From mboxrd@z Thu Jan 1 00:00:00 1970 From: Don Porter Subject: ext3 leaking buffer_heads Date: Mon, 23 Mar 2009 14:56:09 -0500 Message-ID: <49C7E959.4010000@cs.utexas.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: linux-ext4@vger.kernel.org Return-path: Received: from mail.cs.utexas.edu ([128.83.139.10]:38757 "EHLO mail.cs.utexas.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755028AbZCWUpz (ORCPT ); Mon, 23 Mar 2009 16:45:55 -0400 Received: from [128.83.122.94] (habals.csres.utexas.edu [128.83.122.94]) (authenticated bits=0) by mail.cs.utexas.edu (8.14.3/8.14.3) with ESMTP id n2NJu9Qw011006 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 23 Mar 2009 14:56:10 -0500 (CDT) Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi, It appears that the ext3 journal code has a slow leak of buffer_head structs. Try this simple script: perl -e 'while(1){ `sync`; }' and monitor the count of allocated buffer_head structs in /proc/slabinfo, and it seems to increase without bound. Even after this script is killed and the machine is left idle for several minutes, the count of buffer heads doesn't substantially decrease. Looking around at various machines I have access to, the count of allocated buffer_heads roughly correlates with uptime when using ext3. This is a slow leak - one would likely have to run this script for a day or more to drain enough lowmem to cause problems. Other info: I have only tried this on x86 machines, but I have tried both 2.6.22.6 and 2.6.28.8, and both have the problem. I am running Ubuntu 7.10 on top of these kernels, but the kernels were built directly from kernel.org tarballs. Any advice or help with this issue is greatly appreciated. Thanks, Don