 Home |
Products |
Support |
Community |
News |
xen-devel
Re: spinlock requests (was RE: [Xen-devel] [Patch] don't spin with irq d
| To: | Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxxxx>, Juergen Gross <juergen.gross@xxxxxxxxxxxxxxxxxxx> |
|---|---|
| Subject: | Re: spinlock requests (was RE: [Xen-devel] [Patch] don't spin with irq disabled) |
| From: | Keir Fraser <keir.fraser@xxxxxxxxxxxxx> |
| Date: | Fri, 27 Mar 2009 18:12:05 +0000 |
| Cc: | "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx> |
| Delivery-date: | Fri, 27 Mar 2009 11:12:36 -0700 |
| Envelope-to: | www-data@xxxxxxxxxxxxxxxxxxx |
| In-reply-to: | <f239717e-fc9a-4825-b2ee-ed9a30e80836@default> |
| 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: | AcmvBiPHpzj7gY1ESOy0A/hQWWGacwAAWTu1 |
| Thread-topic: | spinlock requests (was RE: [Xen-devel] [Patch] don't spin with irq disabled) |
| User-agent: | Microsoft-Entourage/12.15.0.081119 |
On 27/03/2009 18:00, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote: >> What try_readlock would that be? There is no such function. > > Oops, my memory was faulty. It is read_lock() itself > that decrements the lock and then re-increments it. > This appeared to be causing the race. When I added > debug code, the problem went away (which was what led > me to the "hack" working version). Well the race is still impossible afaics. Unless your _raw_rw_is_write_locked() was checking for ==0 rather than <=0. I think something fishy was going on in your actual original implementation if is_write_locked(). :-) -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel |
| Previous by Date: | Re: [Xen-users] Cluster (VPC), Eucalyptus and preferred distribution to it., Nathan Stratton |
|---|---|
| Next by Date: | Re: [Xen-devel] atomic counters larger than 24 bits?, Jeremy Fitzhardinge |
| Previous by Thread: | RE: spinlock requests (was RE: [Xen-devel] [Patch] don't spin with irq disabled), Dan Magenheimer |
| Next by Thread: | Re: spinlock requests (was RE: [Xen-devel] [Patch] don't spin with irq disabled), Juergen Gross |
| Indexes: | [Date] [Thread] [Top] [All Lists] |
