From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751701Ab1ATQvs (ORCPT ); Thu, 20 Jan 2011 11:51:48 -0500 Received: from e34.co.us.ibm.com ([32.97.110.152]:58533 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750712Ab1ATQvr (ORCPT ); Thu, 20 Jan 2011 11:51:47 -0500 Message-ID: <4D386820.5080902@austin.ibm.com> Date: Thu, 20 Jan 2011 10:51:44 -0600 From: Nathan Fontenot User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101208 Thunderbird/3.1.7 MIME-Version: 1.0 To: Greg KH CC: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, KAMEZAWA Hiroyuki , Robin Holt Subject: Re: [PATCH 0/4] De-couple sysfs memory directories from memory sections References: <4D386498.9080201@austin.ibm.com> <20110120164555.GA30922@kroah.com> In-Reply-To: <20110120164555.GA30922@kroah.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/20/2011 10:45 AM, Greg KH wrote: > On Thu, Jan 20, 2011 at 10:36:40AM -0600, Nathan Fontenot wrote: >> The root of this issue is in sysfs directory creation. Every time >> a directory is created a string compare is done against sibling >> directories ( see sysfs_find_dirent() ) to ensure we do not create >> duplicates. The list of directory nodes in sysfs is kept as an >> unsorted list which results in this being an exponentially longer >> operation as the number of directories are created. > > Again, are you sure about this? I thought we resolved this issue in the > past, but you were going to check it. Did you? > Yes, the string compare is still present in the sysfs code. There was discussion around this sometime last year when I sent a patch out that stored the directory entries in something other than a linked list. That patch was rejected but it was agreed that something should be done. -Nathan From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id D29BF8D003A for ; Thu, 20 Jan 2011 11:51:48 -0500 (EST) Received: from d01dlp02.pok.ibm.com (d01dlp02.pok.ibm.com [9.56.224.85]) by e6.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p0KGbJqE021423 for ; Thu, 20 Jan 2011 11:37:20 -0500 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id 3D1564DE803B for ; Thu, 20 Jan 2011 11:48:27 -0500 (EST) Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p0KGpkpx472110 for ; Thu, 20 Jan 2011 11:51:46 -0500 Received: from d03av05.boulder.ibm.com (loopback [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p0KGpja2028708 for ; Thu, 20 Jan 2011 09:51:46 -0700 Message-ID: <4D386820.5080902@austin.ibm.com> Date: Thu, 20 Jan 2011 10:51:44 -0600 From: Nathan Fontenot MIME-Version: 1.0 Subject: Re: [PATCH 0/4] De-couple sysfs memory directories from memory sections References: <4D386498.9080201@austin.ibm.com> <20110120164555.GA30922@kroah.com> In-Reply-To: <20110120164555.GA30922@kroah.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Greg KH Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, KAMEZAWA Hiroyuki , Robin Holt List-ID: On 01/20/2011 10:45 AM, Greg KH wrote: > On Thu, Jan 20, 2011 at 10:36:40AM -0600, Nathan Fontenot wrote: >> The root of this issue is in sysfs directory creation. Every time >> a directory is created a string compare is done against sibling >> directories ( see sysfs_find_dirent() ) to ensure we do not create >> duplicates. The list of directory nodes in sysfs is kept as an >> unsorted list which results in this being an exponentially longer >> operation as the number of directories are created. > > Again, are you sure about this? I thought we resolved this issue in the > past, but you were going to check it. Did you? > Yes, the string compare is still present in the sysfs code. There was discussion around this sometime last year when I sent a patch out that stored the directory entries in something other than a linked list. That patch was rejected but it was agreed that something should be done. -Nathan -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org