From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752134Ab2ISVXm (ORCPT ); Wed, 19 Sep 2012 17:23:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11803 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751787Ab2ISVXk (ORCPT ); Wed, 19 Sep 2012 17:23:40 -0400 Date: Tue, 18 Sep 2012 20:43:07 -0300 From: Marcelo Tosatti To: Xiao Guangrong Cc: Avi Kivity , LKML , KVM Subject: Re: [PATCH v2 4/5] KVM: MMU: introduce page_fault_start and page_fault_end Message-ID: <20120918234307.GA5062@amt.cnet> References: <5052FF61.3070600@linux.vnet.ibm.com> <5052FFEA.1040607@linux.vnet.ibm.com> <20120915152512.GB3037@amt.cnet> <50582DA4.8060000@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50582DA4.8060000@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 18, 2012 at 04:15:32PM +0800, Xiao Guangrong wrote: > On 09/15/2012 11:25 PM, Marcelo Tosatti wrote: > > On Fri, Sep 14, 2012 at 05:59:06PM +0800, Xiao Guangrong wrote: > >> Wrap the common operations into these two functions > >> > >> Signed-off-by: Xiao Guangrong > > > > Why? I think people are used to > > > > spin_lock(lock) > > sequence > > spin_unlock(lock) > > Marcelo, > > There are many functions use this style that wrap the lock into the > _start and _end functions in kernel (eg.: cgroup_pidlist_start and > cgroup_pidlist_stop in kernel/cgroup.c). > > Actually, i just wanted to remove below duplicate ugly code: > > if (!is_error_pfn(pfn)) > kvm_release_pfn_clean(pfn); > > > > > So its easy to verify whether access to data structures are protected. > > > > Unrelated to this patch, one opportunity i see to simplify this > > code is: > > > > - error pfn / mmio pfn / invalid pfn relation > > > > Have the meaning of this bits unified in a single function/helper, see > > comment to patch 1 (perhaps you can further improve). > > Sorry, more detail? Should force the reader of the code to understand error pfn / mmio pfn / invalid pfn in a single helper. That is, avoid using error pfn at all. > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html