Root/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#define RCU_TREE_NONCORE
47#include "rcutree.h"
48
49static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
50{
51    if (!rdp->beenonline)
52        return;
53    seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pqc=%lu qp=%d",
54           rdp->cpu,
55           cpu_is_offline(rdp->cpu) ? '!' : ' ',
56           rdp->completed, rdp->gpnum,
57           rdp->passed_quiesc, rdp->passed_quiesc_completed,
58           rdp->qs_pending);
59#ifdef CONFIG_NO_HZ
60    seq_printf(m, " dt=%d/%d dn=%d df=%lu",
61           rdp->dynticks->dynticks,
62           rdp->dynticks->dynticks_nesting,
63           rdp->dynticks->dynticks_nmi,
64           rdp->dynticks_fqs);
65#endif /* #ifdef CONFIG_NO_HZ */
66    seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);
67    seq_printf(m, " ql=%ld b=%ld\n", rdp->qlen, rdp->blimit);
68}
69
70#define PRINT_RCU_DATA(name, func, m) \
71    do { \
72        int _p_r_d_i; \
73        \
74        for_each_possible_cpu(_p_r_d_i) \
75            func(m, &per_cpu(name, _p_r_d_i)); \
76    } while (0)
77
78static int show_rcudata(struct seq_file *m, void *unused)
79{
80#ifdef CONFIG_TREE_PREEMPT_RCU
81    seq_puts(m, "rcu_preempt:\n");
82    PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data, m);
83#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
84    seq_puts(m, "rcu_sched:\n");
85    PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data, m);
86    seq_puts(m, "rcu_bh:\n");
87    PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
88    return 0;
89}
90
91static int rcudata_open(struct inode *inode, struct file *file)
92{
93    return single_open(file, show_rcudata, NULL);
94}
95
96static const struct file_operations rcudata_fops = {
97    .owner = THIS_MODULE,
98    .open = rcudata_open,
99    .read = seq_read,
100    .llseek = seq_lseek,
101    .release = single_release,
102};
103
104static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
105{
106    if (!rdp->beenonline)
107        return;
108    seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
109           rdp->cpu,
110           cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
111           rdp->completed, rdp->gpnum,
112           rdp->passed_quiesc, rdp->passed_quiesc_completed,
113           rdp->qs_pending);
114#ifdef CONFIG_NO_HZ
115    seq_printf(m, ",%d,%d,%d,%lu",
116           rdp->dynticks->dynticks,
117           rdp->dynticks->dynticks_nesting,
118           rdp->dynticks->dynticks_nmi,
119           rdp->dynticks_fqs);
120#endif /* #ifdef CONFIG_NO_HZ */
121    seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
122    seq_printf(m, ",%ld,%ld\n", rdp->qlen, rdp->blimit);
123}
124
125static int show_rcudata_csv(struct seq_file *m, void *unused)
126{
127    seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
128#ifdef CONFIG_NO_HZ
129    seq_puts(m, "\"dt\",\"dt nesting\",\"dn\",\"df\",");
130#endif /* #ifdef CONFIG_NO_HZ */
131    seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\"\n");
132#ifdef CONFIG_TREE_PREEMPT_RCU
133    seq_puts(m, "\"rcu_preempt:\"\n");
134    PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data_csv, m);
135#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
136    seq_puts(m, "\"rcu_sched:\"\n");
137    PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data_csv, m);
138    seq_puts(m, "\"rcu_bh:\"\n");
139    PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
140    return 0;
141}
142
143static int rcudata_csv_open(struct inode *inode, struct file *file)
144{
145    return single_open(file, show_rcudata_csv, NULL);
146}
147
148static const struct file_operations rcudata_csv_fops = {
149    .owner = THIS_MODULE,
150    .open = rcudata_csv_open,
151    .read = seq_read,
152    .llseek = seq_lseek,
153    .release = single_release,
154};
155
156static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
157{
158    unsigned long gpnum;
159    int level = 0;
160    int phase;
161    struct rcu_node *rnp;
162
163    gpnum = rsp->gpnum;
164    seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "
165              "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld\n",
166           rsp->completed, gpnum, rsp->signaled,
167           (long)(rsp->jiffies_force_qs - jiffies),
168           (int)(jiffies & 0xffff),
169           rsp->n_force_qs, rsp->n_force_qs_ngp,
170           rsp->n_force_qs - rsp->n_force_qs_ngp,
171           rsp->n_force_qs_lh, rsp->orphan_qlen);
172    for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
173        if (rnp->level != level) {
174            seq_puts(m, "\n");
175            level = rnp->level;
176        }
177        phase = gpnum & 0x1;
178        seq_printf(m, "%lx/%lx %c%c>%c%c %d:%d ^%d ",
179               rnp->qsmask, rnp->qsmaskinit,
180               "T."[list_empty(&rnp->blocked_tasks[phase])],
181               "E."[list_empty(&rnp->blocked_tasks[phase + 2])],
182               "T."[list_empty(&rnp->blocked_tasks[!phase])],
