From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dario Faggioli <dario.faggioli@citrix.com>
Subject: Re: [PATCH v3 1/4] xen: add real time scheduler rtds
Date: Fri, 19 Sep 2014 11:45:04 +0200
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To: George Dunlap <george.dunlap@eu.citrix.com>
Cc: ian.campbell@citrix.com, xisisu@gmail.com, stefano.stabellini@eu.citrix.com, lu@cse.wustl.edu, ian.jackson@eu.citrix.com, xen-devel@lists.xen.org, ptxlinh@gmail.com, xumengpanda@gmail.com, Meng Xu <mengxu@cis.upenn.edu>, JBeulich@suse.com, chaowang@wustl.edu, lichong659@gmail.com, dgolomb@seas.upenn.edu
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On Thu, 2014-09-18 at 17:08 +0100, George Dunlap wrote:
> On 09/14/2014 10:37 PM, Meng Xu wrote:

> +static void
> +rt_dump_pcpu(const struct scheduler *ops, int cpu)
> +{
> +    struct rt_vcpu *svc =3D rt_vcpu(curr_on_cpu(cpu));
> +
> +    rt_dump_vcpu(ops, svc);
> +}
>=20
>=20
> These svc structures are allocated dynamically and may disappear at any=
=20
> time... I think you need the lock to cover this as well.
>=20
About locking, I agree with George that we need these functions to be
protected. Right now, this scheduler only uses one lock for everything,
so that would mean grabbing that lock here too.

This far from optimal, e.g., with scalability in mind (although, dumping
is going to be pretty rare an operation), but I think it'd be fine for
now.

In future (after 4.5), we may want to have a dedicated lock for all the
operations that manipulates the list of domains, as pretty much all our
other schedulers are doing.

Regards,
Dario

--=20
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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