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