183               "E."[list_empty(&rnp->blocked_tasks[!phase + 2])],
184               rnp->grplo, rnp->grphi, rnp->grpnum);
185    }
186    seq_puts(m, "\n");
187}
188
189static int show_rcuhier(struct seq_file *m, void *unused)
190{
191#ifdef CONFIG_TREE_PREEMPT_RCU
192    seq_puts(m, "rcu_preempt:\n");
193    print_one_rcu_state(m, &rcu_preempt_state);
194#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
195    seq_puts(m, "rcu_sched:\n");
196    print_one_rcu_state(m, &rcu_sched_state);
197    seq_puts(m, "rcu_bh:\n");
198    print_one_rcu_state(m, &rcu_bh_state);
199    return 0;
200}
201
202static int rcuhier_open(struct inode *inode, struct file *file)
203{
204    return single_open(file, show_rcuhier, NULL);
205}
206
207static const struct file_operations rcuhier_fops = {
208    .owner = THIS_MODULE,
209    .open = rcuhier_open,
210    .read = seq_read,
211    .llseek = seq_lseek,
212    .release = single_release,
213};
214
215static int show_rcugp(struct seq_file *m, void *unused)
216{
217#ifdef CONFIG_TREE_PREEMPT_RCU
218    seq_printf(m, "rcu_preempt: completed=%ld gpnum=%lu\n",
219           rcu_preempt_state.completed, rcu_preempt_state.gpnum);
220#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
221    seq_printf(m, "rcu_sched: completed=%ld gpnum=%lu\n",
222           rcu_sched_state.completed, rcu_sched_state.gpnum);
223    seq_printf(m, "rcu_bh: completed=%ld gpnum=%lu\n",
224           rcu_bh_state.completed, rcu_bh_state.gpnum);
225    return 0;
226}
227
228static int rcugp_open(struct inode *inode, struct file *file)
229{
230    return single_open(file, show_rcugp, NULL);
231}
232
233static const struct file_operations rcugp_fops = {
234    .owner = THIS_MODULE,
235    .open = rcugp_open,
236    .read = seq_read,
237    .llseek = seq_lseek,
238    .release = single_release,
239};
240
241static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
242{
243    seq_printf(m, "%3d%cnp=%ld "
244           "qsp=%ld rpq=%ld cbr=%ld cng=%ld "
245           "gpc=%ld gps=%ld nf=%ld nn=%ld\n",
246           rdp->cpu,
247           cpu_is_offline(rdp->cpu) ? '!' : ' ',
248           rdp->n_rcu_pending,
249           rdp->n_rp_qs_pending,
250           rdp->n_rp_report_qs,
251           rdp->n_rp_cb_ready,
252           rdp->n_rp_cpu_needs_gp,
253           rdp->n_rp_gp_completed,
254           rdp->n_rp_gp_started,
255           rdp->n_rp_need_fqs,
256           rdp->n_rp_need_nothing);
257}
258
259static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
260{
261    int cpu;
262    struct rcu_data *rdp;
263
264    for_each_possible_cpu(cpu) {
265        rdp = rsp->rda[cpu];
266        if (rdp->beenonline)
267            print_one_rcu_pending(m, rdp);
268    }
269}
270
271static int show_rcu_pending(struct seq_file *m, void *unused)
272{
273#ifdef CONFIG_TREE_PREEMPT_RCU
274    seq_puts(m, "rcu_preempt:\n");
275    print_rcu_pendings(m, &rcu_preempt_state);
276#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
277    seq_puts(m, "rcu_sched:\n");
278    print_rcu_pendings(m, &rcu_sched_state);
279    seq_puts(m, "rcu_bh:\n");
280    print_rcu_pendings(m, &rcu_bh_state);
281    return 0;
282}
283
284static int rcu_pending_open(struct inode *inode, struct file *file)
285{
286    return single_open(file, show_rcu_pending, NULL);
287}
288
289static const struct file_operations rcu_pending_fops = {
290    .owner = THIS_MODULE,
291    .open = rcu_pending_open,
292    .read = seq_read,
293    .llseek = seq_lseek,
294    .release = single_release,
295};
296
297static struct dentry *rcudir;
298
299static int __init rcuclassic_trace_init(void)
300{
301    struct dentry *retval;
302
303    rcudir = debugfs_create_dir("rcu", NULL);
304    if (!rcudir)
305        goto free_out;
306
307    retval = debugfs_create_file("rcudata", 0444, rcudir,
308                        NULL, &rcudata_fops);
309    if (!retval)
310        goto free_out;
311
312    retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
313                        NULL, &rcudata_csv_fops);
314    if (!retval)
315        goto free_out;
316
317    retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
318    if (!retval)
319        goto free_out;
320
321    retval = debugfs_create_file("rcuhier", 0444, rcudir,
322                        NULL, &rcuhier_fops);
323    if (!retval)
324        goto free_out;
325
326    retval = debugfs_create_file("rcu_pending", 0444, rcudir,
327                        NULL, &rcu_pending_fops);
328    if (!retval)
329        goto free_out;
330    return 0;
331free_out:
332    debugfs_remove_recursive(rcudir);
333    return 1;
334}
335
336static void __exit rcuclassic_trace_cleanup(void)
337{
338    debugfs_remove_recursive(rcudir);
339}
340
341
342module_init(rcuclassic_trace_init);
343module_exit(rcuclassic_trace_cleanup);
344
345MODULE_AUTHOR("Paul E. McKenney");
346MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
347MODULE_LICENSE("GPL");
348

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