WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] [PATCH 2/3] blktap: mb fixes

To: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 2/3] blktap: mb fixes
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Tue, 07 Nov 2006 12:31:30 +0000
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 07 Nov 2006 04:32:23 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20061107121944.GG2868%yamahata@xxxxxxxxxxxxx>
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: AccCaKaz5QlwxG5bEdurgAAX8io7RQ==
Thread-topic: [Xen-devel] [PATCH 2/3] blktap: mb fixes
User-agent: Microsoft-Entourage/11.2.5.060620
On 7/11/06 12:19, "Isaku Yamahata" <yamahata@xxxxxxxxxxxxx> wrote:

> Hmm.. since you don't believe any race, then please revert
> this mb patch except NULL check chunk.
> I certainly observed that tapdisk failed to get new request on IA64.
> If it is really caused by the race, I will sent a patch again.
> (or I'll sent another patch which fixes another issues)

I agreed the other barriers were needed, just not that one. If it were
required, we'd have the same race in blkback.c.

> BTW,
> why is wmb() in write_rsp_to_ring() of tools/blktap/drivers/tapdisk.c
> necessary?
> RING_PUSH_RESPONSES() of kick_responses() issues wmb() so that
> wmb() in write_rsp_to_ring() isn't needed, I think.

I agree. I'll remove it.

 -- Keir



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>