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
  49static int r_open(struct inode *inode, struct file *file,
  50                                        const struct seq_operations *op)
  51{
  52        int ret = seq_open(file, op);
  53        if (!ret) {
  54                struct seq_file *m = (struct seq_file *)file->private_data;
  55                m->private = inode->i_private;
  56        }
  57        return ret;
  58}
  59
  60static void *r_start(struct seq_file *m, loff_t *pos)
  61{
  62        struct rcu_state *rsp = (struct rcu_state *)m->private;
  63        *pos = cpumask_next(*pos - 1, cpu_possible_mask);
  64        if ((*pos) < nr_cpu_ids)
  65                return per_cpu_ptr(rsp->rda, *pos);
  66        return NULL;
  67}
  68
  69static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  70{
  71        (*pos)++;
  72        return r_start(m, pos);
  73}
  74
  75static void r_stop(struct seq_file *m, void *v)
  76{
  77}
  78
  79static int show_rcubarrier(struct seq_file *m, void *v)
  80{
  81        struct rcu_state *rsp = (struct rcu_state *)m->private;
  82        seq_printf(m, "bcc: %d nbd: %lu\n",
  83                   atomic_read(&rsp->barrier_cpu_count),
  84                   rsp->n_barrier_done);
  85        return 0;
  86}
  87
  88static int rcubarrier_open(struct inode *inode, struct file *file)
  89{
  90        return single_open(file, show_rcubarrier, inode->i_private);
  91}
  92
  93static const struct file_operations rcubarrier_fops = {
  94        .owner = THIS_MODULE,
  95        .open = rcubarrier_open,
  96        .read = seq_read,
  97        .llseek = no_llseek,
  98        .release = single_release,
  99};
 100
 101#ifdef CONFIG_RCU_BOOST
 102
 103static char convert_kthread_status(unsigned int kthread_status)
 104{
 105        if (kthread_status > RCU_KTHREAD_MAX)
 106                return '?';
 107        return "SRWOY"[kthread_status];
 108}
 109
 110#endif /* #ifdef CONFIG_RCU_BOOST */
 111
 112static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
 113{
 114        long ql, qll;
 115
 116        if (!rdp->beenonline)
 117                return;
 118        seq_printf(m, "%3d%cc=%ld g=%ld pq=%d qp=%d",
 119                   rdp->cpu,
 120                   cpu_is_offline(rdp->cpu) ? '!' : ' ',
 121                   ulong2long(rdp->completed), ulong2long(rdp->gpnum),
 122                   rdp->passed_quiesce, rdp->qs_pending);
 123        seq_printf(m, " dt=%d/%llx/%d df=%lu",
 124                   atomic_read(&rdp->dynticks->dynticks),
 125                   rdp->dynticks->dynticks_nesting,
 126                   rdp->dynticks->dynticks_nmi_nesting,
 127                   rdp->dynticks_fqs);
 128        seq_printf(m, " of=%lu", rdp->offline_fqs);
 129        rcu_nocb_q_lengths(rdp, &ql, &qll);
 130        qll += rdp->qlen_lazy;
 131        ql += rdp->qlen;
 132        seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c",
 133                   qll, ql,
 134                   ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
 135                        rdp->nxttail[RCU_NEXT_TAIL]],
 136                   ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
 137                        rdp->nxttail[RCU_NEXT_READY_TAIL]],
 138                   ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
 139                        rdp->nxttail[RCU_WAIT_TAIL]],
 140                   ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
 141#ifdef CONFIG_RCU_BOOST
 142        seq_printf(m, " kt=%d/%c ktl=%x",
 143                   per_cpu(rcu_cpu_has_work, rdp->cpu),
 144                   convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
 145                                          rdp->cpu)),
 146                   per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
 147#endif /* #ifdef CONFIG_RCU_BOOST */
 148        seq_printf(m, " b=%ld", rdp->blimit);
 149        seq_printf(m, " ci=%lu nci=%lu co=%lu ca=%lu\n",
 150                   rdp->n_cbs_invoked, rdp->n_nocbs_invoked,
 151                   rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
 152}
 153
