From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758705AbYEGQcv (ORCPT ); Wed, 7 May 2008 12:32:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752691AbYEGQce (ORCPT ); Wed, 7 May 2008 12:32:34 -0400 Received: from ti-out-0910.google.com ([209.85.142.185]:17193 "EHLO ti-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752257AbYEGQca (ORCPT ); Wed, 7 May 2008 12:32:30 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=aha83jdzFX//m4lc9hUlFsTxLpNFMAdUBRW7kbzcUOriRJ0SyvsO/R7Bz7WqHAV0GP5hbXeBw9bAKpdJpV+WOYnHm7qVJFh+7vA4vQsmnmTjUoxRraWyNeekgJWLL2v55CB852fTzZvVvsb+4hrwTJ2/vlokRhXXDH3Ob1BJpyU= Message-ID: <91b13c310805070932s439ce4bbsfe0d658c406b55c7@mail.gmail.com> Date: Thu, 8 May 2008 00:32:28 +0800 From: "rae l" To: "Ray Lee" Subject: Re: It's time to hack on dentry_stat? Cc: "Matthew Wilcox" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <2c0942db0805070910w6b304d3cye8848d5c03462aa2@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <91b13c310805070726k7eb1384ex7d557b5dca4b567@mail.gmail.com> <20080507145116.GV19219@parisc-linux.org> <2c0942db0805070808t663eafffic5e78c9d1ba8bc68@mail.gmail.com> <20080507152533.GW19219@parisc-linux.org> <2c0942db0805070910w6b304d3cye8848d5c03462aa2@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 8, 2008 at 12:10 AM, Ray Lee wrote: > Well, if there's one, then obviously there isn't. I'd assumed > it was a per-dentry overhead. Good. If the binary application interface must be kept, > $ cat /proc/sys/fs/dentry-state > 122104 115846 45 0 0 0 and to shrink dentry_stat can only save 16 bytes, there's no need to do this, but the Documentation/ as this should be fixed? Documentation/filesystems/proc.txt: dentry-state ------------ Status of the directory cache. Since directory entries are dynamically allocated and deallocated, this file indicates the current status. It holds six values, in which the last two are not used and are always zero. The others are listed in table 2-1. Table 2-1: Status files of the directory cache .............................................................................. File Content nr_dentry Almost always zero nr_unused Number of unused cache entries age_limit in seconds after the entry may be reclaimed, when memory is short want_pages internally .............................................................................. the age_limit and want_pages should be marked outdated and not used anymore, But there's still one question: 1. Is age_limit always 45? Or the binary application interface would expect it always 45? Can we change dentry_stat with 6 int values all initialized with zero? Then the docs can be fixed with last four values not used and are always zero. -- Cheng