From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755898AbZCRXhl (ORCPT ); Wed, 18 Mar 2009 19:37:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751976AbZCRXhc (ORCPT ); Wed, 18 Mar 2009 19:37:32 -0400 Received: from gw.goop.org ([64.81.55.164]:44908 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751955AbZCRXhb (ORCPT ); Wed, 18 Mar 2009 19:37:31 -0400 Message-ID: <49C185B4.90004@goop.org> Date: Wed, 18 Mar 2009 16:37:24 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Shentino CC: Avi Kivity , Nick Piggin , Linux Kernel Mailing List , Linux Memory Management List , Xen-devel , Jan Beulich , Ingo Molnar Subject: Re: Question about x86/mm/gup.c's use of disabled interrupts References: <49C148AF.5050601@goop.org> <49C16411.2040705@redhat.com> <49C1665A.4080707@goop.org> <49C16A48.4090303@redhat.com> <49C17230.20109@goop.org> <49C17880.7080109@redhat.com> <49C17BD8.6050609@goop.org> <49C17E22.9040807@redhat.com> <70513aa50903181617r418ec23s744544dccfd812e8@mail.gmail.com> In-Reply-To: <70513aa50903181617r418ec23s744544dccfd812e8@mail.gmail.com> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Shentino wrote: > But, does a CPU running a task in userspace effectively have a read > lock on the page tables? No. A process has its own user pagetable which the kernel maintains on its behalf. The kernel will briefly take locks on it while doing modifications, mostly to deal with multithreaded usermode code running on multiple cpus. J From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 45DED6B003D for ; Wed, 18 Mar 2009 19:37:32 -0400 (EDT) Message-ID: <49C185B4.90004@goop.org> Date: Wed, 18 Mar 2009 16:37:24 -0700 From: Jeremy Fitzhardinge MIME-Version: 1.0 Subject: Re: Question about x86/mm/gup.c's use of disabled interrupts References: <49C148AF.5050601@goop.org> <49C16411.2040705@redhat.com> <49C1665A.4080707@goop.org> <49C16A48.4090303@redhat.com> <49C17230.20109@goop.org> <49C17880.7080109@redhat.com> <49C17BD8.6050609@goop.org> <49C17E22.9040807@redhat.com> <70513aa50903181617r418ec23s744544dccfd812e8@mail.gmail.com> In-Reply-To: <70513aa50903181617r418ec23s744544dccfd812e8@mail.gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Shentino Cc: Avi Kivity , Nick Piggin , Linux Kernel Mailing List , Linux Memory Management List , Xen-devel , Jan Beulich , Ingo Molnar List-ID: Shentino wrote: > But, does a CPU running a task in userspace effectively have a read > lock on the page tables? No. A process has its own user pagetable which the kernel maintains on its behalf. The kernel will briefly take locks on it while doing modifications, mostly to deal with multithreaded usermode code running on multiple cpus. J -- 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