From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: [patch 14/26] Xen-paravirt_ops: add common patching machinery Date: Sat, 17 Mar 2007 20:15:36 +1100 Message-ID: <1174122936.8897.21.camel@localhost.localdomain> References: <20070301232443.195603797@goop.org> <20070301232528.055105942@goop.org> <20070316092054.GK23174@elte.hu> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20070316092054.GK23174@elte.hu> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ingo Molnar Cc: Zachary Amsden , Jeremy Fitzhardinge , xen-devel@lists.xensource.com, Andi Kleen , linux-kernel@vger.kernel.org, Chris Wright , virtualization@lists.osdl.org, Anthony Liguori , Andrew Morton List-Id: virtualization@lists.linuxfoundation.org On Fri, 2007-03-16 at 10:20 +0100, Ingo Molnar wrote: > * Jeremy Fitzhardinge wrote: > > > Implement the actual patching machinery. paravirt_patch_default() > > contains the logic to automatically patch a callsite based on a few > > simple rules: > > > > - if the paravirt_op function is paravirt_nop, then patch nops > > - if the paravirt_op function is a jmp target, then jmp to it > > - if the paravirt_op function is callable and doesn't clobber too much > > for the callsite, call it directly > > > > paravirt_patch_default is suitable as a default implementation of > > paravirt_ops.patch, will remove most of the expensive indirect calls > > in favour of either a direct call or a pile of nops. > > Acked-by: Ingo Molnar I like this one too, but note that it needs a twist when we change to use direct calls to wrappers for the Great paravirt_ops Unexporting. Rusty.