| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
[Xen-devel] Re: [PATCH 03/20] x86/ticketlock: Use C for __ticket_spin_un
|
To: |
Jeremy Fitzhardinge <jeremy@xxxxxxxx> |
|
Subject: |
[Xen-devel] Re: [PATCH 03/20] x86/ticketlock: Use C for __ticket_spin_unlock |
|
From: |
Américo Wang <xiyou.wangcong@xxxxxxxxx> |
|
Date: |
Sat, 13 Nov 2010 18:05:27 +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 01:21:40 -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=Pmn4dYMVq9j9jwDN/vMsSNMhJ/jvdMo782RLgs9nVEk=; b=fp7GuqdmCay92bBE5p11Ngo/zQmKtsqafKqV7XfFcWxos5GAmcne5cIFVE5YDc4zwg DBzcvHDjwy5NJLMbMDrUehXh1h5s8VWxuzoA2745NIm2gga8yQoKbqJQjpEE795ZQstr ydPpVfM7ifHiZY0Uzwxpx8ZUGKnf95u5DQ/AM= |
|
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=Xdlrpn3MIB+cEJZBuc16JFcsPJZuzknmEnsqyXXvahnOOJrVCKMl0hQWeIxjPLHqZi ndt1K6SJxMvQOeIURusBz8DXnm3eTddW7KDyhNbMErePNdc5FA4WhnrM9xDOry2u/gTE ZSSfQn1dSrsDBHafhKrO387ws++MO7LsRa0eo= |
|
Envelope-to: |
www-data@xxxxxxxxxxxxxxxxxxx |
|
In-reply-to: |
<20092775a9df07a5a75820ac250194b535279d51.1288794124.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> <20092775a9df07a5a75820ac250194b535279d51.1288794124.git.jeremy.fitzhardinge@xxxxxxxxxx> |
|
Sender: |
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
|
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Wed, Nov 03, 2010 at 10:59:44AM -0400, Jeremy Fitzhardinge wrote:
> * On PPro SMP or if we are using OOSTORE, we use a locked operation to unlock
> * (PPro errata 66, 92)
> */
>-# define UNLOCK_LOCK_PREFIX LOCK_PREFIX
>+static __always_inline void __ticket_unlock_release(struct arch_spinlock
>*lock)
>+{
>+ if (sizeof(lock->tickets.head) == sizeof(u8))
>+ asm (LOCK_PREFIX "incb %0"
>+ : "+m" (lock->tickets.head) : : "memory");
>+ else
>+ asm (LOCK_PREFIX "incw %0"
>+ : "+m" (lock->tickets.head) : : "memory");
This 'if/else' really should be done with #ifdef, even though
the compiler may be smart enough to remove it.
>+
>+}
> #else
>-# define UNLOCK_LOCK_PREFIX
>+static __always_inline void __ticket_unlock_release(struct arch_spinlock
>*lock)
>+{
>+ barrier();
>+ lock->tickets.head++;
>+ barrier();
The second barrier() is not needed.
Thanks.
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home