linux/kernel/rcutree_trace.c
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   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
  49static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
  50{
  51        if (!rdp->beenonline)
  52                return;
  53        seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pqc=%lu qp=%d",
  54                   rdp->cpu,
  55                   cpu_is_offline(rdp->cpu) ? '!' : ' ',
  56                   rdp->completed, rdp->gpnum,
  57                   rdp->passed_quiesc, rdp->passed_quiesc_completed,
  58                   rdp->qs_pending);
  59#ifdef CONFIG_NO_HZ
  60        seq_printf(m, " dt=%d/%d dn=%d df=%lu",
  61                   rdp->dynticks->dynticks,
  62                   rdp->dynticks->dynticks_nesting,
  63                   rdp->dynticks->dynticks_nmi,
  64                   rdp->dynticks_fqs);
  65#endif /* #ifdef CONFIG_NO_HZ */
  66        seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);
  67        seq_printf(m, " ql=%ld b=%ld\n", rdp->qlen, rdp->blimit);
  68}
  69
  70#define PRINT_RCU_DATA(name, func, m) \
  71        do { \
  72                int _p_r_d_i; \
  73                \
  74                for_each_possible_cpu(_p_r_d_i) \
  75                        func(m, &per_cpu(name, _p_r_d_i)); \
  76        } while (0)
  77
  78static int show_rcudata(struct seq_file *m, void *unused)
  79{
  80#ifdef CONFIG_TREE_PREEMPT_RCU
  81        seq_puts(m, "rcu_preempt:\n");
  82        PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data, m);
  83#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
  84        seq_puts(m, "rcu_sched:\n");
  85        PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data, m);
  86        seq_puts(m, "rcu_bh:\n");
  87        PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
  88        return 0;
  89}
  90
  91static int rcudata_open(struct inode *inode, struct file *file)
  92{
  93        return single_open(file, show_rcudata, NULL);
  94}
  95
  96static const struct file_operations rcudata_fops = {
  97        .owner = THIS_MODULE,
  98        .open = rcudata_open,
  99        .read = seq_read,
 100        .llseek = seq_lseek,
 101        .release = single_release,
 102};
 103
 104static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
 105{
 106        if (!rdp->beenonline)
 107                return;
 108        seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
 109                   rdp->cpu,
 110                   cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
 111                   rdp->completed, rdp->gpnum,
 112                   rdp->passed_quiesc, rdp->passed_quiesc_completed,
 113                   rdp->qs_pending);
 114#ifdef CONFIG_NO_HZ
 115        seq_printf(m, ",%d,%d,%d,%lu",
 116                   rdp->dynticks->dynticks,
 117                   rdp->dynticks->dynticks_nesting,
 118                   rdp->dynticks->dynticks_nmi,
 119                   rdp->dynticks_fqs);
 120#endif /* #ifdef CONFIG_NO_HZ */
 121        seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
 122        seq_printf(m, ",%ld,%ld\n", rdp->qlen, rdp->blimit);
 123}
 124
 125static int show_rcudata_csv(struct seq_file *m, void *unused)
 126{
 127        seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
 128#ifdef CONFIG_NO_HZ
 129        seq_puts(m, "\"dt\",\"dt nesting\",\"dn\",\"df\",");
 130#endif /* #ifdef CONFIG_NO_HZ */
 131        seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\"\n");
 132#ifdef CONFIG_TREE_PREEMPT_RCU
 133        seq_puts(m, "\"rcu_preempt:\"\n");
 134        PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data_csv, m);
 135#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 136        seq_puts(m, "\"rcu_sched:\"\n");
 137        PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data_csv, m);
 138        seq_puts(m, "\"rcu_bh:\"\n");
 139        PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
 140        return 0;
 141}
 142
 143static int rcudata_csv_open(struct inode *inode, struct file *file)
 144{
 145        return single_open(file, show_rcudata_csv, NULL);
 146}
 147
 148static const struct file_operations rcudata_csv_fops = {
 149        .owner = THIS_MODULE,
 150        .open = rcudata_csv_open,
 151        .read = seq_read,
 152        .llseek = seq_lseek,
 153        .release = single_release,
 154};
 155
 156static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
 157{
 158        unsigned long gpnum;
 159        int level = 0;
 160        int phase;
 161        struct rcu_node *rnp;
 162
 163        gpnum = rsp->gpnum;
 164        seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "
 165                      "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld\n",
 166                   rsp->completed, gpnum, rsp->signaled,
 167                   (long)(rsp->jiffies_force_qs - jiffies),
 168                   (int)(jiffies & 0xffff),
 169                   rsp->n_force_qs, rsp->n_force_qs_ngp,
 170                   rsp->n_force_qs - rsp->n_force_qs_ngp,
 171                   rsp->n_force_qs_lh, rsp->orphan_qlen);
 172        for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
 173                if (rnp->level != level) {
 174                        seq_puts(m, "\n");
 175                        level = rnp->level;
 176                }
 177                phase = gpnum & 0x1;
 178                seq_printf(m, "%lx/%lx %c%c>%c%c %d:%d ^%d    ",
 179                           rnp->qsmask, rnp->qsmaskinit,
 180                           "T."[list_empty(&rnp->blocked_tasks[phase])],
 181                           "E."[list_empty(&rnp->blocked_tasks[phase + 2])],
