From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 1 Sep 2010 07:57:45 +1000 From: Anton Blanchard To: Nathan Fontenot Subject: Re: [PATCH 0/8] v5 De-couple sysfs memory directories from memory sections Message-ID: <20100831215745.GA7641@kryten> References: <4C60407C.2080608@austin.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <4C60407C.2080608@austin.ibm.com> Cc: linuxppc-dev@ozlabs.org, Greg KH , linux-kernel@vger.kernel.org, Dave Hansen , linux-mm@kvack.org, akpm@linux-foundation.org, KAMEZAWA Hiroyuki List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Nathan, > This set of patches de-couples the idea that there is a single > directory in sysfs for each memory section. The intent of the > patches is to reduce the number of sysfs directories created to > resolve a boot-time performance issue. On very large systems > boot time are getting very long (as seen on powerpc hardware) > due to the enormous number of sysfs directories being created. > On a system with 1 TB of memory we create ~63,000 directories. > For even larger systems boot times are being measured in hours. > > This set of patches allows for each directory created in sysfs > to cover more than one memory section. The default behavior for > sysfs directory creation is the same, in that each directory > represents a single memory section. A new file 'end_phys_index' > in each directory contains the physical_id of the last memory > section covered by the directory so that users can easily > determine the memory section range of a directory. I tested this on a POWER7 with 2TB memory and the boot time improved from greater than 6 hours (I gave up), to under 5 minutes. Nice! Tested-by: Anton Blanchard Anton