linux/kernel/rcutree_trace.c
<<
>>
Prefs
   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
  51static 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
  60static 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
 106static 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
 119static int rcudata_open(struct inode *inode, struct file *file)
 120{
 121        return single_open(file, show_rcudata, NULL);
 122}
 123
 124static 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
 132static 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
 167static 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
 187static int rcudata_csv_open(struct inode *inode, struct file *file)
 188{
 189        return single_open(file, show_rcudata_csv, NULL);
 190}
 191
 192static 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
 202static 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
 226static 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
 235static int rcu_node_boost_open(struct inode *inode, struct file *file)
 236{
 237        return single_open(file, show_rcu_node_boost, NULL);
 238}
 239
 240static 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 */
 251static 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
 259static 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
 266static 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
 296static 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
 309static int rcuhier_open(struct inode *inode, struct file *file)
 310{
 311        return single_open(file, show_rcuhier, NULL);
 312}
 313
 314static 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
 322static 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
 344static 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
 354static int rcugp_open(struct inode *inode, struct file *file)
 355{
 356        return single_open(file, show_rcugp, NULL);
 357}
 358
 359static 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
 367static 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
 385static 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
 397static 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
 410static int rcu_pending_open(struct inode *inode, struct file *file)
 411{
 412        return single_open(file, show_rcu_pending, NULL);
 413}
 414
 415static 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
 423static 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
 433static int rcutorture_open(struct inode *inode, struct file *file)
 434{
 435        return single_open(file, show_rcutorture, NULL);
 436}
 437
 438static 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
 446static struct dentry *rcudir;
 447
 448static 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;
 488free_out:
 489        debugfs_remove_recursive(rcudir);
 490        return 1;
 491}
 492
 493static void __exit rcutree_trace_cleanup(void)
 494{
 495        debugfs_remove_recursive(rcudir);
 496}
 497
 498
 499module_init(rcutree_trace_init);
 500module_exit(rcutree_trace_cleanup);
 501
 502MODULE_AUTHOR("Paul E. McKenney");
 503MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
 504MODULE_LICENSE("GPL");
 505
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.