Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030363AbWL3Wpy (ORCPT ); Sat, 30 Dec 2006 17:45:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030364AbWL3Wpy (ORCPT ); Sat, 30 Dec 2006 17:45:54 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:46129 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030363AbWL3Wpy (ORCPT ); Sat, 30 Dec 2006 17:45:54 -0500 Subject: Re: replace "memset(...,0,PAGE_SIZE)" calls with "clear_page()"? From: Arjan van de Ven To: "Robert P. J. Day" Cc: Denis Vlasenko , Linux kernel mailing list In-Reply-To: References: <200612302149.35752.vda.linux@googlemail.com> Content-Type: text/plain Organization: Intel International BV Date: Sat, 30 Dec 2006 23:45:48 +0100 Message-Id: <1167518748.20929.578.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.8.2.1 (2.8.2.1-2.fc6) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 976 Lines: 24 > i don't see how that can be true, given that most of the definitions > of the clear_page() macro are simply invocations of memset(). see for > yourself: *MOST*. Not all. For example an SSE version will at least assume 16 byte alignment, etc etc. clear_page() is supposed to be for full real pages only... for example it allows the architecture to optimize for alignment, cache aliasing etc etc. (and if there are cpus that get a "clear an entire page" instruction.... there has been hardware like that in the past, even on x86, just it's no longer sold afaik) -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org - 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/