rcu: Add boosting to TREE_PREEMPT_RCU tracing
[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 #define RCU_TREE_NONCORE
47 #include "rcutree.h"
48
49 static 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/%d df=%lu",
61                    atomic_read(&rdp->dynticks->dynticks),
62                    rdp->dynticks->dynticks_nesting,
63                    rdp->dynticks->dynticks_nmi_nesting,
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", rdp->qlen, rdp->blimit);
68         seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
69                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
70 }
71
72 #define PRINT_RCU_DATA(name, func, m) \
73         do { \
74                 int _p_r_d_i; \
75                 \
76                 for_each_possible_cpu(_p_r_d_i) \
77                         func(m, &per_cpu(name, _p_r_d_i)); \
78         } while (0)
79
80 static int show_rcudata(struct seq_file *m, void *unused)
81 {
82 #ifdef CONFIG_TREE_PREEMPT_RCU
83         seq_puts(m, "rcu_preempt:\n");
84         PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data, m);
85 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
86         seq_puts(m, "rcu_sched:\n");
87         PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data, m);
88         seq_puts(m, "rcu_bh:\n");
89         PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
90         return 0;
91 }
92
93 static int rcudata_open(struct inode *inode, struct file *file)
94 {
95         return single_open(file, show_rcudata, NULL);
96 }
97
98 static const struct file_operations rcudata_fops = {
99         .owner = THIS_MODULE,
100         .open = rcudata_open,
101         .read = seq_read,
102         .llseek = seq_lseek,
103         .release = single_release,
104 };
105
106 static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
107 {
108         if (!rdp->beenonline)
109                 return;
110         seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
111                    rdp->cpu,
112                    cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
113                    rdp->completed, rdp->gpnum,
114                    rdp->passed_quiesc, rdp->passed_quiesc_completed,
115                    rdp->qs_pending);
116 #ifdef CONFIG_NO_HZ
117         seq_printf(m, ",%d,%d,%d,%lu",
118                    atomic_read(&rdp->dynticks->dynticks),
119                    rdp->dynticks->dynticks_nesting,
120                    rdp->dynticks->dynticks_nmi_nesting,
121                    rdp->dynticks_fqs);
122 #endif /* #ifdef CONFIG_NO_HZ */
123         seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
124         seq_printf(m, ",%ld,%ld", rdp->qlen, rdp->blimit);
125         seq_printf(m, ",%lu,%lu,%lu\n",
126                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
127 }
128
129 static int show_rcudata_csv(struct seq_file *m, void *unused)
130 {
131         seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
132 #ifdef CONFIG_NO_HZ
133         seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");
134 #endif /* #ifdef CONFIG_NO_HZ */
135         seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\",\"ci\",\"co\",\"ca\"\n");
136 #ifdef CONFIG_TREE_PREEMPT_RCU
137         seq_puts(m, "\"rcu_preempt:\"\n");
138         PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data_csv, m);
139 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
140         seq_puts(m, "\"rcu_sched:\"\n");
141         PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data_csv, m);
142         seq_puts(m, "\"rcu_bh:\"\n");
143         PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
144         return 0;
145 }
146
147 static int rcudata_csv_open(struct inode *inode, struct file *file)
148 {
149         return single_open(file, show_rcudata_csv, NULL);
150 }
151
152 static const struct file_operations rcudata_csv_fops = {
153         .owner = THIS_MODULE,
154         .open = rcudata_csv_open,
155         .read = seq_read,
156         .llseek = seq_lseek,
157         .release = single_release,
158 };
159
160 #ifdef CONFIG_RCU_BOOST
161
162 static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
163 {
164         seq_printf(m,  "%d:%d tasks=%c%c%c%c ntb=%lu neb=%lu nnb=%lu "
165                    "j=%04x bt=%04x\n",
166                    rnp->grplo, rnp->grphi,
167                    "T."[list_empty(&rnp->blkd_tasks)],
168                    "N."[!rnp->gp_tasks],
169                    "E."[!rnp->exp_tasks],
170                    "B."[!rnp->boost_tasks],
171                    rnp->n_tasks_boosted, rnp->n_exp_boosts,
172                    rnp->n_normal_boosts,
173                    (int)(jiffies & 0xffff),
174                    (int)(rnp->boost_time & 0xffff));
175         seq_printf(m, "%s: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
176                    "     balk",
177                    rnp->n_balk_blkd_tasks,
178                    rnp->n_balk_exp_gp_tasks,
179                    rnp->n_balk_boost_tasks,
180                    rnp->n_balk_notblocked,
181                    rnp->n_balk_notyet,
182                    rnp->n_balk_nos);
183 }
184
185 static int show_rcu_node_boost(struct seq_file *m, void *unused)
186 {
187         struct rcu_node *rnp;
188
189         rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
190                 print_one_rcu_node_boost(m, rnp);
191         return 0;
192 }
193
194 static int rcu_node_boost_open(struct inode *inode, struct file *file)
195 {
196         return single_open(file, show_rcu_node_boost, NULL);
197 }
198
199 static const struct file_operations rcu_node_boost_fops = {
200         .owner = THIS_MODULE,
201         .open = rcu_node_boost_open,
202         .read = seq_read,
203         .llseek = seq_lseek,
204         .release = single_release,
205 };
206
207 /*
208  * Create the rcuboost debugfs entry.  Standard error return.
