.361.camel@citrix.com> References: <1423599016-32639-1-git-send-email-ian.jackson@eu.citrix.com> <1423599016-32639-18-git-send-email-ian.jackson@eu.citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1423599016-32639-18-git-send-email-ian.jackson@eu.citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Jackson Cc: xen-devel@lists.xensource.com, Euan Harris List-Id: xen-devel@lists.xenproject.org On Tue, 2015-02-10 at 20:10 +0000, Ian Jackson wrote: > + /* > + * For nested aos: > + * Semantically, cancellation affects the whole tree of aos, > + * not just the parent. > + * libxl__ao_cancellable.ao refers to the child, so > + * that the child callback sees the right ao. (After all, > + * it was code dealing with the child that set .ao.) > + * But, the cancellable is recorded on the "cancellables" list > + * for the ultimate root ao, so that every possible child > + * cancellation occurs as a result of the cancellation of the > + * parent. > + * We set ao->cancelling only in the root. > + */ WRT this, given a tree of ao's, which ones need to be cancellable for a cancellation to succeed? I would assume all of them do, or else the cancellation can only occur if/when the non-cancellable ones happen to end? Do we(/are we going to) take steps to stop new non-cancellable ao's to the tree once the root is cancelled? Ian.