Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758379AbZGHSG2 (ORCPT ); Wed, 8 Jul 2009 14:06:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754817AbZGHSGW (ORCPT ); Wed, 8 Jul 2009 14:06:22 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:46098 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754007AbZGHSGW (ORCPT ); Wed, 8 Jul 2009 14:06:22 -0400 Date: Wed, 08 Jul 2009 11:06:24 -0700 (PDT) Message-Id: <20090708.110624.104984745.davem@davemloft.net> To: michal.simek@petalogix.com Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@elte.hu, arnd@arndb.de, lethal@linux-sh.org, ltp-list@lists.sourceforge.net Subject: Re: mmap hw behavior From: David Miller In-Reply-To: <4A54DF6F.1010405@petalogix.com> References: <4A54D14F.9090101@petalogix.com> <20090708.103520.193697491.davem@davemloft.net> <4A54DF6F.1010405@petalogix.com> X-Mailer: Mew version 6.2.51 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1307 Lines: 31 From: Michal Simek Date: Wed, 08 Jul 2009 20:03:27 +0200 > David Miller wrote: >> From: Michal Simek >> Date: Wed, 08 Jul 2009 19:03:11 +0200 >> >> >>> When I call mmap for that open file with pointer to calloc place >>> (first parameter, + length zero) it should be one tlb invalidation >>> for calloc and new tlb which connect open file. We check it and we >>> don't have any tlb invalidation that's why I think that kernel do >>> different thigs. Or is it there any copying? Or anything different? >>> >> >> There is no need to tlb flush the calloc area unless that memory area >> is actually touched by the user application and thus the page is >> faulted in. >> > That calloc area is filled by any value (in that test). Is it mean that > for this case when calloc area is touched > there must be tlb invalidation + remapping? Yes, if the calloc area is written to by the application, there should be a tlb flush when the mmap() overrides that virtual region with a different mapping. -- 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/