 154static int show_rcudata(struct seq_file *m, void *v)
 155{
 156        print_one_rcu_data(m, (struct rcu_data *)v);
 157        return 0;
 158}
 159
 160static const struct seq_operations rcudate_op = {
 161        .start = r_start,
 162        .next  = r_next,
 163        .stop  = r_stop,
 164        .show  = show_rcudata,
 165};
 166
 167static int rcudata_open(struct inode *inode, struct file *file)
 168{
 169        return r_open(inode, file, &rcudate_op);
 170}
 171
 172static const struct file_operations rcudata_fops = {
 173        .owner = THIS_MODULE,
 174        .open = rcudata_open,
 175        .read = seq_read,
 176        .llseek = no_llseek,
 177        .release = seq_release,
 178};
 179
 180static int show_rcuexp(struct seq_file *m, void *v)
 181{
 182        struct rcu_state *rsp = (struct rcu_state *)m->private;
 183
 184        seq_printf(m, "s=%lu d=%lu w=%lu tf=%lu wd1=%lu wd2=%lu n=%lu sc=%lu dt=%lu dl=%lu dx=%lu\n",
 185                   atomic_long_read(&rsp->expedited_start),
 186                   atomic_long_read(&rsp->expedited_done),
 187                   atomic_long_read(&rsp->expedited_wrap),
 188                   atomic_long_read(&rsp->expedited_tryfail),
 189                   atomic_long_read(&rsp->expedited_workdone1),
 190                   atomic_long_read(&rsp->expedited_workdone2),
 191                   atomic_long_read(&rsp->expedited_normal),
 192                   atomic_long_read(&rsp->expedited_stoppedcpus),
 193                   atomic_long_read(&rsp->expedited_done_tries),
 194                   atomic_long_read(&rsp->expedited_done_lost),
 195                   atomic_long_read(&rsp->expedited_done_exit));
 196        return 0;
 197}
 198
 199static int rcuexp_open(struct inode *inode, struct file *file)
 200{
 201        return single_open(file, show_rcuexp, inode->i_private);
 202}
 203
 204static const struct file_operations rcuexp_fops = {
 205        .owner = THIS_MODULE,
 206        .open = rcuexp_open,
 207        .read = seq_read,
 208        .llseek = no_llseek,
 209        .release = single_release,
 210};
 211
 212#ifdef CONFIG_RCU_BOOST
 213
 214static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
 215{
 216        seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ",
 217                   rnp->grplo, rnp->grphi,
 218                   "T."[list_empty(&rnp->blkd_tasks)],
 219                   "N."[!rnp->gp_tasks],
 220                   "E."[!rnp->exp_tasks],
 221                   "B."[!rnp->boost_tasks],
 222                   convert_kthread_status(rnp->boost_kthread_status),
 223                   rnp->n_tasks_boosted, rnp->n_exp_boosts,
 224                   rnp->n_normal_boosts);
 225        seq_printf(m, "j=%04x bt=%04x\n",
 226                   (int)(jiffies & 0xffff),
 227                   (int)(rnp->boost_time & 0xffff));
 228        seq_printf(m, "    balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
 229                   rnp->n_balk_blkd_tasks,
 230                   rnp->n_balk_exp_gp_tasks,
 231                   rnp->n_balk_boost_tasks,
 232                   rnp->n_balk_notblocked,
 233                   rnp->n_balk_notyet,
 234                   rnp->n_balk_nos);
 235}
 236
 237static int show_rcu_node_boost(struct seq_file *m, void *unused)
 238{
 239        struct rcu_node *rnp;
 240
 241        rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
 242                print_one_rcu_node_boost(m, rnp);
 243        return 0;
 244}
 245
 246static int rcu_node_boost_open(struct inode *inode, struct file *file)
 247{
 248        return single_open(file, show_rcu_node_boost, NULL);
 249}
 250
 251static const struct file_operations rcu_node_boost_fops = {
 252        .owner = THIS_MODULE,
 253        .open = rcu_node_boost_open,
 254        .read = seq_read,
 255        .llseek = no_llseek,
 256        .release = single_release,
 257};
 258
 259#endif /* #ifdef CONFIG_RCU_BOOST */
 260
 261static 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=%ld g=%ld s=%d jfq=%ld j=%x ",
 269                   ulong2long(rsp->completed), ulong2long(gpnum),
 270                   rsp->fqs_state,
