linux/kernel/rcutree_trace.c
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   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
  49static 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
  61static int rcubarrier_open(struct inode *inode, struct file *file)
  62{
  63        return single_open(file, show_rcubarrier, NULL);
  64}
  65
  66static 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
  76static 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
  85static 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
 123static 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
 136static int rcudata_open(struct inode *inode, struct file *file)
 137{
 138        return single_open(file, show_rcudata, NULL);
 139}
 140
 141static 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
 149static 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
 184static 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
 204static int rcudata_csv_open(struct inode *inode, struct file *file)
 205{
 206        return single_open(file, show_rcudata_csv, NULL);
 207}
 208
 209static 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
 219static 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
 242static 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
 251static int rcu_node_boost_open(struct inode *inode, struct file *file)
 252{
 253        return single_open(file, show_rcu_node_boost, NULL);
 254}
 255
 256static 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 */
 267static 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
 275static 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
 282static 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
 312static 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
 321static int rcuhier_open(struct inode *inode, struct file *file)
 322{
 323        return single_open(file, show_rcuhier, NULL);
 324}
 325
 326static 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
 334static 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
 356static 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
 365static int rcugp_open(struct inode *inode, struct file *file)
 366{
 367        return single_open(file, show_rcugp, NULL);
 368}
 369
 370static 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
 378static 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
 396static 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
 413static int rcu_pending_open(struct inode *inode, struct file *file)
 414{
 415        return single_open(file, show_rcu_pending, NULL);
 416}
 417
 418static 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
 426static 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
 436static int rcutorture_open(struct inode *inode, struct file *file)
 437{
 438        return single_open(file, show_rcutorture, NULL);
 439}
 440
 441static 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
 449static struct dentry *rcudir;
 450
 451static 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;
 496free_out:
 497        debugfs_remove_recursive(rcudir);
 498        return 1;
 499}
 500
 501static void __exit rcutree_trace_cleanup(void)
 502{
 503        debugfs_remove_recursive(rcudir);
 504}
 505
 506
 507module_init(rcutree_trace_init);
 508module_exit(rcutree_trace_cleanup);
 509
 510MODULE_AUTHOR("Paul E. McKenney");
 511MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
 512MODULE_LICENSE("GPL");
 513
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