Root/
1 | /* |
2 | * hangcheck-timer.c |
3 | * |
4 | * Driver for a little io fencing timer. |
5 | * |
6 | * Copyright (C) 2002, 2003 Oracle. All rights reserved. |
7 | * |
8 | * Author: Joel Becker <joel.becker@oracle.com> |
9 | * |
10 | * This program is free software; you can redistribute it and/or |
11 | * modify it under the terms of the GNU General Public |
12 | * License version 2 as published by the Free Software Foundation. |
13 | * |
14 | * This program is distributed in the hope that it will be useful, |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
17 | * General Public License for more details. |
18 | * |
19 | * You should have received a copy of the GNU General Public |
20 | * License along with this program; if not, write to the |
21 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
22 | * Boston, MA 021110-1307, USA. |
23 | */ |
24 | |
25 | /* |
26 | * The hangcheck-timer driver uses the TSC to catch delays that |
27 | * jiffies does not notice. A timer is set. When the timer fires, it |
28 | * checks whether it was delayed and if that delay exceeds a given |
29 | * margin of error. The hangcheck_tick module parameter takes the timer |
30 | * duration in seconds. The hangcheck_margin parameter defines the |
31 | * margin of error, in seconds. The defaults are 60 seconds for the |
32 | * timer and 180 seconds for the margin of error. IOW, a timer is set |
33 | * for 60 seconds. When the timer fires, the callback checks the |
34 | * actual duration that the timer waited. If the duration exceeds the |
35 | * alloted time and margin (here 60 + 180, or 240 seconds), the machine |
36 | * is restarted. A healthy machine will have the duration match the |
37 | * expected timeout very closely. |
38 | */ |
39 | |
40 | #include <linux/module.h> |
41 | #include <linux/moduleparam.h> |
42 | #include <linux/types.h> |
43 | #include <linux/kernel.h> |
44 | #include <linux/fs.h> |
45 | #include <linux/mm.h> |
46 | #include <linux/reboot.h> |
47 | #include <linux/init.h> |
48 | #include <linux/delay.h> |
49 | #include <asm/uaccess.h> |
50 | #include <linux/sysrq.h> |
51 | #include <linux/timer.h> |
52 | #include <linux/time.h> |
53 | |
54 | #define VERSION_STR "0.9.1" |
55 | |
56 | #define DEFAULT_IOFENCE_MARGIN 60 /* Default fudge factor, in seconds */ |
57 | #define DEFAULT_IOFENCE_TICK 180 /* Default timer timeout, in seconds */ |
58 | |
59 | static int hangcheck_tick = DEFAULT_IOFENCE_TICK; |
60 | static int hangcheck_margin = DEFAULT_IOFENCE_MARGIN; |
61 | static int hangcheck_reboot; /* Defaults to not reboot */ |
62 | static int hangcheck_dump_tasks; /* Defaults to not dumping SysRQ T */ |
63 | |
64 | /* options - modular */ |
65 | module_param(hangcheck_tick, int, 0); |
66 | MODULE_PARM_DESC(hangcheck_tick, "Timer delay."); |
67 | module_param(hangcheck_margin, int, 0); |
68 | MODULE_PARM_DESC(hangcheck_margin, "If the hangcheck timer has been delayed more than hangcheck_margin seconds, the driver will fire."); |
69 | module_param(hangcheck_reboot, int, 0); |
70 | MODULE_PARM_DESC(hangcheck_reboot, "If nonzero, the machine will reboot when the timer margin is exceeded."); |
71 | module_param(hangcheck_dump_tasks, int, 0); |
72 | MODULE_PARM_DESC(hangcheck_dump_tasks, "If nonzero, the machine will dump the system task state when the timer margin is exceeded."); |
73 | |
74 | MODULE_AUTHOR("Oracle"); |
75 | MODULE_DESCRIPTION("Hangcheck-timer detects when the system has gone out to lunch past a certain margin."); |
76 | MODULE_LICENSE("GPL"); |
77 | MODULE_VERSION(VERSION_STR); |
78 | |
79 | /* options - nonmodular */ |
80 | #ifndef MODULE |
81 | |
82 | static int __init hangcheck_parse_tick(char *str) |
83 | { |
84 | int par; |
85 | if (get_option(&str,&par)) |
86 | hangcheck_tick = par; |
87 | return 1; |
88 | } |
89 | |
