Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756792Ab3G3PYs (ORCPT ); Tue, 30 Jul 2013 11:24:48 -0400 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:47237 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756632Ab3G3PXq (ORCPT ); Tue, 30 Jul 2013 11:23:46 -0400 Date: Fri, 26 Jul 2013 09:33:44 -0500 From: Seth Jennings To: Greg Kroah-Hartman 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: <20130726143344.GA4379@variantweb.net> References: <1374786680-26197-1-git-send-email-sjenning@linux.vnet.ibm.com> <20130725233800.GA18349@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130725233800.GA18349@kroah.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13073015-9574-0000-0000-000008F3DECB Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2007 Lines: 43 On Thu, Jul 25, 2013 at 04:38:00PM -0700, Greg Kroah-Hartman wrote: > 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? So this patch introduces the new layout in a new file drives/base/memfs.c (which, in light of your last comment should probably be something more like largememory.c). It doesn't clash with Nathan's, but it doesn't contain the new is_memblock_[removable|offline] functions or the new "release" attribute. But that can be added easily. Seth -- 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/