From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755486AbYLOQjS (ORCPT ); Mon, 15 Dec 2008 11:39:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753560AbYLOQjH (ORCPT ); Mon, 15 Dec 2008 11:39:07 -0500 Received: from golem.dinale.com ([82.208.35.193]:44016 "EHLO bobrock.dinale.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753548AbYLOQjH (ORCPT ); Mon, 15 Dec 2008 11:39:07 -0500 X-Greylist: delayed 2060 seconds by postgrey-1.27 at vger.kernel.org; Mon, 15 Dec 2008 11:39:06 EST Message-ID: <49468024.1020700@dei.unipd.it> Date: Mon, 15 Dec 2008 17:04:52 +0100 From: Ottavio Campana User-Agent: Thunderbird 2.0.0.18 (Macintosh/20081105) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Oops when trying to create more than 16000 timers Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, I'm sorry if it is not the best place to ask, but I haven't find any answer. I am currently developing a software that needs approx 60k timers. I currently use timer_create and all the relative functions to manage timers. I've noticed that after having created 16039 timers I always get an oops from the kernel, which are always of the same kind: Dec 15 15:20:00 evolution kernel: [601680.417064] BUG: unable to handle kernel NULL pointer dereference at 0000000000000040 . I tried looking at kernel/posix-timers.c and I discovered that posix timers are kept in slab memory. By monitoring the my program I can see that in /proc/slabinfo the number of timers increases till 16039, when I get the oops and no more timers are created. In /prob/slabinfo I have posix_timers_cache 0 0 192 20 1 : tunables 120 60 8 : slabdata 0 0 0 If I try to increase tunables to 2400 120 16 the maximum number of posix timers that I can create does not change. How can I tune the kernel so that it supports 60k or more timers? Thank for your help, Ottavio -- Ottavio Campana Telecommunication Engineer Lab. Immagini Dept. of Information Engineering University of Padova Via Gradenigo 6/B 35131 Padova Italy phone: +39 049 8277641 fax: +39 049 8277699 e-mail: ottavio.campana@dei.unipd.it