From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 26 May 2002 04:16:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 26 May 2002 04:15:59 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:49733 "EHLO frodo.biederman.org") by vger.kernel.org with ESMTP id ; Sun, 26 May 2002 04:15:58 -0400 To: Andrea Arcangeli Cc: Alexander Viro , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: negative dentries wasting ram In-Reply-To: <20020524163942.GB15703@dualathlon.random> <20020524175522.GD15703@dualathlon.random> From: ebiederm@xmission.com (Eric W. Biederman) Date: 26 May 2002 02:06:55 -0600 Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.1 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrea Arcangeli writes: > > Anyways in 2.5 we could still take advantage of the negative dentries as > much as possible (also after unlink) by moving the negative dentries > into a separate list and by putting the shrinkage of this list in front > of kmem_cache_reap, so we are as efficient as possible, but we don't > risk throwing away very useful cache, for more dubious caching effects > after an unlink/create-failure that currently have the side effect of > throwing away tons of worthwhile positive pagecache (and even triggering > swap false positives) in some workloads. Right treat the new never referenced negative dentries as second class citizens until someone comes along and uses them, instead of aged useful cache entries. This sounds like a very good solution to this. Eric