204 lines
6.0 KiB
C
204 lines
6.0 KiB
C
/*
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* hangcheck-timer.c
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*
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* Driver for a little io fencing timer.
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*
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* Copyright (C) 2002, 2003 Oracle. All rights reserved.
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*
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* Author: Joel Becker <joel.becker@oracle.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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/*
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* The hangcheck-timer driver uses the TSC to catch delays that
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* jiffies does not notice. A timer is set. When the timer fires, it
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* checks whether it was delayed and if that delay exceeds a given
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* margin of error. The hangcheck_tick module paramter takes the timer
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* duration in seconds. The hangcheck_margin parameter defines the
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* margin of error, in seconds. The defaults are 60 seconds for the
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* timer and 180 seconds for the margin of error. IOW, a timer is set
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* for 60 seconds. When the timer fires, the callback checks the
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* actual duration that the timer waited. If the duration exceeds the
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* alloted time and margin (here 60 + 180, or 240 seconds), the machine
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* is restarted. A healthy machine will have the duration match the
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* expected timeout very closely.
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/reboot.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <asm/uaccess.h>
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#include <linux/sysrq.h>
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#include <linux/timer.h>
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#define VERSION_STR "0.9.0"
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#define DEFAULT_IOFENCE_MARGIN 60 /* Default fudge factor, in seconds */
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#define DEFAULT_IOFENCE_TICK 180 /* Default timer timeout, in seconds */
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static int hangcheck_tick = DEFAULT_IOFENCE_TICK;
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static int hangcheck_margin = DEFAULT_IOFENCE_MARGIN;
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static int hangcheck_reboot; /* Defaults to not reboot */
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static int hangcheck_dump_tasks; /* Defaults to not dumping SysRQ T */
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/* options - modular */
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module_param(hangcheck_tick, int, 0);
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MODULE_PARM_DESC(hangcheck_tick, "Timer delay.");
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module_param(hangcheck_margin, int, 0);
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MODULE_PARM_DESC(hangcheck_margin, "If the hangcheck timer has been delayed more than hangcheck_margin seconds, the driver will fire.");
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module_param(hangcheck_reboot, int, 0);
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MODULE_PARM_DESC(hangcheck_reboot, "If nonzero, the machine will reboot when the timer margin is exceeded.");
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module_param(hangcheck_dump_tasks, int, 0);
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MODULE_PARM_DESC(hangcheck_dump_tasks, "If nonzero, the machine will dump the system task state when the timer margin is exceeded.");
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MODULE_AUTHOR("Oracle");
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MODULE_DESCRIPTION("Hangcheck-timer detects when the system has gone out to lunch past a certain margin.");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(VERSION_STR);
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/* options - nonmodular */
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#ifndef MODULE
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static int __init hangcheck_parse_tick(char *str)
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{
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int par;
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if (get_option(&str,&par))
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hangcheck_tick = par;
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return 1;
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}
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static int __init hangcheck_parse_margin(char *str)
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{
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int par;
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if (get_option(&str,&par))
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hangcheck_margin = par;
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return 1;
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}
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static int __init hangcheck_parse_reboot(char *str)
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{
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int par;
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if (get_option(&str,&par))
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hangcheck_reboot = par;
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return 1;
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}
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static int __init hangcheck_parse_dump_tasks(char *str)
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{
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int par;
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if (get_option(&str,&par))
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hangcheck_dump_tasks = par;
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return 1;
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}
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__setup("hcheck_tick", hangcheck_parse_tick);
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__setup("hcheck_margin", hangcheck_parse_margin);
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__setup("hcheck_reboot", hangcheck_parse_reboot);
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__setup("hcheck_dump_tasks", hangcheck_parse_dump_tasks);
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#endif /* not MODULE */
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#if defined(CONFIG_S390)
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# define HAVE_MONOTONIC
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# define TIMER_FREQ 1000000000ULL
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#elif defined(CONFIG_IA64)
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# define TIMER_FREQ ((unsigned long long)local_cpu_data->itc_freq)
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#else
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# define TIMER_FREQ (HZ*loops_per_jiffy)
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#endif
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#ifdef HAVE_MONOTONIC
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extern unsigned long long monotonic_clock(void);
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#else
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static inline unsigned long long monotonic_clock(void)
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{
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return get_cycles();
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}
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#endif /* HAVE_MONOTONIC */
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/* Last time scheduled */
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static unsigned long long hangcheck_tsc, hangcheck_tsc_margin;
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static void hangcheck_fire(unsigned long);
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static DEFINE_TIMER(hangcheck_ticktock, hangcheck_fire, 0, 0);
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static void hangcheck_fire(unsigned long data)
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{
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unsigned long long cur_tsc, tsc_diff;
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cur_tsc = monotonic_clock();
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if (cur_tsc > hangcheck_tsc)
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tsc_diff = cur_tsc - hangcheck_tsc;
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else
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tsc_diff = (cur_tsc + (~0ULL - hangcheck_tsc)); /* or something */
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if (tsc_diff > hangcheck_tsc_margin) {
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if (hangcheck_dump_tasks) {
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printk(KERN_CRIT "Hangcheck: Task state:\n");
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#ifdef CONFIG_MAGIC_SYSRQ
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handle_sysrq('t', NULL);
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#endif /* CONFIG_MAGIC_SYSRQ */
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}
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if (hangcheck_reboot) {
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printk(KERN_CRIT "Hangcheck: hangcheck is restarting the machine.\n");
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emergency_restart();
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} else {
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printk(KERN_CRIT "Hangcheck: hangcheck value past margin!\n");
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}
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}
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mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
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hangcheck_tsc = monotonic_clock();
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}
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static int __init hangcheck_init(void)
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{
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printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
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VERSION_STR, hangcheck_tick, hangcheck_margin);
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#if defined (HAVE_MONOTONIC)
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printk("Hangcheck: Using monotonic_clock().\n");
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#else
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printk("Hangcheck: Using get_cycles().\n");
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#endif /* HAVE_MONOTONIC */
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hangcheck_tsc_margin =
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(unsigned long long)(hangcheck_margin + hangcheck_tick);
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hangcheck_tsc_margin *= (unsigned long long)TIMER_FREQ;
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hangcheck_tsc = monotonic_clock();
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mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
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return 0;
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}
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static void __exit hangcheck_exit(void)
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{
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del_timer_sync(&hangcheck_ticktock);
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printk("Hangcheck: Stopped hangcheck timer.\n");
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}
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module_init(hangcheck_init);
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module_exit(hangcheck_exit);
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