| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
Re: [Xen-devel] Re: [PATCH] EPT: Flush running cpus, add mask to flush
|
To: |
Jan Beulich <JBeulich@xxxxxxxxxx>, George Dunlap <George.Dunlap@xxxxxxxxxxxxx> |
|
Subject: |
Re: [Xen-devel] Re: [PATCH] EPT: Flush running cpus, add mask to flush when scheduled in |
|
From: |
Keir Fraser <keir.fraser@xxxxxxxxxxxxx> |
|
Date: |
Tue, 22 Sep 2009 09:07:17 +0100 |
|
Cc: |
Xiaohui Xin <Xiaohui.xin@xxxxxxxxx>, Xin Li <xin.b.li@xxxxxxxxx>, Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>, Paul Durrant <Paul.Durrant@xxxxxxxxxx>, Jun Nakajima <jun.nakajima@xxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx> |
|
Delivery-date: |
Tue, 22 Sep 2009 01:08:06 -0700 |
|
Envelope-to: |
www-data@xxxxxxxxxxxxxxxxxxx |
|
In-reply-to: |
<4AB893D60200007800016283@xxxxxxxxxxxxxxxxxx> |
|
List-help: |
<mailto:xen-devel-request@lists.xensource.com?subject=help> |
|
List-id: |
Xen developer discussion <xen-devel.lists.xensource.com> |
|
List-post: |
<mailto:xen-devel@lists.xensource.com> |
|
List-subscribe: |
<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe> |
|
List-unsubscribe: |
<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe> |
|
Sender: |
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
|
Thread-index: |
Aco7U2IefpmgYxlZTsKZqbAUubl6tgACFEwB |
|
Thread-topic: |
[Xen-devel] Re: [PATCH] EPT: Flush running cpus, add mask to flush when scheduled in |
|
User-agent: |
Microsoft-Entourage/12.20.0.090605 |
On 22/09/2009 08:07, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:
> Passing a pointer to the global cpu mask looks racy here: What if a CPU
> disappears from domain_dirty_cpumask under your feet?
I'm fixing this race before I apply the patch.
> Also, merely using cpus_complement() here seem inefficient: It should be
> possible to accumulate the flush activity, and avoid re-flushing on a CPU
> which e.g. got flushed on the second from the last run through this code
> (and not dirtied afterwards). I.e. I'd think there should be cpus_andnot()
> here, and setting of the bits as CPUs get dirtied.
I don't see how that is possible, as domain_dirty_cpumask can have changed
arbitrarily since the previous invocation of ept_sync_domain(), as can the
EPT tables. We have to assume every CPU has potentially stale cached
mappings.
-- Keir
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home