From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx163.postini.com [74.125.245.163]) by kanga.kvack.org (Postfix) with SMTP id 4D9D96B0005 for ; Tue, 26 Feb 2013 07:45:43 -0500 (EST) Message-ID: <1361882727.3235.14.camel@thor.lan> Subject: Re: [PATCH 0/5] [v3] fix illegal use of __pa() in KVM code From: Peter Hurley Date: Tue, 26 Feb 2013 07:45:27 -0500 In-Reply-To: <512B784E.5070002@linux.vnet.ibm.com> References: <20130122212428.8DF70119@kernel.stglabs.ibm.com> <1361741338.21499.38.camel@thor.lan> <512B784E.5070002@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Gleb Natapov , "H. Peter Anvin" , x86@kernel.org, Marcelo Tosatti , Rik van Riel On Mon, 2013-02-25 at 06:42 -0800, Dave Hansen wrote: > On 02/24/2013 01:28 PM, Peter Hurley wrote: > > Now that the alloc_remap() has been/is being removed, is most/all of > > this being reverted? > > I _believe_ alloc_remap() is the only case where we actually remapped > low memory. However, there is still other code that does __pa() > translations for percpu areas: per_cpu_ptr_to_phys(). I _think_ it's > still theoretically possible to get some percpu data in the vmalloc() area. > > > So in short, my questions are: > > 1) is the slow_virt_to_phys() necessary anymore? Ah, yep. Thanks for pointing out per_cpu_ptr_to_phys(). > kvm_vcpu_arch has a > > struct pvclock_vcpu_time_info hv_clock; > > and I believe I mistook the two 'hv_clock's for each other. However, > this doesn't hurt anything, and the performance difference is probably > horribly tiny. Ok. It was confusing because the fixmap of that same phys memblock done by pvclock was broken and I couldn't understand why the hvclock memblock needed to be looked-up per cpu. Mystery solved. Regards, Peter Hurley -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org