From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761439AbZFJUwV (ORCPT ); Wed, 10 Jun 2009 16:52:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760337AbZFJUwK (ORCPT ); Wed, 10 Jun 2009 16:52:10 -0400 Received: from terminus.zytor.com ([198.137.202.10]:47587 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760162AbZFJUwJ (ORCPT ); Wed, 10 Jun 2009 16:52:09 -0400 Message-ID: <4A301CCD.7070707@zytor.com> Date: Wed, 10 Jun 2009 13:51:25 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Andrew Morton CC: Ray Lee , renton@renton.name, linux-kernel@vger.kernel.org, linux-fsdevel Subject: Re: devpts mounts too slowly References: <20090603142801.GC21646@beaver.vrungel.ru> <4A26EB18.6060907@zytor.com> <20090609161945.811cc01f.akpm@linux-foundation.org> <2c0942db0906091630l1cc79647h8689e9e929ed1bba@mail.gmail.com> <20090609165304.add1a872.akpm@linux-foundation.org> In-Reply-To: <20090609165304.add1a872.akpm@linux-foundation.org> 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 Andrew Morton wrote: > > hm, OK. > > I've now mounted 15000 devpts's and still no slowdown is evident. I ran my test script, mounting ramfs, with n=100000, and well, gave up since it hadn't gotten any further than 57000 or so overnight. At that time each individual mount was taking several seconds. Graphing the delays seem to indicate O(n^2) behavior. umounts do not appear affected; each umount still take negible time. -hpa