From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx128.postini.com [74.125.245.128]) by kanga.kvack.org (Postfix) with SMTP id F2E0E6B00A4 for ; Mon, 15 Oct 2012 10:06:33 -0400 (EDT) Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 15 Oct 2012 10:06:32 -0400 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id E45B238C804F for ; Mon, 15 Oct 2012 10:06:29 -0400 (EDT) Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q9FE6TC6192424 for ; Mon, 15 Oct 2012 10:06:29 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q9FE6S30009669 for ; Mon, 15 Oct 2012 10:06:29 -0400 Message-ID: <507C183C.2070106@linux.vnet.ibm.com> Date: Mon, 15 Oct 2012 07:05:48 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [PATCH] add some drop_caches documentation and info messsge References: <20121012125708.GJ10110@dhcp22.suse.cz> In-Reply-To: <20121012125708.GJ10110@dhcp22.suse.cz> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, KAMEZAWA Hiroyuki , KOSAKI Motohiro , Andrew Morton , LKML On 10/12/2012 05:57 AM, Michal Hocko wrote: > I would like to resurrect the following Dave's patch. The last time it > has been posted was here https://lkml.org/lkml/2010/9/16/250 and there > didn't seem to be any strong opposition. > Kosaki was worried about possible excessive logging when somebody drops > caches too often (but then he claimed he didn't have a strong opinion > on that) but I would say opposite. If somebody does that then I would > really like to know that from the log when supporting a system because > it almost for sure means that there is something fishy going on. It is > also worth mentioning that only root can write drop caches so this is > not an flooding attack vector. Just read through the patch again. Still looks great to me. Thanks for bringing it up again, Michal! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753894Ab2JOOGi (ORCPT ); Mon, 15 Oct 2012 10:06:38 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:57274 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753686Ab2JOOGf (ORCPT ); Mon, 15 Oct 2012 10:06:35 -0400 Message-ID: <507C183C.2070106@linux.vnet.ibm.com> Date: Mon, 15 Oct 2012 07:05:48 -0700 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120912 Thunderbird/15.0.1 MIME-Version: 1.0 To: Michal Hocko CC: linux-mm@kvack.org, KAMEZAWA Hiroyuki , KOSAKI Motohiro , Andrew Morton , LKML Subject: Re: [PATCH] add some drop_caches documentation and info messsge References: <20121012125708.GJ10110@dhcp22.suse.cz> In-Reply-To: <20121012125708.GJ10110@dhcp22.suse.cz> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12101514-7182-0000-0000-000002D3E30C Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/12/2012 05:57 AM, Michal Hocko wrote: > I would like to resurrect the following Dave's patch. The last time it > has been posted was here https://lkml.org/lkml/2010/9/16/250 and there > didn't seem to be any strong opposition. > Kosaki was worried about possible excessive logging when somebody drops > caches too often (but then he claimed he didn't have a strong opinion > on that) but I would say opposite. If somebody does that then I would > really like to know that from the log when supporting a system because > it almost for sure means that there is something fishy going on. It is > also worth mentioning that only root can write drop caches so this is > not an flooding attack vector. Just read through the patch again. Still looks great to me. Thanks for bringing it up again, Michal!