From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
David Vrabel <david.vrabel@citrix.com>,
xen-devel@lists.xen.org
Subject: Re: [PATCH 1/3] x86/xen: allow for privcmd hypercalls to be preempted
Date: Wed, 12 Feb 2014 10:10:44 +0000 [thread overview]
Message-ID: <52FB48A4.9090205@citrix.com> (raw)
In-Reply-To: <1392197930.13563.7.camel@kazak.uk.xensource.com>
On 12/02/14 09:38, Ian Campbell wrote:
> On Tue, 2014-02-11 at 19:19 +0000, David Vrabel wrote:
>> Implement is_premptible_hypercall() by adding a second hypercall page
>> (preemptible_hypercall_page, copied from hypercall_page). Calls made
>> via the new page may be preempted.
> Wouldn't a per-cpu flag variable set for the duration of privcmd_call do
> the job just as well without requiring per-arch knowledge?
>
> Ian.
>
Why should privcmd_call be the only preemptible calls? This code allows
anyone to voluntarily use the preemptible_hypercall_page. I would not
be surprised if modules like gntdev could do with some preemption, but
it is the long-running toolstack hypercalls which are currently killing
any loaded XenServer system.
~Andrew
next prev parent reply other threads:[~2014-02-12 10:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-11 19:19 [PATCHv1 0/3]: xen: voluntary preemption for privcmd hypercalls David Vrabel
2014-02-11 19:19 ` [PATCH 1/3] x86/xen: allow for privcmd hypercalls to be preempted David Vrabel
2014-02-12 9:38 ` Ian Campbell
2014-02-12 10:10 ` Andrew Cooper [this message]
2014-02-12 10:18 ` Ian Campbell
2014-02-11 19:19 ` [PATCH 2/3] arm/xen: add stub is_preemptible_hypercall() David Vrabel
2014-02-11 19:19 ` [PATCH 3/3] xen/events: schedule if the interrupted task is in a preemptible hypercall David Vrabel
2014-02-12 11:59 ` Jan Beulich
2014-02-12 12:54 ` David Vrabel
2014-02-12 13:56 ` Jan Beulich
2014-02-12 16:35 ` David Vrabel
2014-02-12 16:47 ` Jan Beulich
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