From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752819AbaABV65 (ORCPT ); Thu, 2 Jan 2014 16:58:57 -0500 Received: from mail-gg0-f173.google.com ([209.85.161.173]:59895 "EHLO mail-gg0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750822AbaABV6z (ORCPT ); Thu, 2 Jan 2014 16:58:55 -0500 Date: Thu, 2 Jan 2014 13:58:52 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Dave Hansen cc: linux-kernel@vger.kernel.org, Andrea Arcangeli , Mel Gorman , Andrew Morton , linux-mm@kvack.org, Michal Hocko Subject: Re: [RFC] mm: show message when updating min_free_kbytes in thp In-Reply-To: <52C5AA61.8060701@intel.com> Message-ID: References: <20140101002935.GA15683@localhost.localdomain> <52C5AA61.8060701@intel.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2 Jan 2014, Dave Hansen wrote: > > min_free_kbytes may be updated during thp's initialization. Sometimes, > > this will change the value being set by user. Showing message will > > clarify this confusion. > ... > > - if (recommended_min > min_free_kbytes) > > + if (recommended_min > min_free_kbytes) { > > min_free_kbytes = recommended_min; > > + pr_info("min_free_kbytes is updated to %d by enabling transparent hugepage.\n", > > + min_free_kbytes); > > + } > > "updated" doesn't tell us much. It's also kinda nasty that if we enable > then disable THP, we end up with an elevated min_free_kbytes. Maybe we > should at least put something in that tells the user how to get back > where they were if they care: > The default value of min_free_kbytes depends on the implementation of the VM regardless of any config options that you may have enabled. We don't specify what the non-thp default is in the kernel log, so why do we need to specify what the thp default is?