Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754183Ab0FYCEY (ORCPT ); Thu, 24 Jun 2010 22:04:24 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:47910 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751270Ab0FYCEX (ORCPT ); Thu, 24 Jun 2010 22:04:23 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Nathan Fontenot Subject: Re: [PATCH] memory hotplug disable boot option Cc: kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org In-Reply-To: <4C24012B.9030506@austin.ibm.com> References: <4C24012B.9030506@austin.ibm.com> Message-Id: <20100625105340.803C.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Fri, 25 Jun 2010 11:04:19 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1703 Lines: 55 > Proposed patch to disable memory hotplug via a boot option, > mem_hotplug=[on|off]. The patch only disables memory hotplug in that it > prevents the creation of the memory sysfs directories for memory sections. > > This patch is meant to help alleviate very long boot times on systems with > large memory (1+ TB) and many memory sections (10's of thousands). Why making simple /sys file is so slowly? Couldn't we fix such performance problem? > > Signed-off-by: Nathan Fontenot > > --- > drivers/base/memory.c | 33 +++++++++++++++++++++++++++++++++ > drivers/base/node.c | 3 +++ > include/linux/memory.h | 2 ++ > 3 files changed, 38 insertions(+) > > Index: linux-2.6/drivers/base/memory.c > =================================================================== > --- linux-2.6.orig/drivers/base/memory.c 2010-06-23 15:07:03.000000000 -0500 > +++ linux-2.6/drivers/base/memory.c 2010-06-24 18:46:52.000000000 -0500 > @@ -29,6 +29,24 @@ > > #define MEMORY_CLASS_NAME "memory" > > +static int mem_hp_enabled __read_mostly = 1; please don't use 'hp' acronym. 'hotplug' is not so long word. > + > +static int __setup_memory_hotplug(char *option) > +{ > + if (!strcmp(option, "off")) > + mem_hp_enabled = 0; > + else if (!strcmp(option, "on")) > + mem_hp_enabled = 1; > + > + return 1; > +} > +__setup("mem_hotplug=", __setup_memory_hotplug); no documentation on Documentation/kernel-parameters.txt? -- 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/