Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756220AbYGGQa7 (ORCPT ); Mon, 7 Jul 2008 12:30:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754104AbYGGQai (ORCPT ); Mon, 7 Jul 2008 12:30:38 -0400 Received: from one.firstfloor.org ([213.235.205.2]:39301 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754287AbYGGQai (ORCPT ); Mon, 7 Jul 2008 12:30:38 -0400 Date: Mon, 7 Jul 2008 18:43:03 +0200 From: Andi Kleen To: Vitaly Mayatskikh Cc: Linus Torvalds , Andi Kleen , linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [PATCH 1/2] Introduce copy_user_handle_tail routine Message-ID: <20080707164303.GD20428@one.firstfloor.org> References: <486B8B6C.2050109@firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 764 Lines: 21 On Mon, Jul 07, 2008 at 02:12:56PM +0200, Vitaly Mayatskikh wrote: > Vitaly Mayatskikh writes: > > >> one), by limiting the byte-for-byte one to be within a page, but that > >> would be a "future enhancement" thing. > > > > Btw, how much does it cost to CPU to do a fault? Can it be compared with > > average time of find_vma()? > > Remark: this is for preventing fault in memset, not byte-to-byte copy. memset never faults. The current code doesn't handle it and it never happened. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/