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=%ld g=%ld pq=%d pqc=%ld 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,%ld,%ld,%d,%ld,%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        int level = 0;
 159        struct rcu_node *rnp;
 160
 161        seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x "
 162                      "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld\n",
 163                   rsp->completed, rsp->gpnum, rsp->signaled,
 164                   (long)(rsp->jiffies_force_qs - jiffies),
 165                   (int)(jiffies & 0xffff),
 166                   rsp->n_force_qs, rsp->n_force_qs_ngp,
 167                   rsp->n_force_qs - rsp->n_force_qs_ngp,
 168                   rsp->n_force_qs_lh, rsp->orphan_qlen);
 169        for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
 170                if (rnp->level != level) {
 171                        seq_puts(m, "\n");
 172                        level = rnp->level;
 173                }
 174                seq_printf(m, "%lx/%lx %d:%d ^%d    ",
 175                           rnp->qsmask, rnp->qsmaskinit,
 176                           rnp->grplo, rnp->grphi, rnp->grpnum);
 177        }
 178        seq_puts(m, "\n");
 179}
 180
 181static int show_rcuhier(struct seq_file *m, void *unused)
 182{
 183#ifdef CONFIG_TREE_PREEMPT_RCU
 184        seq_puts(m, "rcu_preempt:\n");
 185        print_one_rcu_state(m, &rcu_preempt_state);
 186#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 187        seq_puts(m, "rcu_sched:\n");
 188        print_one_rcu_state(m, &rcu_sched_state);
 189        seq_puts(m, "rcu_bh:\n");
 190        print_one_rcu_state(m, &rcu_bh_state);
 191        return 0;
 192}
 193
 194static int rcuhier_open(struct inode *inode, struct file *file)
 195{
 196        return single_open(file, show_rcuhier, NULL);
 197}
 198
 199static const struct file_operations rcuhier_fops = {
 200        .owner = THIS_MODULE,
 201        .open = rcuhier_open,
 202        .read = seq_read,
 203        .llseek = seq_lseek,
 204        .release = single_release,
 205};
 206
 207static int show_rcugp(struct seq_file *m, void *unused)
 208{
 209#ifdef CONFIG_TREE_PREEMPT_RCU
 210        seq_printf(m, "rcu_preempt: completed=%ld  gpnum=%ld\n",
 211                   rcu_preempt_state.completed, rcu_preempt_state.gpnum);
 212#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 213        seq_printf(m, "rcu_sched: completed=%ld  gpnum=%ld\n",
 214                   rcu_sched_state.completed, rcu_sched_state.gpnum);
 215        seq_printf(m, "rcu_bh: completed=%ld  gpnum=%ld\n",
 216                   rcu_bh_state.completed, rcu_bh_state.gpnum);
 217        return 0;
 218}
 219
 220static int rcugp_open(struct inode *inode, struct file *file)
 221{
 222        return single_open(file, show_rcugp, NULL);
 223}
 224
 225static const struct file_operations rcugp_fops = {
 226        .owner = THIS_MODULE,
 227        .open = rcugp_open,
 228        .read = seq_read,
 229        .llseek = seq_lseek,
 230        .release = single_release,
 231};
 232
 233static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
 234{
 235        seq_printf(m, "%3d%cnp=%ld "
 236                   "qsp=%ld cbr=%ld cng=%ld gpc=%ld gps=%ld nf=%ld nn=%ld\n",
 237                   rdp->cpu,
 238                   cpu_is_offline(rdp->cpu) ? '!' : ' ',
 239                   rdp->n_rcu_pending,
 240                   rdp->n_rp_qs_pending,
 241                   rdp->n_rp_cb_ready,
 242                   rdp->n_rp_cpu_needs_gp,
 243                   rdp->n_rp_gp_completed,
 244                   rdp->n_rp_gp_started,
 245                   rdp->n_rp_need_fqs,
 246                   rdp->n_rp_need_nothing);
 247}
 248
 249static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
 250{
 251        int cpu;
 252        struct rcu_data *rdp;
 253
 254        for_each_possible_cpu(cpu) {
 255                rdp = rsp->rda[cpu];
 256                if (rdp->beenonline)
 257                        print_one_rcu_pending(m, rdp);
 258        }
 259}
 260
 261static int show_rcu_pending(struct seq_file *m, void *unused)
 262{
 263#ifdef CONFIG_TREE_PREEMPT_RCU
 264        seq_puts(m, "rcu_preempt:\n");
 265        print_rcu_pendings(m, &rcu_preempt_state);
 266#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 267        seq_puts(m, "rcu_sched:\n");
 268        print_rcu_pendings(m, &rcu_sched_state);
 269        seq_puts(m, "rcu_bh:\n");
 270        print_rcu_pendings(m, &rcu_bh_state);
 271        return 0;
 272}
 273
 274static int rcu_pending_open(struct inode *inode, struct file *file)
 275{
 276        return single_open(file, show_rcu_pending, NULL);
 277}
 278
 279static const struct file_operations rcu_pending_fops = {
 280        .owner = THIS_MODULE,
 281        .open = rcu_pending_open,
 282        .read = seq_read,
 283        .llseek = seq_lseek,
 284        .release = single_release,
 285};
 286
 287static struct dentry *rcudir;
 288
 289static int __init rcuclassic_trace_init(void)
 290{
 291        struct dentry *retval;
 292
 293        rcudir = debugfs_create_dir("rcu", NULL);
 294        if (!rcudir)
 295                goto free_out;
 296
 297        retval = debugfs_create_file("rcudata", 0444, rcudir,
 298                                                NULL, &rcudata_fops);
 299        if (!retval)
 300                goto free_out;
 301
 302        retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
 303                                                NULL, &rcudata_csv_fops);
 304        if (!retval)
 305                goto free_out;
 306
 307        retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
 308        if (!retval)
 309                goto free_out;
 310
 311        retval = debugfs_create_file("rcuhier", 0444, rcudir,
 312                                                NULL, &rcuhier_fops);
 313        if (!retval)
 314                goto free_out;
 315
 316        retval = debugfs_create_file("rcu_pending", 0444, rcudir,
 317                                                NULL, &rcu_pending_fops);
 318        if (!retval)
 319                goto free_out;
 320        return 0;
 321free_out:
 322        debugfs_remove_recursive(rcudir);
 323        return 1;
 324}
 325
 326static void __exit rcuclassic_trace_cleanup(void)
 327{
 328        debugfs_remove_recursive(rcudir);
 329}
 330
 331
 332module_init(rcuclassic_trace_init);
 333module_exit(rcuclassic_trace_cleanup);
 334
 335MODULE_AUTHOR("Paul E. McKenney");
 336MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
 337MODULE_LICENSE("GPL");
 338