From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [patch 13/26] Xen-paravirt_ops: Consistently wrap paravirt ops callsites to make them patchable Date: Tue, 20 Mar 2007 16:33:58 -0700 Message-ID: <46006F66.4030901@goop.org> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: xen-devel@lists.xensource.com, akpm@linux-foundation.org, virtualization@lists.osdl.org, netdev@vger.kernel.org, Rusty Russell , linux-kernel@vger.kernel.org, chrisw@sous-sol.org, Andi Kleen , "Eric W. Biederman" , anthony@codemonkey.ws, Matt Mackall , mingo@elte.hu, Linus Torvalds , David Miller To: Zachary Amsden Return-path: In-Reply-To: <46006963.1020401@vmware.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com List-Id: netdev.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