209  */
210 static int rcu_boost_trace_create_file(struct dentry *rcudir)
211 {
212         return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
213                                     &rcu_node_boost_fops);
214 }
215
216 #else /* #ifdef CONFIG_RCU_BOOST */
217
218 static int rcu_boost_trace_create_file(struct dentry *rcudir)
219 {
220         return 0;  /* There cannot be an error if we didn't create it! */
221 }
222
223 #endif /* #else #ifdef CONFIG_RCU_BOOST */
224
225 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
226 {
227         unsigned long gpnum;
228         int level = 0;
229         struct rcu_node *rnp;
230
231         gpnum = rsp->gpnum;
232         seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "
233                       "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
234                    rsp->completed, gpnum, rsp->signaled,
235                    (long)(rsp->jiffies_force_qs - jiffies),
236                    (int)(jiffies & 0xffff),
237                    rsp->n_force_qs, rsp->n_force_qs_ngp,
238                    rsp->n_force_qs - rsp->n_force_qs_ngp,
239                    rsp->n_force_qs_lh);
240         for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
241                 if (rnp->level != level) {
242                         seq_puts(m, "\n");
243                         level = rnp->level;
244                 }
245                 seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d    ",
246                            rnp->qsmask, rnp->qsmaskinit,
247                            ".G"[rnp->gp_tasks != NULL],
248                            ".E"[rnp->exp_tasks != NULL],
249                            ".T"[!list_empty(&rnp->blkd_tasks)],
250                            rnp->grplo, rnp->grphi, rnp->grpnum);
251         }
252         seq_puts(m, "\n");
253 }
254
255 static int show_rcuhier(struct seq_file *m, void *unused)
256 {
257 #ifdef CONFIG_TREE_PREEMPT_RCU
258         seq_puts(m, "rcu_preempt:\n");
259         print_one_rcu_state(m, &rcu_preempt_state);
260 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
261         seq_puts(m, "rcu_sched:\n");
262         print_one_rcu_state(m, &rcu_sched_state);
263         seq_puts(m, "rcu_bh:\n");
264         print_one_rcu_state(m, &rcu_bh_state);
265         return 0;
266 }
267
268 static int rcuhier_open(struct inode *inode, struct file *file)
269 {
270         return single_open(file, show_rcuhier, NULL);
271 }
272
273 static const struct file_operations rcuhier_fops = {
274         .owner = THIS_MODULE,
275         .open = rcuhier_open,
276         .read = seq_read,
277         .llseek = seq_lseek,
278         .release = single_release,
279 };
280
281 static int show_rcugp(struct seq_file *m, void *unused)
282 {
283 #ifdef CONFIG_TREE_PREEMPT_RCU
284         seq_printf(m, "rcu_preempt: completed=%ld  gpnum=%lu\n",
285                    rcu_preempt_state.completed, rcu_preempt_state.gpnum);
286 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
287         seq_printf(m, "rcu_sched: completed=%ld  gpnum=%lu\n",
288                    rcu_sched_state.completed, rcu_sched_state.gpnum);
289         seq_printf(m, "rcu_bh: completed=%ld  gpnum=%lu\n",
290                    rcu_bh_state.completed, rcu_bh_state.gpnum);
291         return 0;
292 }
293
294 static int rcugp_open(struct inode *inode, struct file *file)
295 {
296         return single_open(file, show_rcugp, NULL);
297 }
298
299 static const struct file_operations rcugp_fops = {
300         .owner = THIS_MODULE,
301         .open = rcugp_open,
302         .read = seq_read,
303         .llseek = seq_lseek,
304         .release = single_release,
305 };
306
