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