From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753231Ab0CSB3L (ORCPT ); Thu, 18 Mar 2010 21:29:11 -0400 Received: from mail-yw0-f172.google.com ([209.85.211.172]:49001 "EHLO mail-yw0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752407Ab0CSB3J (ORCPT ); Thu, 18 Mar 2010 21:29:09 -0400 X-Greylist: delayed 4687 seconds by postgrey-1.27 at vger.kernel.org; Thu, 18 Mar 2010 21:29:09 EDT DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=nfp4RlOcUSwQ3XHMgT5ltDFBveFgfEtHZ62GZB2HZKBuuCbZOZProd30VjTY3BDfHC wXUHd1sHS8DqSHn7HXXv9Yk/WMLFyNoiUfoiPsOtHDCEGLoPcH6i8Yj+kf7kkyghhJWu NCcb+zFhOtTnLwy3f/Y2BfD2XCj40rS6hkVZo= MIME-Version: 1.0 In-Reply-To: <3e8340491003181806t201218acod8ea408d1993cbfc@mail.gmail.com> References: <21512362.post@talk.nabble.com> <3e8340490901162016y268e3936k4b2d3fcb2afcf216@mail.gmail.com> <21512985.post@talk.nabble.com> <3e8340490901162126u109da9cbu7292fddf6d832723@mail.gmail.com> <49f90a801003181710v5e08ccc8jdd26ec899e75bdb9@mail.gmail.com> <3e8340491003181728r766245edo91ecc1db75f3a6df@mail.gmail.com> <49f90a801003181747m5078d9c2y3cc8421203a7b1e6@mail.gmail.com> <3e8340491003181806t201218acod8ea408d1993cbfc@mail.gmail.com> Date: Thu, 18 Mar 2010 21:29:07 -0400 Message-ID: <49f90a801003181829w63b3e96fp79c015b15b8d535b@mail.gmail.com> Subject: Re: Kernel vs user memory From: Siddhartha Chhabra To: Bryan Donlan Cc: LKML Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 18, 2010 at 9:06 PM, Bryan Donlan wrote: > > That is correct. The kernel can avoid a PF if it wants to by ensuring > the page tables are set up properly from the start; and physical > addresses below a certain value (which varies by architecture) can be > accessed directly without any setup at all. > Thank you for your time, this discussion was really helpful. Thanks once again Sid