Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 21 Jan 2003 13:35:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 21 Jan 2003 13:35:11 -0500 Received: from inet-mail3.oracle.com ([148.87.2.203]:50089 "EHLO inet-mail3.oracle.com") by vger.kernel.org with ESMTP id ; Tue, 21 Jan 2003 13:35:07 -0500 Date: Tue, 21 Jan 2003 10:44:04 -0800 From: Joel Becker To: Christoph Hellwig Cc: lkml , Andrew Morton , Linus Torvalds , Wim Coekaerts Subject: Re: [PATCH (take 2)][2.5] hangcheck-timer Message-ID: <20030121184403.GY20972@ca-server1.us.oracle.com> References: <20030121011954.GO20972@ca-server1.us.oracle.com> <20030121081158.A21080@infradead.org> <20030121173303.GU20972@ca-server1.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030121173303.GU20972@ca-server1.us.oracle.com> User-Agent: Mutt/1.4i X-Burt-Line: Trees are cool. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Updated with suggested fixes. Joel diff -uNr linux-2.5.59/drivers/char/Kconfig linux-2.5.59-hangcheck/drivers/char/Kconfig --- linux-2.5.59/drivers/char/Kconfig Thu Jan 16 18:21:36 2003 +++ linux-2.5.59-hangcheck/drivers/char/Kconfig Mon Jan 20 13:35:27 2003 @@ -992,5 +992,8 @@ Once bound, I/O against /dev/raw/rawN uses efficient zero-copy I/O. See the raw(8) manpage for more details. +config HANGCHECK_TIMER + tristate "Hangcheck timer" + endmenu diff -uNr linux-2.5.59/drivers/char/Makefile linux-2.5.59-hangcheck/drivers/char/Makefile --- linux-2.5.59/drivers/char/Makefile Thu Jan 16 18:22:44 2003 +++ linux-2.5.59-hangcheck/drivers/char/Makefile Mon Jan 20 13:35:02 2003 @@ -84,6 +84,7 @@ obj-$(CONFIG_PCMCIA) += pcmcia/ obj-$(CONFIG_IPMI_HANDLER) += ipmi/ +obj-$(CONFIG_HANGCHECK_TIMER) += hangcheck-timer.o # Files generated that shall be removed upon make clean clean-files := consolemap_deftbl.c defkeymap.c qtronixmap.c diff -uNr linux-2.5.59/drivers/char/hangcheck-timer.c linux-2.5.59-hangcheck/drivers/char/hangcheck-timer.c --- linux-2.5.59/drivers/char/hangcheck-timer.c Wed Dec 31 16:00:00 1969 +++ linux-2.5.59-hangcheck/drivers/char/hangcheck-timer.c Tue Jan 21 10:36:01 2003 @@ -0,0 +1,127 @@ +/* + * hangcheck-timer.c + * + * Driver for a little io fencing timer. + * + * Copyright (C) 2002 Oracle Corporation. All rights reserved. + * + * Author: Joel Becker + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have recieved a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +/* + * The hangcheck-timer driver uses the TSC to catch delays that + * jiffies does not notice. A timer is set. When the timer fires, it + * checks whether it was delayed and if that delay exceeds a given + * margin of error. The hangcheck_tick module paramter takes the timer + * duration in seconds. The hangcheck_margin parameter defines the + * margin of error, in seconds. The defaults are 60 seconds for the + * timer and 180 seconds for the margin of error. IOW, a timer is set + * for 60 seconds. When the timer fires, the callback checks the + * actual duration that the timer waited. If the duration exceeds the + * alloted time and margin (here 60 + 180, or 240 seconds), the machine + * is restarted. A healthy machine will have the duration match the + * expected timeout very closely. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + + +#define VERSION_STR "0.5.0" + +#define DEFAULT_IOFENCE_MARGIN 60 /* Default fudge factor, in seconds */ +#define DEFAULT_IOFENCE_TICK 180 /* Default timer timeout, in seconds */ + +static int hangcheck_tick = DEFAULT_IOFENCE_TICK; +static int hangcheck_margin = DEFAULT_IOFENCE_MARGIN; +static int hangcheck_reboot; /* Defaults to not reboot */ + +/* Driver options */ +module_param(hangcheck_tick, int, 0); +MODULE_PARM_DESC(hangcheck_tick, "Timer delay."); +module_param(hangcheck_margin, int, 0); +MODULE_PARM_DESC(hangcheck_margin, "If the hangcheck timer has been delayed more than hangcheck_margin seconds, the driver will fire."); +module_param(hangcheck_reboot, int, 0); +MODULE_PARM_DESC(hangcheck_reboot, "If nonzero, the machine will reboot when the timer margin is exceeded."); + +MODULE_AUTHOR("Joel Becker"); +MODULE_LICENSE("GPL"); + + +/* Last time scheduled */ +static unsigned long long hangcheck_tsc, hangcheck_tsc_margin; + +static void hangcheck_fire(unsigned long); + +static struct timer_list hangcheck_ticktock = { + function: hangcheck_fire, +}; + + +static void hangcheck_fire(unsigned long data) +{ + unsigned long long cur_tsc, tsc_diff; + + cur_tsc = get_cycles(); + + if (cur_tsc > hangcheck_tsc) + tsc_diff = cur_tsc - hangcheck_tsc; + else + tsc_diff = (cur_tsc + (~0ULL - hangcheck_tsc)); /* or something */ + + if (tsc_diff > hangcheck_tsc_margin) { + if (hangcheck_reboot) { + printk(KERN_CRIT "Hangcheck: hangcheck is restarting the machine.\n"); + machine_restart(NULL); + } else { + printk(KERN_CRIT "Hangcheck: hangcheck value past margin!\n"); + } + } + mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ)); + hangcheck_tsc = get_cycles(); +} /* hangcheck_fire() */ + + +static int __init hangcheck_init(void) +{ + printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n", + VERSION_STR, hangcheck_tick, hangcheck_margin); + + hangcheck_tsc_margin = (unsigned long long)(hangcheck_margin + hangcheck_tick) * (unsigned long long)HZ * (unsigned long long)current_cpu_data.loops_per_jiffy; + + hangcheck_tsc = get_cycles(); + mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ)); + + return 0; +} /* hangcheck_init() */ + + +static void __exit hangcheck_exit(void) +{ + del_timer_sync(&hangcheck_ticktock); +} /* hangcheck_exit() */ + +module_init(hangcheck_init); +module_exit(hangcheck_exit); -- "Hell is oneself, hell is alone, the other figures in it, merely projections." - T. S. Eliot Joel Becker Senior Member of Technical Staff Oracle Corporation E-mail: joel.becker@oracle.com Phone: (650) 506-8127 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/