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