 271                   (long)(rsp->jiffies_force_qs - jiffies),
 272                   (int)(jiffies & 0xffff));
 273        seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
 274                   rsp->n_force_qs, rsp->n_force_qs_ngp,
 275                   rsp->n_force_qs - rsp->n_force_qs_ngp,
 276                   rsp->n_force_qs_lh, rsp->qlen_lazy, rsp->qlen);
 277        for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
 278                if (rnp->level != level) {
 279                        seq_puts(m, "\n");
 280                        level = rnp->level;
 281                }
 282                seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d    ",
 283                           rnp->qsmask, rnp->qsmaskinit,
 284                           ".G"[rnp->gp_tasks != NULL],
 285                           ".E"[rnp->exp_tasks != NULL],
 286                           ".T"[!list_empty(&rnp->blkd_tasks)],
 287                           rnp->grplo, rnp->grphi, rnp->grpnum);
 288        }
 289        seq_puts(m, "\n");
 290}
 291
 292static int show_rcuhier(struct seq_file *m, void *v)
 293{
 294        struct rcu_state *rsp = (struct rcu_state *)m->private;
 295        print_one_rcu_state(m, rsp);
 296        return 0;
 297}
 298
 299static int rcuhier_open(struct inode *inode, struct file *file)
 300{
 301        return single_open(file, show_rcuhier, inode->i_private);
 302}
 303
 304static const struct file_operations rcuhier_fops = {
 305        .owner = THIS_MODULE,
 306        .open = rcuhier_open,
 307        .read = seq_read,
 308        .llseek = no_llseek,
 309        .release = single_release,
 310};
 311
 312static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
 313{
 314        unsigned long flags;
 315        unsigned long completed;
 316        unsigned long gpnum;
 317        unsigned long gpage;
 318        unsigned long gpmax;
 319        struct rcu_node *rnp = &rsp->node[0];
 320
 321        raw_spin_lock_irqsave(&rnp->lock, flags);
 322        completed = ACCESS_ONCE(rsp->completed);
 323        gpnum = ACCESS_ONCE(rsp->gpnum);
 324        if (completed == gpnum)
 325                gpage = 0;
 326        else
 327                gpage = jiffies - rsp->gp_start;
 328        gpmax = rsp->gp_max;
 329        raw_spin_unlock_irqrestore(&rnp->lock, flags);
 330        seq_printf(m, "completed=%ld  gpnum=%ld  age=%ld  max=%ld\n",
 331                   ulong2long(completed), ulong2long(gpnum), gpage, gpmax);
 332}
 333
 334static int show_rcugp(struct seq_file *m, void *v)
 335{
 336        struct rcu_state *rsp = (struct rcu_state *)m->private;
 337        show_one_rcugp(m, rsp);
 338        return 0;
 339}
 340
 341static int rcugp_open(struct inode *inode, struct file *file)
 342{
 343        return single_open(file, show_rcugp, inode->i_private);
 344}
 345
 346static const struct file_operations rcugp_fops = {
 347        .owner = THIS_MODULE,
 348        .open = rcugp_open,
 349        .read = seq_read,
 350        .llseek = no_llseek,
 351        .release = single_release,
 352};
 353
 354static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
 355{
 356        if (!rdp->beenonline)
 357                return;
 358        seq_printf(m, "%3d%cnp=%ld ",
 359                   rdp->cpu,
 360                   cpu_is_offline(rdp->cpu) ? '!' : ' ',
 361                   rdp->n_rcu_pending);
 362        seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
 363                   rdp->n_rp_qs_pending,
 364                   rdp->n_rp_report_qs,
 365                   rdp->n_rp_cb_ready,
 366                   rdp->n_rp_cpu_needs_gp);
 367        seq_printf(m, "gpc=%ld gps=%ld nn=%ld\n",
 368                   rdp->n_rp_gp_completed,
 369                   rdp->n_rp_gp_started,
 370                   rdp->n_rp_need_nothing);
 371}
 372
 373static int show_rcu_pending(struct seq_file *m, void *v)
 374{
 375        print_one_rcu_pending(m, (struct rcu_data *)v);
 376        return 0;
 377}
 378
 379static const struct seq_operations rcu_pending_op = {
 380        .start = r_start,
 381        .next  = r_next,
