From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933264AbXDFWjA (ORCPT ); Fri, 6 Apr 2007 18:39:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933275AbXDFWi7 (ORCPT ); Fri, 6 Apr 2007 18:38:59 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:38103 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933267AbXDFWi6 (ORCPT ); Fri, 6 Apr 2007 18:38:58 -0400 Message-ID: <4616CBF0.7090606@garzik.org> Date: Fri, 06 Apr 2007 18:38:40 -0400 From: Jeff Garzik User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Robin Holt CC: "Eric W. Biederman" , Ingo Molnar , Linus Torvalds , linux-kernel@vger.kernel.org, Jack Steiner Subject: Re: init's children list is long and slows reaping children. References: <20070405195118.GH22762@lnx-holt.americas.sgi.com> In-Reply-To: <20070405195118.GH22762@lnx-holt.americas.sgi.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.3 (----) X-Spam-Report: SpamAssassin version 3.1.8 on srv5.dvmed.net summary: Content analysis details: (-4.3 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Robin Holt wrote: > We have been testing a new larger configuration and we are seeing a very > large scan time of init's tsk->children list. In the cases we are seeing, > there are numerous kernel processes created for each cpu (ie: events/0 > ... events/, xfslogd/0 ... xfslogd/). These are > all on the list ahead of the processes we are currently trying to reap. What about attacking the explosion of kernel threads? As CPU counts increase, the number of per-CPU kernel threads gets really ridiculous. I would rather change the implementation under the hood to start per-CPU threads on demand, similar to a thread-pool implementation. Boxes with $BigNum CPUs probably won't ever use half of those threads. Jeff