From: Ian Jackson <ian.jackson@citrix.com>
To: "Durrant, Paul" <pdurrant@amazon.co.uk>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Julien Grall <julien@xen.org>, Wei Liu <wl@xen.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Andrew Cooper <Andrew.Cooper3@citrix.com>,
"jandryuk@gmail.com" <jandryuk@gmail.com>,
George Dunlap <George.Dunlap@citrix.com>,
Jan Beulich <jbeulich@suse.com>,
Anthony Perard <anthony.perard@citrix.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [Xen-devel] [PATCH v3 4/6] libxl: allow creation of domains with a specified or random domid
Date: Fri, 17 Jan 2020 11:35:39 +0000 [thread overview]
Message-ID: <24097.39947.159860.741920@mariner.uk.xensource.com> (raw)
In-Reply-To: <402866798e2a40e192fd8052548374c5@EX13D32EUC003.ant.amazon.com>
Durrant, Paul writes ("RE: [PATCH v3 4/6] libxl: allow creation of domains with a specified or random domid"):
> [Ian:]
> > I think there are only two possible solutions:
> >
> > - Check the domain's entry in the recent list *after* creating
> > the domain in Xen. This involves accepting that we will
> > reuse the domid but only for a domain we are in the early
> > stages of constructing, so hopefully without bad consequence?
> >
> > - Take the recent domid lock.
> >
>
> Or take a global file lock in libxl around domain creation and destruction?
We want domain construction to be concurrent, when it can be. So I
think a lock around just xc_domain_create is OK but a lock around the
whole operation is not.
> > Also, it seems to me that we should check the recent domid list if we
> > let Xen choose the domid. Maybe that can be in a subsequent patch...
>
> Well, we could solve all this, remove the need for a file and all the associated complexity by simply keeping history inside the hypervisor. I don't know how the Xen maintainers will feel about that though, as Xen itself shouldn't have a problem with eager domid re-use.
I think this doesn't need to be done in the hypervisor so I am
inclined to say it shouldn't be. Also, there is a lot of policy here...
Ian.
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next prev parent reply other threads:[~2020-01-17 11:36 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 9:35 [Xen-devel] [PATCH v3 0/6] xl/libxl: domid allocation/preservation changes Paul Durrant
2020-01-16 9:35 ` [Xen-devel] [PATCH v3 1/6] libxl: add definition of INVALID_DOMID to the API Paul Durrant
2020-01-16 9:35 ` [Xen-devel] [PATCH v3 2/6] libxl_create: make 'soft reset' explicit Paul Durrant
2020-01-16 9:35 ` [Xen-devel] [PATCH v3 3/6] libxl: add infrastructure to track and query 'retired' domids Paul Durrant
2020-01-16 18:27 ` Ian Jackson
2020-01-17 9:26 ` Durrant, Paul
2020-01-17 11:31 ` Ian Jackson
2020-01-16 9:36 ` [Xen-devel] [PATCH v3 4/6] libxl: allow creation of domains with a specified or random domid Paul Durrant
2020-01-16 9:40 ` Jan Beulich
2020-01-16 9:46 ` Durrant, Paul
2020-01-16 9:59 ` Jan Beulich
2020-01-16 15:53 ` Jason Andryuk
2020-01-16 18:36 ` Ian Jackson
2020-01-17 9:37 ` Durrant, Paul
2020-01-17 11:35 ` Ian Jackson [this message]
2020-01-17 12:06 ` Durrant, Paul
2020-01-17 15:30 ` Ian Jackson
2020-01-20 8:18 ` Durrant, Paul
2020-01-16 9:36 ` [Xen-devel] [PATCH v3 5/6] xl.conf: introduce 'domid_policy' Paul Durrant
2020-01-16 18:37 ` Ian Jackson
2020-01-16 9:36 ` [Xen-devel] [PATCH v3 6/6] xl: allow domid to be preserved on save/restore or migrate Paul Durrant
2020-01-16 18:39 ` Ian Jackson
2020-01-16 18:43 ` [Xen-devel] [PATCH v3 0/6] xl/libxl: domid allocation/preservation changes Ian Jackson
2020-01-17 9:11 ` Durrant, Paul
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