| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
Re: [Xen-devel] [PATCH] Add RCU support into Xen - Repost
|
To: |
Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>, "Santos, Jose Renato G" <joserenato.santos@xxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx> |
|
Subject: |
Re: [Xen-devel] [PATCH] Add RCU support into Xen - Repost |
|
From: |
Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> |
|
Date: |
Tue, 30 Jan 2007 20:37:21 +0000 |
|
Cc: |
"Turner, Yoshio" <yoshio_turner@xxxxxx>, Jose Renato Santos <jsantos@xxxxxxxxxx>, G John Janakiraman <john@xxxxxxxxxxxxxxxxxxx> |
|
Delivery-date: |
Tue, 30 Jan 2007 12:37:11 -0800 |
|
Envelope-to: |
www-data@xxxxxxxxxxxxxxxxxx |
|
In-reply-to: |
<C1E559AE.81B2%Keir.Fraser@xxxxxxxxxxxx> |
|
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/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe> |
|
List-unsubscribe: |
<http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe> |
|
Sender: |
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
|
Thread-index: |
Acc5z5YIiS/CKex/Tb+azW+82olglwHqc/i/AMlxYuAAA1KFSgAAfs+1 |
|
Thread-topic: |
[Xen-devel] [PATCH] Add RCU support into Xen - Repost |
|
User-agent: |
Microsoft-Entourage/11.3.3.061214 |
On 30/1/07 8:23 pm, "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx> wrote:
> This would require some interaction with new find_domain_by_id(). The
> invocation of find_domain_by_id() and all subsequent uses of its return
> value will need to be contained within an rcu_read_lock()/rcu_read_unlock()
> pair which seems kind of a pain. Particularly since this documentation is
> weak -- it may not immediately be clear in future what is being protected by
> the rcu read-side region (since the lock routines do not take a parameter).
> And I'm not sure how the documentation helps: who will it be useful to?
Thinking about this a little more, we could wrap up the rcu_read_[un]lock
invocations into a more informative API in this case:
get_domain_by_id_rcu(d) and put_domain_rcu(d), analagous with
get_domain/put_domain. get_domain_by_rcu(d) would include an implicit
rcu_read_lock(), and put_domain_rcu(d) an implicit rcu_read_unlock().
I could certainly live with that, and then keep direct use of
rcu_read_lock()/rcu_read_unlock() for small critical regions (e.g., in the
implementation of get_domain_by_id()).
-- Keir
> Linux needs them for more than just documentation as it has to disable
> preemption (a feature which I don't expect Xen to ever acquire). I don't
> know whether it would have them otherwise.
>
> -- Keir
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home