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