 182                           "T."[list_empty(&rnp->blocked_tasks[!phase])],
 183                           "E."[list_empty(&rnp->blocked_tasks[!phase + 2])],
 184                           rnp->grplo, rnp->grphi, rnp->grpnum);
 185        }
 186        seq_puts(m, "\n");
 187}
 188
 189static int show_rcuhier(struct seq_file *m, void *unused)
 190{
 191#ifdef CONFIG_TREE_PREEMPT_RCU
 192        seq_puts(m, "rcu_preempt:\n");
 193        print_one_rcu_state(m, &rcu_preempt_state);
 194#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 195        seq_puts(m, "rcu_sched:\n");
 196        print_one_rcu_state(m, &rcu_sched_state);
 197        seq_puts(m, "rcu_bh:\n");
 198        print_one_rcu_state(m, &rcu_bh_state);
 199        return 0;
 200}
 201
 202static int rcuhier_open(struct inode *inode, struct file *file)
 203{
 204        return single_open(file, show_rcuhier, NULL);
 205}
 206
 207static const struct file_operations rcuhier_fops = {
 208        .owner = THIS_MODULE,
 209        .open = rcuhier_open,
 210        .read = seq_read,
 211        .llseek = seq_lseek,
 212        .release = single_release,
 213};
 214
 215static int show_rcugp(struct seq_file *m, void *unused)
 216{
 217#ifdef CONFIG_TREE_PREEMPT_RCU
 218        seq_printf(m, "rcu_preempt: completed=%ld  gpnum=%lu\n",
 219                   rcu_preempt_state.completed, rcu_preempt_state.gpnum);
 220#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 221        seq_printf(m, "rcu_sched: completed=%ld  gpnum=%lu\n",
 222                   rcu_sched_state.completed, rcu_sched_state.gpnum);
 223        seq_printf(m, "rcu_bh: completed=%ld  gpnum=%lu\n",
 224                   rcu_bh_state.completed, rcu_bh_state.gpnum);
 225        return 0;
 226}
 227
 228static int rcugp_open(struct inode *inode, struct file *file)
 229{
 230        return single_open(file, show_rcugp, NULL);
 231}
 232
 233static const struct file_operations rcugp_fops = {
 234        .owner = THIS_MODULE,
 235        .open = rcugp_open,
 236        .read = seq_read,
 237        .llseek = seq_lseek,
 238        .release = single_release,
 239};
 240
 241static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
 242{
 243        seq_printf(m, "%3d%cnp=%ld "
 244                   "qsp=%ld rpq=%ld cbr=%ld cng=%ld "
 245                   "gpc=%ld gps=%ld nf=%ld nn=%ld\n",
 246                   rdp->cpu,
 247                   cpu_is_offline(rdp->cpu) ? '!' : ' ',
 248                   rdp->n_rcu_pending,
 249                   rdp->n_rp_qs_pending,
 250                   rdp->n_rp_report_qs,
 251                   rdp->n_rp_cb_ready,
 252                   rdp->n_rp_cpu_needs_gp,
 253                   rdp->n_rp_gp_completed,
 254                   rdp->n_rp_gp_started,
 255                   rdp->n_rp_need_fqs,
 256                   rdp->n_rp_need_nothing);
 257}
 258
 259static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
 260{
 261        int cpu;
 262        struct rcu_data *rdp;
 263
 264        for_each_possible_cpu(cpu) {
 265                rdp = rsp->rda[cpu];
 266                if (rdp->beenonline)
 267                        print_one_rcu_pending(m, rdp);
 268        }
 269}
 270
 271static int show_rcu_pending(struct seq_file *m, void *unused)
 272{
 273#ifdef CONFIG_TREE_PREEMPT_RCU
 274        seq_puts(m, "rcu_preempt:\n");
 275        print_rcu_pendings(m, &rcu_preempt_state);
 276#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 277        seq_puts(m, "rcu_sched:\n");
 278        print_rcu_pendings(m, &rcu_sched_state);
 279        seq_puts(m, "rcu_bh:\n");
 280        print_rcu_pendings(m, &rcu_bh_state);
 281        return 0;
 282}
 283
 284static int rcu_pending_open(struct inode *inode, struct file *file)
 285{
 286        return single_open(file, show_rcu_pending, NULL);
 287}
 288
 289static const struct file_operations rcu_pending_fops = {
 290        .owner = THIS_MODULE,
 291        .open = rcu_pending_open,
 292        .read = seq_read,
 293        .llseek = seq_lseek,
 294        .release = single_release,
 295};
 296
 297static struct dentry *rcudir;
 298
 299static int __init rcuclassic_trace_init(void)
 300{
 301        struct dentry *retval;
 302
 303        rcudir = debugfs_create_dir("rcu", NULL);
 304        if (!rcudir)
 305                goto free_out;
 306
 307        retval = debugfs_create_file("rcudata", 0444, rcudir,
 308                                                NULL, &rcudata_fops);
 309        if (!retval)
 310                goto free_out;
 311
 312        retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
 313                                                NULL, &rcudata_csv_fops);
 314        if (!retval)
 315                goto free_out;
 316
 317        retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
 318        if (!retval)
 319                goto free_out;
 320
 321        retval = debugfs_create_file("rcuhier", 0444, rcudir,
 322                                                NULL, &rcuhier_fops);
 323        if (!retval)
 324                goto free_out;
 325
 326        retval = debugfs_create_file("rcu_pending", 0444, rcudir,
 327                                                NULL, &rcu_pending_fops);
 328        if (!retval)
 329                goto free_out;
 330        return 0;
 331free_out:
 332        debugfs_remove_recursive(rcudir);
 333        return 1;
 334}
 335
 336static void __exit rcuclassic_trace_cleanup(void)
 337{
 338        debugfs_remove_recursive(rcudir);
 339}
 340
 341
 342module_init(rcuclassic_trace_init);
 343module_exit(rcuclassic_trace_cleanup);
 344
 345MODULE_AUTHOR("Paul E. McKenney");
 346MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
 347MODULE_LICENSE("GPL");
 348