 382        .stop  = r_stop,
 383        .show  = show_rcu_pending,
 384};
 385
 386static int rcu_pending_open(struct inode *inode, struct file *file)
 387{
 388        return r_open(inode, file, &rcu_pending_op);
 389}
 390
 391static const struct file_operations rcu_pending_fops = {
 392        .owner = THIS_MODULE,
 393        .open = rcu_pending_open,
 394        .read = seq_read,
 395        .llseek = no_llseek,
 396        .release = seq_release,
 397};
 398
 399static int show_rcutorture(struct seq_file *m, void *unused)
 400{
 401        seq_printf(m, "rcutorture test sequence: %lu %s\n",
 402                   rcutorture_testseq >> 1,
 403                   (rcutorture_testseq & 0x1) ? "(test in progress)" : "");
 404        seq_printf(m, "rcutorture update version number: %lu\n",
 405                   rcutorture_vernum);
 406        return 0;
 407}
 408
 409static int rcutorture_open(struct inode *inode, struct file *file)
 410{
 411        return single_open(file, show_rcutorture, NULL);
 412}
 413
 414static const struct file_operations rcutorture_fops = {
 415        .owner = THIS_MODULE,
 416        .open = rcutorture_open,
 417        .read = seq_read,
 418        .llseek = seq_lseek,
 419        .release = single_release,
 420};
 421
 422static struct dentry *rcudir;
 423
 424static int __init rcutree_trace_init(void)
 425{
 426        struct rcu_state *rsp;
 427        struct dentry *retval;
 428        struct dentry *rspdir;
 429
 430        rcudir = debugfs_create_dir("rcu", NULL);
 431        if (!rcudir)
 432                goto free_out;
 433
 434        for_each_rcu_flavor(rsp) {
 435                rspdir = debugfs_create_dir(rsp->name, rcudir);
 436                if (!rspdir)
 437                        goto free_out;
 438
 439                retval = debugfs_create_file("rcudata", 0444,
 440                                rspdir, rsp, &rcudata_fops);
 441                if (!retval)
 442                        goto free_out;
 443
 444                retval = debugfs_create_file("rcuexp", 0444,
 445                                rspdir, rsp, &rcuexp_fops);
 446                if (!retval)
 447                        goto free_out;
 448
 449                retval = debugfs_create_file("rcu_pending", 0444,
 450                                rspdir, rsp, &rcu_pending_fops);
 451                if (!retval)
 452                        goto free_out;
 453
 454                retval = debugfs_create_file("rcubarrier", 0444,
 455                                rspdir, rsp, &rcubarrier_fops);
 456                if (!retval)
 457                        goto free_out;
 458
 459#ifdef CONFIG_RCU_BOOST
 460                if (rsp == &rcu_preempt_state) {
 461                        retval = debugfs_create_file("rcuboost", 0444,
 462                                rspdir, NULL, &rcu_node_boost_fops);
 463                        if (!retval)
 464                                goto free_out;
 465                }
 466#endif
 467
 468                retval = debugfs_create_file("rcugp", 0444,
 469                                rspdir, rsp, &rcugp_fops);
 470                if (!retval)
 471                        goto free_out;
 472
 473                retval = debugfs_create_file("rcuhier", 0444,
 474                                rspdir, rsp, &rcuhier_fops);
 475                if (!retval)
 476                        goto free_out;
 477        }
 478
 479        retval = debugfs_create_file("rcutorture", 0444, rcudir,
 480                                                NULL, &rcutorture_fops);
 481        if (!retval)
 482                goto free_out;
 483        return 0;
 484free_out:
 485        debugfs_remove_recursive(rcudir);
 486        return 1;
 487}
 488
 489static void __exit rcutree_trace_cleanup(void)
 490{
 491        debugfs_remove_recursive(rcudir);
 492}
 493
 494
 495module_init(rcutree_trace_init);
 496module_exit(rcutree_trace_cleanup);
 497
 498MODULE_AUTHOR("Paul E. McKenney");
 499MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
 500MODULE_LICENSE("GPL");
 501
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.