307 static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
308 {
309         seq_printf(m, "%3d%cnp=%ld "
310                    "qsp=%ld rpq=%ld cbr=%ld cng=%ld "
311                    "gpc=%ld gps=%ld nf=%ld nn=%ld\n",
312                    rdp->cpu,
313                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
314                    rdp->n_rcu_pending,
315                    rdp->n_rp_qs_pending,
316                    rdp->n_rp_report_qs,
317                    rdp->n_rp_cb_ready,
318                    rdp->n_rp_cpu_needs_gp,
319                    rdp->n_rp_gp_completed,
320                    rdp->n_rp_gp_started,
321                    rdp->n_rp_need_fqs,
322                    rdp->n_rp_need_nothing);
323 }
324
325 static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
326 {
327         int cpu;
328         struct rcu_data *rdp;
329
330         for_each_possible_cpu(cpu) {
331                 rdp = per_cpu_ptr(rsp->rda, cpu);
332                 if (rdp->beenonline)
333                         print_one_rcu_pending(m, rdp);
334         }
335 }
336
337 static int show_rcu_pending(struct seq_file *m, void *unused)
338 {
339 #ifdef CONFIG_TREE_PREEMPT_RCU
340         seq_puts(m, "rcu_preempt:\n");
341         print_rcu_pendings(m, &rcu_preempt_state);
342 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
343         seq_puts(m, "rcu_sched:\n");
344         print_rcu_pendings(m, &rcu_sched_state);
345         seq_puts(m, "rcu_bh:\n");
346         print_rcu_pendings(m, &rcu_bh_state);
347         return 0;
348 }
349
350 static int rcu_pending_open(struct inode *inode, struct file *file)
351 {
352         return single_open(file, show_rcu_pending, NULL);
353 }
354
355 static const struct file_operations rcu_pending_fops = {
356         .owner = THIS_MODULE,
357         .open = rcu_pending_open,
358         .read = seq_read,
359         .llseek = seq_lseek,
360         .release = single_release,
361 };
362
363 static struct dentry *rcudir;
364
365 static int __init rcutree_trace_init(void)
366 {
367         struct dentry *retval;
368
369         rcudir = debugfs_create_dir("rcu", NULL);
370         if (!rcudir)
371                 goto free_out;
372
373         retval = debugfs_create_file("rcudata", 0444, rcudir,
374                                                 NULL, &rcudata_fops);
375         if (!retval)
376                 goto free_out;
377
378         retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
379                                                 NULL, &rcudata_csv_fops);
380         if (!retval)
381                 goto free_out;
382
383         if (rcu_boost_trace_create_file(rcudir))
384                 goto free_out;
385
386         retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
387         if (!retval)
388                 goto free_out;
389
390         retval = debugfs_create_file("rcuhier", 0444, rcudir,
391                                                 NULL, &rcuhier_fops);
392         if (!retval)
393                 goto free_out;
394
395         retval = debugfs_create_file("rcu_pending", 0444, rcudir,
396                                                 NULL, &rcu_pending_fops);
397         if (!retval)
398                 goto free_out;
399         return 0;
400 free_out:
401         debugfs_remove_recursive(rcudir);
402         return 1;
403 }
404
405 static void __exit rcutree_trace_cleanup(void)
406 {
407         debugfs_remove_recursive(rcudir);
408 }
409
410
411 module_init(rcutree_trace_init);
412 module_exit(rcutree_trace_cleanup);
413
414 MODULE_AUTHOR("Paul E. McKenney");
415 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
416 MODULE_LICENSE("GPL");