From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933939AbXCTXeN (ORCPT ); Tue, 20 Mar 2007 19:34:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933933AbXCTXeM (ORCPT ); Tue, 20 Mar 2007 19:34:12 -0400 Received: from gw.goop.org ([64.81.55.164]:48170 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933926AbXCTXeL (ORCPT ); Tue, 20 Mar 2007 19:34:11 -0400 Message-ID: <46006F66.4030901@goop.org> Date: Tue, 20 Mar 2007 16:33:58 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Zachary Amsden CC: Matt Mackall , Linus Torvalds , "Eric W. Biederman" , Rusty Russell , Andi Kleen , David Miller , mingo@elte.hu, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, virtualization@lists.osdl.org, xen-devel@lists.xensource.com, chrisw@sous-sol.org, anthony@codemonkey.ws, netdev@vger.kernel.org Subject: Re: [patch 13/26] Xen-paravirt_ops: Consistently wrap paravirt ops callsites to make them patchable References: <1174272469.11680.23.camel@localhost.localdomain> <1174348905.11680.54.camel@localhost.localdomain> <45FF4043.4000805@vmware.com> <45FF770C.7050301@goop.org> <46000C7E.4070001@goop.org> <20070320224324.GL10459@waste.org> <46006963.1020401@vmware.com> In-Reply-To: <46006963.1020401@vmware.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Zachary Amsden wrote: > I think Jeremy's idea was to have interrupt handlers leave interrupts > disabled on exit if pda.intr_mask was set. In which case, they would > bypass all work and we could never get preempted. Yes, I was worried that if we left the isr without actually handling the interrupt, it would still be asserted and we'd just get interrupted again. The idea is that we avoid touching cli/sti for the common case of no interrupts while interrupts are disabled, but we'd still need to fall back to using them if an interrupt becomes pending. > I don't think leaving hardware interrupts disabled for such a long > time is good though. How long? It would be no longer than now, and possibly less, wouldn't it? J