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 <linux/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 int show_rcubarrier(struct seq_file *m, void *unused)
  50 {
  51         struct rcu_state *rsp;
  52
  53         for_each_rcu_flavor(rsp)
  54                 seq_printf(m, "%s: bcc: %d nbd: %lu\n",
  55                            rsp->name,
  56                            atomic_read(&rsp->barrier_cpu_count),
  57                            rsp->n_barrier_done);
  58         return 0;
  59 }
  60
  61 static int rcubarrier_open(struct inode *inode, struct file *file)
  62 {
  63         return single_open(file, show_rcubarrier, NULL);
  64 }
  65
  66 static const struct file_operations rcubarrier_fops = {
  67         .owner = THIS_MODULE,
  68         .open = rcubarrier_open,
  69         .read = seq_read,
  70         .llseek = seq_lseek,
  71         .release = single_release,
  72 };
  73
  74 #ifdef CONFIG_RCU_BOOST
  75
  76 static char convert_kthread_status(unsigned int kthread_status)
  77 {
  78         if (kthread_status > RCU_KTHREAD_MAX)
  79                 return '?';
  80         return "SRWOY"[kthread_status];
  81 }
  82
  83 #endif /* #ifdef CONFIG_RCU_BOOST */
  84
  85 static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
  86 {
  87         if (!rdp->beenonline)
  88                 return;
  89         seq_printf(m, "%3d%cc=%lu g=%lu pq=%d qp=%d",
  90                    rdp->cpu,
  91                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
  92                    rdp->completed, rdp->gpnum,
  93                    rdp->passed_quiesce, rdp->qs_pending);
  94         seq_printf(m, " dt=%d/%llx/%d df=%lu",
  95                    atomic_read(&rdp->dynticks->dynticks),
  96                    rdp->dynticks->dynticks_nesting,
  97                    rdp->dynticks->dynticks_nmi_nesting,
  98                    rdp->dynticks_fqs);
  99         seq_printf(m, " of=%lu", rdp->offline_fqs);
 100         seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c",
 101                    rdp->qlen_lazy, rdp->qlen,
 102                    ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
 103                         rdp->nxttail[RCU_NEXT_TAIL]],
 104                    ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
 105                         rdp->nxttail[RCU_NEXT_READY_TAIL]],
 106                    ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
 107                         rdp->nxttail[RCU_WAIT_TAIL]],
 108                    ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
 109 #ifdef CONFIG_RCU_BOOST
 110         seq_printf(m, " kt=%d/%c/%d ktl=%x",
 111                    per_cpu(rcu_cpu_has_work, rdp->cpu),
 112                    convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
 113                                           rdp->cpu)),
 114                    per_cpu(rcu_cpu_kthread_cpu, rdp->cpu),
 115                    per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
 116 #endif /* #ifdef CONFIG_RCU_BOOST */
 117         seq_printf(m, " b=%ld", rdp->blimit);
 118         seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
 119                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
 120 }
 121
 122 static int show_rcudata(struct seq_file *m, void *unused)
 123 {
 124         int cpu;
 125         struct rcu_state *rsp;
 126
 127         for_each_rcu_flavor(rsp) {
 128                 seq_printf(m, "%s:\n", rsp->name);
 129                 for_each_possible_cpu(cpu)
 130                         print_one_rcu_data(m, per_cpu_ptr(rsp->rda, cpu));
 131         }
 132         return 0;
 133 }
 134
 135 static int rcudata_open(struct inode *inode, struct file *file)
 136 {
 137         return single_open(file, show_rcudata, NULL);
 138 }
 139
 140 static const struct file_operations rcudata_fops = {
 141         .owner = THIS_MODULE,
 142         .open = rcudata_open,
 143         .read = seq_read,
 144         .llseek = seq_lseek,
 145         .release = single_release,
 146 };
 147
 148 static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
 149 {
 150         if (!rdp->beenonline)
 151                 return;
 152         seq_printf(m, "%d,%s,%lu,%lu,%d,%d",
 153                    rdp->cpu,
 154                    cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
 155                    rdp->completed, rdp->gpnum,
 156                    rdp->passed_quiesce, rdp->qs_pending);