90 | static int __init hangcheck_parse_margin(char *str) |
91 | { |
92 | int par; |
93 | if (get_option(&str,&par)) |
94 | hangcheck_margin = par; |
95 | return 1; |
96 | } |
97 | |
98 | static int __init hangcheck_parse_reboot(char *str) |
99 | { |
100 | int par; |
101 | if (get_option(&str,&par)) |
102 | hangcheck_reboot = par; |
103 | return 1; |
104 | } |
105 | |
106 | static int __init hangcheck_parse_dump_tasks(char *str) |
107 | { |
108 | int par; |
109 | if (get_option(&str,&par)) |
110 | hangcheck_dump_tasks = par; |
111 | return 1; |
112 | } |
113 | |
114 | __setup("hcheck_tick", hangcheck_parse_tick); |
115 | __setup("hcheck_margin", hangcheck_parse_margin); |
116 | __setup("hcheck_reboot", hangcheck_parse_reboot); |
117 | __setup("hcheck_dump_tasks", hangcheck_parse_dump_tasks); |
118 | #endif /* not MODULE */ |
119 | |
120 | #if defined(CONFIG_S390) |
121 | # define HAVE_MONOTONIC |
122 | # define TIMER_FREQ 1000000000ULL |
123 | #else |
124 | # define TIMER_FREQ 1000000000ULL |
125 | #endif |
126 | |
127 | #ifdef HAVE_MONOTONIC |
128 | extern unsigned long long monotonic_clock(void); |
129 | #else |
130 | static inline unsigned long long monotonic_clock(void) |
131 | { |
132 | struct timespec ts; |
133 | getrawmonotonic(&ts); |
134 | return timespec_to_ns(&ts); |
135 | } |
136 | #endif /* HAVE_MONOTONIC */ |
137 | |
138 | |
139 | /* Last time scheduled */ |
140 | static unsigned long long hangcheck_tsc, hangcheck_tsc_margin; |
141 | |
142 | static void hangcheck_fire(unsigned long); |
143 | |
144 | static DEFINE_TIMER(hangcheck_ticktock, hangcheck_fire, 0, 0); |
145 | |
146 | |
147 | static void hangcheck_fire(unsigned long data) |
148 | { |
149 | unsigned long long cur_tsc, tsc_diff; |
150 | |
151 | cur_tsc = monotonic_clock(); |
152 | |
153 | if (cur_tsc > hangcheck_tsc) |
154 | tsc_diff = cur_tsc - hangcheck_tsc; |
155 | else |
156 | tsc_diff = (cur_tsc + (~0ULL - hangcheck_tsc)); /* or something */ |
157 | |
158 | if (tsc_diff > hangcheck_tsc_margin) { |
159 | if (hangcheck_dump_tasks) { |
160 | printk(KERN_CRIT "Hangcheck: Task state:\n"); |
161 | #ifdef CONFIG_MAGIC_SYSRQ |
162 | handle_sysrq('t'); |
163 | #endif /* CONFIG_MAGIC_SYSRQ */ |
164 | } |
165 | if (hangcheck_reboot) { |
166 | printk(KERN_CRIT "Hangcheck: hangcheck is restarting the machine.\n"); |
167 | emergency_restart(); |
168 | } else { |
169 | printk(KERN_CRIT "Hangcheck: hangcheck value past margin!\n"); |
170 | } |
171 | } |
172 | #if 0 |
173 | /* |
174 | * Enable to investigate delays in detail |
175 | */ |
176 | printk("Hangcheck: called %Ld ns since last time (%Ld ns overshoot)\n", |
177 | tsc_diff, tsc_diff - hangcheck_tick*TIMER_FREQ); |
178 | #endif |
179 | mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ)); |
180 | hangcheck_tsc = monotonic_clock(); |
181 | } |
182 | |
183 | |
184 | static int __init hangcheck_init(void) |
185 | { |
186 | printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n", |
187 | VERSION_STR, hangcheck_tick, hangcheck_margin); |
188 | #if defined (HAVE_MONOTONIC) |
189 | printk("Hangcheck: Using monotonic_clock().\n"); |
190 | #else |
191 | printk("Hangcheck: Using getrawmonotonic().\n"); |
192 | #endif /* HAVE_MONOTONIC */ |
193 | hangcheck_tsc_margin = |
194 | (unsigned long long)(hangcheck_margin + hangcheck_tick); |
195 | hangcheck_tsc_margin *= (unsigned long long)TIMER_FREQ; |
196 | |
197 | hangcheck_tsc = monotonic_clock(); |
198 | mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ)); |
199 | |
200 | return 0; |
201 | } |
202 | |
203 | |
204 | static void __exit hangcheck_exit(void) |
205 | { |
206 | del_timer_sync(&hangcheck_ticktock); |
207 | printk("Hangcheck: Stopped hangcheck timer.\n"); |
208 | } |
209 | |
210 | module_init(hangcheck_init); |
211 | module_exit(hangcheck_exit); |
212 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9