 Home |
Products |
Support |
Community |
News |
xen-devel
Re: [Xen-devel] rcu support in xen
| To: | <ncmike@xxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] rcu support in xen |
| From: | Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> |
| Date: | Sun, 25 Mar 2007 09:28:30 +0100 |
| Delivery-date: | Sun, 25 Mar 2007 01:27:47 -0700 |
| Envelope-to: | www-data@xxxxxxxxxxxxxxxxxx |
| In-reply-to: | <20070324182214.GA9721@xxxxxxxxxxxxxxxxxxxxxx> |
| 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: | Acdut5FZz9DoRtqqEduGdgAX8io7RQ== |
| Thread-topic: | [Xen-devel] rcu support in xen |
| User-agent: | Microsoft-Entourage/11.2.5.060620 |
On 24/3/07 19:22, "Mike D. Day" <ncmike@xxxxxxxxxx> wrote:
> Due to recent conversion of get_domain_by_id to use rcu techniques I
> looked at the file xen/include/xen/rcupdate.h and noticed
> rcu_read_lock is defined as:
>
> define rcu_read_lock(x) do { } while (0)
>
> as well as the corresponding unlock and other related macros.
>
> Apologies if this has already been answered, but when will the real
> rcu code get into -unstable?
The whole point of RCU is that read-side critical sections have no (or very
little) synchronisation overhead. In Xen the rcu_read_[un]lock functions are
only present to make the code clearer and to seome extent self documenting.
On Linux they also disable involuntary preemption during the critical
section (which is not needed on Xen, of course).
So, in short, Xen already has a complete RCU implementation.
-- Keir
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | [Xen-devel] [Patch][RFC] correct retry limit of balloon, Akio Takebe |
|---|---|
| Next by Date: | Re: [Xen-devel] RFC: [0/2] Remove netloop by lazy copying in netback, Herbert Xu |
| Previous by Thread: | [Xen-devel] rcu support in xen, Mike D. Day |
| Next by Thread: | [Xen-devel] Re: rcu support in xen, Mike D. Day |
| Indexes: | [Date] [Thread] [Top] [All Lists] |