 157         seq_printf(m, ",%d,%llx,%d,%lu",
 158                    atomic_read(&rdp->dynticks->dynticks),
 159                    rdp->dynticks->dynticks_nesting,
 160                    rdp->dynticks->dynticks_nmi_nesting,
 161                    rdp->dynticks_fqs);
 162         seq_printf(m, ",%lu", rdp->offline_fqs);
 163         seq_printf(m, ",%ld,%ld,\"%c%c%c%c\"", rdp->qlen_lazy, rdp->qlen,
 164                    ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
 165                         rdp->nxttail[RCU_NEXT_TAIL]],
 166                    ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
 167                         rdp->nxttail[RCU_NEXT_READY_TAIL]],
 168                    ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
 169                         rdp->nxttail[RCU_WAIT_TAIL]],
 170                    ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
 171 #ifdef CONFIG_RCU_BOOST
 172         seq_printf(m, ",%d,\"%c\"",
 173                    per_cpu(rcu_cpu_has_work, rdp->cpu),
 174                    convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
 175                                           rdp->cpu)));
 176 #endif /* #ifdef CONFIG_RCU_BOOST */
 177         seq_printf(m, ",%ld", rdp->blimit);
 178         seq_printf(m, ",%lu,%lu,%lu\n",
 179                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
 180 }
 181
 182 static int show_rcudata_csv(struct seq_file *m, void *unused)
 183 {
 184         int cpu;
 185         struct rcu_state *rsp;
 186
 187         seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pq\",");
 188         seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");
 189         seq_puts(m, "\"of\",\"qll\",\"ql\",\"qs\"");
 190 #ifdef CONFIG_RCU_BOOST
 191         seq_puts(m, "\"kt\",\"ktl\"");
 192 #endif /* #ifdef CONFIG_RCU_BOOST */
 193         seq_puts(m, ",\"b\",\"ci\",\"co\",\"ca\"\n");
 194         for_each_rcu_flavor(rsp) {
 195                 seq_printf(m, "\"%s:\"\n", rsp->name);
 196                 for_each_possible_cpu(cpu)
 197                         print_one_rcu_data_csv(m, per_cpu_ptr(rsp->rda, cpu));
 198         }
 199         return 0;
 200 }
 201
 202 static int rcudata_csv_open(struct inode *inode, struct file *file)
 203 {
 204         return single_open(file, show_rcudata_csv, NULL);
 205 }
 206
 207 static const struct file_operations rcudata_csv_fops = {
 208         .owner = THIS_MODULE,
 209         .open = rcudata_csv_open,
 210         .read = seq_read,
 211         .llseek = seq_lseek,
 212         .release = single_release,
 213 };
 214
 215 #ifdef CONFIG_RCU_BOOST
 216
 217 static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
 218 {
 219         seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ",
 220                    rnp->grplo, rnp->grphi,
 221                    "T."[list_empty(&rnp->blkd_tasks)],
 222                    "N."[!rnp->gp_tasks],
 223                    "E."[!rnp->exp_tasks],
 224                    "B."[!rnp->boost_tasks],
 225                    convert_kthread_status(rnp->boost_kthread_status),
 226                    rnp->n_tasks_boosted, rnp->n_exp_boosts,
 227                    rnp->n_normal_boosts);
 228         seq_printf(m, "j=%04x bt=%04x\n",
 229                    (int)(jiffies & 0xffff),
 230                    (int)(rnp->boost_time & 0xffff));
 231         seq_printf(m, "    balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
 232                    rnp->n_balk_blkd_tasks,
 233                    rnp->n_balk_exp_gp_tasks,
 234                    rnp->n_balk_boost_tasks,
 235                    rnp->n_balk_notblocked,
 236                    rnp->n_balk_notyet,
 237                    rnp->n_balk_nos);
 238 }
 239
 240 static int show_rcu_node_boost(struct seq_file *m, void *unused)
 241 {
 242         struct rcu_node *rnp;
 243
 244         rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
 245                 print_one_rcu_node_boost(m, rnp);
 246         return 0;
 247 }
 248
 249 static int rcu_node_boost_open(struct inode *inode, struct file *file)
 250 {
 251         return single_open(file, show_rcu_node_boost, NULL);
 252 }
 253
 254 static const struct file_operations rcu_node_boost_fops = {
 255         .owner = THIS_MODULE,
 256         .open = rcu_node_boost_open,
 257         .read = seq_read,
 258         .llseek = seq_lseek,
 259         .release = single_release,
 260 };
 261
 262 /*
 263  * Create the rcuboost debugfs entry.  Standard error return.
