KVM: Timer event should not unconditionally unhalt vcpu.
[linux-2.6.git] / kernel / rcutree_trace.c
1 /*
2  * Read-Copy Update tracing for classic implementation
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17  *
18  * Copyright IBM Corporation, 2008
19  *
20  * Papers:  http://www.rdrop.com/users/paulmck/RCU
21  *
22  * For detailed explanation of Read-Copy Update mechanism see -
23  *              Documentation/RCU
24  *
25  */
26 #include <linux/types.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/spinlock.h>
30 #include <linux/smp.h>
31 #include <linux/rcupdate.h>
32 #include <linux/interrupt.h>
33 #include <linux/sched.h>
34 #include <asm/atomic.h>
35 #include <linux/bitops.h>
36 #include <linux/module.h>
37 #include <linux/completion.h>
38 #include <linux/moduleparam.h>
39 #include <linux/percpu.h>
40 #include <linux/notifier.h>
41 #include <linux/cpu.h>
42 #include <linux/mutex.h>
43 #include <linux/debugfs.h>
44 #include <linux/seq_file.h>
45
46 #include "rcutree.h"
47
48 static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
49 {
50         if (!rdp->beenonline)
51                 return;
52         seq_printf(m, "%3d%cc=%ld g=%ld pq=%d pqc=%ld qp=%d",
53                    rdp->cpu,
54                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
55                    rdp->completed, rdp->gpnum,
56                    rdp->passed_quiesc, rdp->passed_quiesc_completed,
57                    rdp->qs_pending);
58 #ifdef CONFIG_NO_HZ
59         seq_printf(m, " dt=%d/%d dn=%d df=%lu",
60                    rdp->dynticks->dynticks,
61                    rdp->dynticks->dynticks_nesting,
62                    rdp->dynticks->dynticks_nmi,
63                    rdp->dynticks_fqs);
64 #endif /* #ifdef CONFIG_NO_HZ */
65         seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);
66         seq_printf(m, " ql=%ld b=%ld\n", rdp->qlen, rdp->blimit);
67 }
68
69 #define PRINT_RCU_DATA(name, func, m) \
70         do { \
71                 int _p_r_d_i; \
72                 \
73                 for_each_possible_cpu(_p_r_d_i) \
74                         func(m, &per_cpu(name, _p_r_d_i)); \
75         } while (0)
76
77 static int show_rcudata(struct seq_file *m, void *unused)
78 {
79         seq_puts(m, "rcu:\n");
80         PRINT_RCU_DATA(rcu_data, print_one_rcu_data, m);
81         seq_puts(m, "rcu_bh:\n");
82         PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
83         return 0;
84 }
85
86 static int rcudata_open(struct inode *inode, struct file *file)
87 {
88         return single_open(file, show_rcudata, NULL);
89 }
90
91 static struct file_operations rcudata_fops = {
92         .owner = THIS_MODULE,
93         .open = rcudata_open,
94         .read = seq_read,
95         .llseek = seq_lseek,
96         .release = single_release,
97 };
98
99 static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
100 {
101         if (!rdp->beenonline)
102                 return;
103         seq_printf(m, "%d,%s,%ld,%ld,%d,%ld,%d",
104                    rdp->cpu,
105                    cpu_is_offline(rdp->cpu) ? "\"Y\"" : "\"N\"",
106                    rdp->completed, rdp->gpnum,
107                    rdp->passed_quiesc, rdp->passed_quiesc_completed,
108                    rdp->qs_pending);
109 #ifdef CONFIG_NO_HZ
110         seq_printf(m, ",%d,%d,%d,%lu",
111                    rdp->dynticks->dynticks,
112                    rdp->dynticks->dynticks_nesting,
113                    rdp->dynticks->dynticks_nmi,
114                    rdp->dynticks_fqs);
115 #endif /* #ifdef CONFIG_NO_HZ */
116         seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
117         seq_printf(m, ",%ld,%ld\n", rdp->qlen, rdp->blimit);
118 }
119
120 static int show_rcudata_csv(struct seq_file *m, void *unused)
121 {
122         seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
123 #ifdef CONFIG_NO_HZ
124         seq_puts(m, "\"dt\",\"dt nesting\",\"dn\",\"df\",");
125 #endif /* #ifdef CONFIG_NO_HZ */
126         seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\"\n");
127         seq_puts(m, "\"rcu:\"\n");
128         PRINT_RCU_DATA(rcu_data, print_one_rcu_data_csv, m);
129         seq_puts(m, "\"rcu_bh:\"\n");
130         PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
131         return 0;
132 }
133
134 static int rcudata_csv_open(struct inode *inode, struct file *file)
135 {
136         return single_open(file, show_rcudata_csv, NULL);
137 }
138
