Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755287Ab3GYXiE (ORCPT ); Thu, 25 Jul 2013 19:38:04 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40559 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752418Ab3GYXiC (ORCPT ); Thu, 25 Jul 2013 19:38:02 -0400 Date: Thu, 25 Jul 2013 16:38:00 -0700 From: Greg Kroah-Hartman To: Seth Jennings Cc: Nathan Fontenot , Andrew Morton , "Rafael J. Wysocki" , Nivedita Singhvi , Michael J Wolf , linux-kernel@vger.kernel.org Subject: Re: [PATCH] drivers: base: new memory config sysfs driver for large memory systems Message-ID: <20130725233800.GA18349@kroah.com> References: <1374786680-26197-1-git-send-email-sjenning@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1374786680-26197-1-git-send-email-sjenning@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1562 Lines: 35 On Thu, Jul 25, 2013 at 04:11:20PM -0500, Seth Jennings wrote: > From: Nathan Fontenot > > Large memory systems (1TB or more) experience boot delays on the order > of minutes due to the initializing the memory configuration part of > sysfs at /sys/devices/system/memory/. > > ppc64 has a memory block size of 256M and (I think) x86 is 128M. With 1TB > of RAM and a 256M block size, that's 4k memory blocks with 20 sysfs > entries per block that's around 80k items that need be created at boot > time in sysfs. Some systems go up to 16TB where the issue is > even more severe. > > This patch is a prototype for a new sysfs memory layout where the > entries are created on demand by writing memory block numbers into a > "show" and "hide" files to create and destroy the memory block > configuration attributes in sysfs. This would decouple the number of > sysfs entries created at boot time from the memory size, resulting in a > sysfs initialization time that doesn't increase and memory size > increase. > > Signed-off-by: Seth Jennings > Signed-off-by: Nathan Fontenot How does this tie into the patches Nathan sent yesterday for memory hotplug stuff that I thought modified the same part of the kernel? thanks, greg k-h -- 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/