Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/drivers/char/hangcheck-timer.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 6615 byte(s)
Tag kernel26-2.6.12-alx-r9
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 paramter 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/smp_lock.h> |
48 | #include <linux/init.h> |
49 | #include <linux/delay.h> |
50 | #include <asm/uaccess.h> |
51 | #include <linux/sysrq.h> |
52 | |
53 | |
54 | #define VERSION_STR "0.9.0" |
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_X86) || defined(CONFIG_X86_64) |
121 | # define HAVE_MONOTONIC |
122 | # define TIMER_FREQ 1000000000ULL |
123 | #elif defined(CONFIG_ARCH_S390) |
124 | /* FA240000 is 1 Second in the IBM time universe (Page 4-38 Principles of Op for zSeries */ |
125 | # define TIMER_FREQ 0xFA240000ULL |
126 | #elif defined(CONFIG_IA64) |
127 | # define TIMER_FREQ ((unsigned long long)local_cpu_data->itc_freq) |
128 | #elif defined(CONFIG_PPC64) |
129 | # define TIMER_FREQ (HZ*loops_per_jiffy) |
130 | #endif |
131 | |
132 | #ifdef HAVE_MONOTONIC |
133 | extern unsigned long long monotonic_clock(void); |
134 | #else |
135 | static inline unsigned long long monotonic_clock(void) |
136 | { |
137 | # ifdef __s390__ |
138 | /* returns the TOD. see 4-38 Principles of Op of zSeries */ |
139 | return get_clock(); |
140 | # else |
141 | return get_cycles(); |
142 | # endif /* __s390__ */ |
143 | } |
144 | #endif /* HAVE_MONOTONIC */ |
145 | |
146 | |
147 | /* Last time scheduled */ |
148 | static unsigned long long hangcheck_tsc, hangcheck_tsc_margin; |
149 | |
150 | static void hangcheck_fire(unsigned long); |
151 | |
152 | static struct timer_list hangcheck_ticktock = |
153 | TIMER_INITIALIZER(hangcheck_fire, 0, 0); |
154 | |
155 | |
156 | static void hangcheck_fire(unsigned long data) |
157 | { |
158 | unsigned long long cur_tsc, tsc_diff; |
159 | |
160 | cur_tsc = monotonic_clock(); |
161 | |
162 | if (cur_tsc > hangcheck_tsc) |
163 | tsc_diff = cur_tsc - hangcheck_tsc; |
164 | else |
165 | tsc_diff = (cur_tsc + (~0ULL - hangcheck_tsc)); /* or something */ |
166 | |
167 | if (tsc_diff > hangcheck_tsc_margin) { |
168 | if (hangcheck_dump_tasks) { |
169 | printk(KERN_CRIT "Hangcheck: Task state:\n"); |
170 | #ifdef CONFIG_MAGIC_SYSRQ |
171 | handle_sysrq('t', NULL, NULL); |
172 | #endif /* CONFIG_MAGIC_SYSRQ */ |
173 | } |
174 | if (hangcheck_reboot) { |
175 | printk(KERN_CRIT "Hangcheck: hangcheck is restarting the machine.\n"); |
176 | machine_restart(NULL); |
177 | } else { |
178 | printk(KERN_CRIT "Hangcheck: hangcheck value past margin!\n"); |
179 | } |
180 | } |
181 | mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ)); |
182 | hangcheck_tsc = monotonic_clock(); |
183 | } |
184 | |
185 | |
186 | static int __init hangcheck_init(void) |
187 | { |
188 | printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n", |
189 | VERSION_STR, hangcheck_tick, hangcheck_margin); |
190 | #if defined (HAVE_MONOTONIC) |
191 | printk("Hangcheck: Using monotonic_clock().\n"); |
192 | #elif defined(__s390__) |
193 | printk("Hangcheck: Using TOD.\n"); |
194 | #else |
195 | printk("Hangcheck: Using get_cycles().\n"); |
196 | #endif /* HAVE_MONOTONIC */ |
197 | hangcheck_tsc_margin = |
198 | (unsigned long long)(hangcheck_margin + hangcheck_tick); |
199 | hangcheck_tsc_margin *= (unsigned long long)TIMER_FREQ; |
200 | |
201 | hangcheck_tsc = monotonic_clock(); |
202 | mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ)); |
203 | |
204 | return 0; |
205 | } |
206 | |
207 | |
208 | static void __exit hangcheck_exit(void) |
209 | { |
210 | del_timer_sync(&hangcheck_ticktock); |
211 | printk("Hangcheck: Stopped hangcheck timer.\n"); |
212 | } |
213 | |
214 | module_init(hangcheck_init); |
215 | module_exit(hangcheck_exit); |