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