From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH RFC 10/12] x86/pvticketlock: keep count of
	blocked cpus
Date: Tue, 03 Aug 2010 10:32:40 +0200
Message-ID: <1280824360.1923.421.camel@laptop>
References: <cover.1279328276.git.jeremy.fitzhardinge@citrix.com>
	<9d5625e61c7f35e72156e8cb881e55910b4fa5dc.1279328276.git.jeremy.fitzhardinge@citrix.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Return-path: <xen-devel-bounces@lists.xensource.com>
In-Reply-To: <9d5625e61c7f35e72156e8cb881e55910b4fa5dc.1279328276.git.jeremy.fitzhardinge@citrix.com>
List-Unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Nick Piggin <npiggin@suse.de>, Xen-devel <xen-devel@lists.xensource.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Jan Beulich <JBeulich@novell.com>, Avi Kivity <avi@redhat.com>
List-Id: xen-devel@lists.xenproject.org

On Fri, 2010-07-16 at 18:03 -0700, Jeremy Fitzhardinge wrote:
> @@ -26,6 +26,9 @@ typedef struct arch_spinlock {
>                         __ticket_t head, tail;
>                 } tickets;
>         };
> +#ifdef CONFIG_PARAVIRT_SPINLOCKS
> +       __ticket_t waiting;
> +#endif
>  } arch_spinlock_t;=20

This bloats spinlock_t from u32 to u64 on most distro configs I think,
since they'll have NR_CPUS=3D4096 or something large like that and
probably also want to have this PARAVIRT_SPINLOCKS thing.