139 static struct file_operations rcudata_csv_fops = {
140         .owner = THIS_MODULE,
141         .open = rcudata_csv_open,
142         .read = seq_read,
143         .llseek = seq_lseek,
144         .release = single_release,
145 };
146
147 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
148 {
149         int level = 0;
150         struct rcu_node *rnp;
151
152         seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x "
153                       "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
154                    rsp->completed, rsp->gpnum, rsp->signaled,
155                    (long)(rsp->jiffies_force_qs - jiffies),
156                    (int)(jiffies & 0xffff),
157                    rsp->n_force_qs, rsp->n_force_qs_ngp,
158                    rsp->n_force_qs - rsp->n_force_qs_ngp,
159                    rsp->n_force_qs_lh);
160         for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
161                 if (rnp->level != level) {
162                         seq_puts(m, "\n");
163                         level = rnp->level;
164                 }
165                 seq_printf(m, "%lx/%lx %d:%d ^%d    ",
166                            rnp->qsmask, rnp->qsmaskinit,
167                            rnp->grplo, rnp->grphi, rnp->grpnum);
168         }
169         seq_puts(m, "\n");
170 }
171
172 static int show_rcuhier(struct seq_file *m, void *unused)
173 {
174         seq_puts(m, "rcu:\n");
175         print_one_rcu_state(m, &rcu_state);
176         seq_puts(m, "rcu_bh:\n");
177         print_one_rcu_state(m, &rcu_bh_state);
178         return 0;
179 }
180
181 static int rcuhier_open(struct inode *inode, struct file *file)
182 {
183         return single_open(file, show_rcuhier, NULL);
184 }
185
186 static struct file_operations rcuhier_fops = {
187         .owner = THIS_MODULE,
188         .open = rcuhier_open,
189         .read = seq_read,
190         .llseek = seq_lseek,
191         .release = single_release,
192 };
193
194 static int show_rcugp(struct seq_file *m, void *unused)
195 {
196         seq_printf(m, "rcu: completed=%ld  gpnum=%ld\n",
197                    rcu_state.completed, rcu_state.gpnum);
198         seq_printf(m, "rcu_bh: completed=%ld  gpnum=%ld\n",
199                    rcu_bh_state.completed, rcu_bh_state.gpnum);
200         return 0;
201 }
202
203 static int rcugp_open(struct inode *inode, struct file *file)
204 {
205         return single_open(file, show_rcugp, NULL);
206 }
207
208 static struct file_operations rcugp_fops = {
209         .owner = THIS_MODULE,
210         .open = rcugp_open,
211         .read = seq_read,
212         .llseek = seq_lseek,
213         .release = single_release,
214 };
215
216 static struct dentry *rcudir, *datadir, *datadir_csv, *hierdir, *gpdir;
217 static int __init rcuclassic_trace_init(void)
218 {
219         rcudir = debugfs_create_dir("rcu", NULL);
220         if (!rcudir)
221                 goto out;
222
223         datadir = debugfs_create_file("rcudata", 0444, rcudir,
224                                                 NULL, &rcudata_fops);
225         if (!datadir)
226                 goto free_out;
227
228         datadir_csv = debugfs_create_file("rcudata.csv", 0444, rcudir,
229                                                 NULL, &rcudata_csv_fops);
230         if (!datadir_csv)
231                 goto free_out;
232
233         gpdir = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
234         if (!gpdir)
235                 goto free_out;
236
237         hierdir = debugfs_create_file("rcuhier", 0444, rcudir,
238                                                 NULL, &rcuhier_fops);
239         if (!hierdir)
240                 goto free_out;
241         return 0;
242 free_out:
243         if (datadir)
244                 debugfs_remove(datadir);
245         if (datadir_csv)
246                 debugfs_remove(datadir_csv);
247         if (gpdir)
248                 debugfs_remove(gpdir);
249         debugfs_remove(rcudir);
250 out:
251         return 1;
252 }
253
254 static void __exit rcuclassic_trace_cleanup(void)
255 {
256         debugfs_remove(datadir);
257         debugfs_remove(datadir_csv);
258         debugfs_remove(gpdir);
259         debugfs_remove(hierdir);
260         debugfs_remove(rcudir);
261 }
262
263
264 module_init(rcuclassic_trace_init);
265 module_exit(rcuclassic_trace_cleanup);
266
267 MODULE_AUTHOR("Paul E. McKenney");
268 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
269 MODULE_LICENSE("GPL");