From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753858AbZHZVWY (ORCPT ); Wed, 26 Aug 2009 17:22:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753367AbZHZVWY (ORCPT ); Wed, 26 Aug 2009 17:22:24 -0400 Received: from mail-qy0-f198.google.com ([209.85.221.198]:61016 "EHLO mail-qy0-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753310AbZHZVWX (ORCPT ); Wed, 26 Aug 2009 17:22:23 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=BfRNM0aeFqNPYPcfrSJwln9G86sn1UdakBgDzll3uJvWhaBJex1660lBYxqgIQw/ZE WEf1cIe9nI44PQTm6DWHs91hkN2EGnzTfciekditlASNlvXFi3QpYkWO0oSSZTcpTogi W8MpyyswU8PKXBPXJguGfPaRIJwtRLXzkehIA= MIME-Version: 1.0 Date: Wed, 26 Aug 2009 14:22:24 -0700 Message-ID: <689eb3470908261422u50e59d9ex1a3c43fdc2f3d4e8@mail.gmail.com> Subject: Differentiating clean and dirty buffer cache pages From: Anupama Chandwani To: linux kernel mailing list , Linus Torvalds , Andrew Morton Cc: Krishna Raj Raja , vrajesh@vmware.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I need to get stats about what pages in the buffer cache are clean versus dirty. I traverse the page_tree pointer of the radix tree of each open file to get all buffer cache pages. To identify dirty pages, I think of doing the following: Level 1. Do a gang lookup in radix tree for PAGECACHE_TAG_DIRTY tag, Level 2. Check the PTE of buffer cache pages for bit 6(D) I want to know if checking these two data structures will give me a complete list of all the dirty pages in the buffer cache? -- Cheers, Anupama Chandwani