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

[Xen-devel] Re: [PATCH 06/20] x86/ticketlock: make __ticket_spin_trylock

To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: [Xen-devel] Re: [PATCH 06/20] x86/ticketlock: make __ticket_spin_trylock common
From: Américo Wang <xiyou.wangcong@xxxxxxxxx>
Date: Sat, 13 Nov 2010 18:17:32 +0800
Cc: Nick Piggin <npiggin@xxxxxxx>, Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Peter Zijlstra <peterz@xxxxxxxxxxxxx>, Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx>, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>, Jan Beulich <JBeulich@xxxxxxxxxx>, Linux Virtualization <virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx>, Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>, Avi Kivity <avi@xxxxxxxxxx>, "H. Peter Anvin" <hpa@xxxxxxxxx>
Delivery-date: Mon, 15 Nov 2010 01:22:47 -0800
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:date:from:to:cc:subject :message-id:references:mime-version:content-type:content-disposition :in-reply-to:user-agent; bh=Z8OiFjVu8j1ru7U04taAxiNwvxMJ6Epg94wpyVUot+Y=; b=R/SC0h2A2J/0VcTdzEoDltu9FYMD4K+xivO9Wle5cf+T9L4oLTcz8aWd0fNiRY19cf XmYuNS95byJmKDOjooPTRbQ6QRFDxXLTvQAH4wWgiiG13+xjjxR1GEKhkpLrpv/moUp6 znd96jnSrvWepfzU484sxzdxOKIVKlpwG1WhM=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=xAQjf6LmAPEUeBIWLO58TkLIR8TtEEJHaC2e0yW+gMywGLIXY0qnAX6U2Y4PabFKi6 2PXoj+5mOocgxFjXCCLTWCw0EjW9R6P6R1OPmwBa78g3rNckko3EKmmgD6q8jgxEuaDM HS4V2bXAJTy86vjptSS8UEVZvkImLse2mSND4=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4cea7b0804de5a2c1249034fc5c4840ade043ff4.1288794124.git.jeremy.fitzhardinge@xxxxxxxxxx>
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>
References: <cover.1288794124.git.jeremy.fitzhardinge@xxxxxxxxxx> <4cea7b0804de5a2c1249034fc5c4840ade043ff4.1288794124.git.jeremy.fitzhardinge@xxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.19 (2009-01-05)
On Wed, Nov 03, 2010 at 10:59:47AM -0400, Jeremy Fitzhardinge wrote:

>+      union {
>+              struct __raw_tickets tickets;
>+              __ticketpair_t slock;
>+      } tmp, new;
>+      int ret;
>+
>+      tmp.tickets = ACCESS_ONCE(lock->tickets);
>+      if (tmp.tickets.head != tmp.tickets.tail)
>+              return 0;
>+
>+      new.slock = tmp.slock + (1 << TICKET_SHIFT);
>+
>+      ret = cmpxchg(&lock->ticketpair, tmp.slock, new.slock) == tmp.slock;
>+      barrier();              /* just make nothing creeps before lock is 
>claimed */

This one should be smp_wmb(), right? No CONFIG_X86_OOSTORE protected.

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

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