 264  */
 265 static int rcu_boost_trace_create_file(struct dentry *rcudir)
 266 {
 267         return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
 268                                     &rcu_node_boost_fops);
 269 }
 270
 271 #else /* #ifdef CONFIG_RCU_BOOST */
 272
 273 static int rcu_boost_trace_create_file(struct dentry *rcudir)
 274 {
 275         return 0;  /* There cannot be an error if we didn't create it! */
 276 }
 277
 278 #endif /* #else #ifdef CONFIG_RCU_BOOST */
 279
 280 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
 281 {
 282         unsigned long gpnum;
 283         int level = 0;
 284         struct rcu_node *rnp;
 285
 286         gpnum = rsp->gpnum;
 287         seq_printf(m, "%s: c=%lu g=%lu s=%d jfq=%ld j=%x ",
 288                    rsp->name, rsp->completed, gpnum, rsp->fqs_state,
 289                    (long)(rsp->jiffies_force_qs - jiffies),
 290                    (int)(jiffies & 0xffff));
 291         seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
 292                    rsp->n_force_qs, rsp->n_force_qs_ngp,
 293                    rsp->n_force_qs - rsp->n_force_qs_ngp,
 294                    rsp->n_force_qs_lh, rsp->qlen_lazy, rsp->qlen);
 295         for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
 296                 if (rnp->level != level) {
 297                         seq_puts(m, "\n");
 298                         level = rnp->level;
 299                 }
 300                 seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d    ",
 301                            rnp->qsmask, rnp->qsmaskinit,
 302                            ".G"[rnp->gp_tasks != NULL],
 303                            ".E"[rnp->exp_tasks != NULL],
 304                            ".T"[!list_empty(&rnp->blkd_tasks)],
 305                            rnp->grplo, rnp->grphi, rnp->grpnum);
 306         }
 307         seq_puts(m, "\n");
 308 }
 309
 310 static int show_rcuhier(struct seq_file *m, void *unused)
 311 {
 312         struct rcu_state *rsp;
 313
 314         for_each_rcu_flavor(rsp)
 315                 print_one_rcu_state(m, rsp);
 316         return 0;
 317 }
 318
 319 static int rcuhier_open(struct inode *inode, struct file *file)
 320 {
 321         return single_open(file, show_rcuhier, NULL);
 322 }
 323
 324 static const struct file_operations rcuhier_fops = {
 325         .owner = THIS_MODULE,
 326         .open = rcuhier_open,
 327         .read = seq_read,
 328         .llseek = seq_lseek,
 329         .release = single_release,
 330 };
 331
 332 static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
 333 {
 334         unsigned long flags;
 335         unsigned long completed;
 336         unsigned long gpnum;
 337         unsigned long gpage;
 338         unsigned long gpmax;
 339         struct rcu_node *rnp = &rsp->node[0];
 340
 341         raw_spin_lock_irqsave(&rnp->lock, flags);
 342         completed = rsp->completed;
 343         gpnum = rsp->gpnum;
 344         if (rsp->completed == rsp->gpnum)
 345                 gpage = 0;
 346         else
 347                 gpage = jiffies - rsp->gp_start;
 348         gpmax = rsp->gp_max;
 349         raw_spin_unlock_irqrestore(&rnp->lock, flags);
 350         seq_printf(m, "%s: completed=%ld  gpnum=%lu  age=%ld  max=%ld\n",
 351                    rsp->name, completed, gpnum, gpage, gpmax);
 352 }
 353
 354 static int show_rcugp(struct seq_file *m, void *unused)
 355 {
 356         struct rcu_state *rsp;
 357
 358         for_each_rcu_flavor(rsp)
 359                 show_one_rcugp(m, rsp);
 360         return 0;
 361 }
 362
 363 static int rcugp_open(struct inode *inode, struct file *file)
 364 {
 365         return single_open(file, show_rcugp, NULL);
 366 }
 367
 368 static const struct file_operations rcugp_fops = {
 369         .owner = THIS_MODULE,
 370         .open = rcugp_open,
 371         .read = seq_read,
 372         .llseek = seq_lseek,
 373         .release = single_release,
 374 };
 375
 376 static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
 377 {
 378         seq_printf(m, "%3d%cnp=%ld ",
 379                    rdp->cpu,
 380                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
 381                    rdp->n_rcu_pending);
 382         seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
 383                    rdp->n_rp_qs_pending,
