From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <jbeulich@novell.com>
Subject: Re: linux: {start, stop}_hz_timer() not really
	affecting periodic timer?
Date: Wed, 16 Jan 2008 17:17:38 +0000
Message-ID: <478E4A42.76E4.0078.0@novell.com>
References: <478E4095.76E4.0078.0@novell.com>
	<C3B3E562.1AEAE%Keir.Fraser@cl.cam.ac.uk>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: quoted-printable
Return-path: <xen-devel-bounces@lists.xensource.com>
In-Reply-To: <C3B3E562.1AEAE%Keir.Fraser@cl.cam.ac.uk>
Content-Disposition: inline
List-Unsubscribe: <http://lists.xensource.com/cgi-bin/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/cgi-bin/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: Keir Fraser <Keir.Fraser@cl.cam.ac.uk>
Cc: xen-devel@lists.xensource.com
List-Id: xen-devel@lists.xenproject.org

>>> Keir Fraser <Keir.Fraser@cl.cam.ac.uk> 16.01.08 17:46 >>>
>On 16/1/08 16:36, "Jan Beulich" <jbeulich@novell.com> wrote:
>
>>> If the time is in the past then the singleshot timer will fire =
immediately.
>>> So you'll take a slower path than necessary, but the code as-is will =
work
>>> fine.
>>=20
>> Immediately would mean to me that it would fire on the return path
>> from VCPUOP_set_singleshot_timer, so HYPERVISOR_block() would
>> not (necessarily) find any pending events and hence block when it
>> shouldn't. Or am I missing some magic by which this is being avoided?
>
>The function should only be called with interrupts disabled.

That goes back to what I stated first - there's nothing really requiring
this, it just happens to be that way at present.

Jan