Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752994Ab0L3IfX (ORCPT ); Thu, 30 Dec 2010 03:35:23 -0500 Received: from vuizook.err.no ([85.19.221.46]:37944 "EHLO vuizook.err.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751903Ab0L3IfW (ORCPT ); Thu, 30 Dec 2010 03:35:22 -0500 X-Greylist: delayed 2175 seconds by postgrey-1.27 at vger.kernel.org; Thu, 30 Dec 2010 03:35:22 EST Date: Thu, 30 Dec 2010 08:59:01 +0100 From: Mike Hommey To: linux-kernel@vger.kernel.org Subject: Containers and /proc/sys/vm/drop_caches Message-ID: <20101230075901.GA4115@glandium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-GPG-Fingerprint: A479 A824 265C B2A5 FC54 8D1E DE4B DA2C 54FD 2A58 User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 713 Lines: 19 Hi, I noticed that from within a lxc container, writing "3" to /proc/sys/vm/drop_caches would flush the host page cache. That sounds a little dangerous for VPS offerings that would be based on lxc, as in one VPS instance root user could impact the overall performance of the host. I don't know about other containers but I've been told openvz isn't subject to this problem. I only tested the current Debian Squeeze kernel, which is based on 2.6.32.27. Cheers, Mike -- 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/