 384                    rdp->n_rp_report_qs,
 385                    rdp->n_rp_cb_ready,
 386                    rdp->n_rp_cpu_needs_gp);
 387         seq_printf(m, "gpc=%ld gps=%ld nn=%ld\n",
 388                    rdp->n_rp_gp_completed,
 389                    rdp->n_rp_gp_started,
 390                    rdp->n_rp_need_nothing);
 391 }
 392
 393 static int show_rcu_pending(struct seq_file *m, void *unused)
 394 {
 395         int cpu;
 396         struct rcu_data *rdp;
 397         struct rcu_state *rsp;
 398
 399         for_each_rcu_flavor(rsp) {
 400                 seq_printf(m, "%s:\n", rsp->name);
 401                 for_each_possible_cpu(cpu) {
 402                         rdp = per_cpu_ptr(rsp->rda, cpu);
 403                         if (rdp->beenonline)
 404                                 print_one_rcu_pending(m, rdp);
 405                 }
 406         }
 407         return 0;
 408 }
 409
 410 static int rcu_pending_open(struct inode *inode, struct file *file)
 411 {
 412         return single_open(file, show_rcu_pending, NULL);
 413 }
 414
 415 static const struct file_operations rcu_pending_fops = {
 416         .owner = THIS_MODULE,
 417         .open = rcu_pending_open,
 418         .read = seq_read,
 419         .llseek = seq_lseek,
 420         .release = single_release,
 421 };
 422
 423 static int show_rcutorture(struct seq_file *m, void *unused)
 424 {
 425         seq_printf(m, "rcutorture test sequence: %lu %s\n",
 426                    rcutorture_testseq >> 1,
 427                    (rcutorture_testseq & 0x1) ? "(test in progress)" : "");
 428         seq_printf(m, "rcutorture update version number: %lu\n",
 429                    rcutorture_vernum);
 430         return 0;
 431 }
 432
 433 static int rcutorture_open(struct inode *inode, struct file *file)
 434 {
 435         return single_open(file, show_rcutorture, NULL);
 436 }
 437
 438 static const struct file_operations rcutorture_fops = {
 439         .owner = THIS_MODULE,
 440         .open = rcutorture_open,
 441         .read = seq_read,
 442         .llseek = seq_lseek,
 443         .release = single_release,
 444 };
 445
 446 static struct dentry *rcudir;
 447
 448 static int __init rcutree_trace_init(void)
 449 {
 450         struct dentry *retval;
 451
 452         rcudir = debugfs_create_dir("rcu", NULL);
 453         if (!rcudir)
 454                 goto free_out;
 455
 456         retval = debugfs_create_file("rcubarrier", 0444, rcudir,
 457                                                 NULL, &rcubarrier_fops);
 458         if (!retval)
 459                 goto free_out;
 460
 461         retval = debugfs_create_file("rcudata", 0444, rcudir,
 462                                                 NULL, &rcudata_fops);
 463         if (!retval)
 464                 goto free_out;
 465
 466         retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
 467                                                 NULL, &rcudata_csv_fops);
 468         if (!retval)
 469                 goto free_out;
 470
 471         if (rcu_boost_trace_create_file(rcudir))
 472                 goto free_out;
 473
 474         retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
 475         if (!retval)
 476                 goto free_out;
 477
 478         retval = debugfs_create_file("rcuhier", 0444, rcudir,
 479                                                 NULL, &rcuhier_fops);
 480         if (!retval)
 481                 goto free_out;
 482
 483         retval = debugfs_create_file("rcu_pending", 0444, rcudir,
 484                                                 NULL, &rcu_pending_fops);
 485         if (!retval)
 486                 goto free_out;
 487
 488         retval = debugfs_create_file("rcutorture", 0444, rcudir,
 489                                                 NULL, &rcutorture_fops);
 490         if (!retval)
 491                 goto free_out;
 492         return 0;
 493 free_out:
 494         debugfs_remove_recursive(rcudir);
 495         return 1;
 496 }
 497
 498 static void __exit rcutree_trace_cleanup(void)
 499 {
 500         debugfs_remove_recursive(rcudir);
 501 }
 502
 503
 504 module_init(rcutree_trace_init);
 505 module_exit(rcutree_trace_cleanup);
 506
 507 MODULE_AUTHOR("Paul E. McKenney");
 508 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
 509 MODULE_LICENSE("GPL");