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#include "rcutree.h"
  47
  48static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
  49{
  50        if (!rdp->beenonline)
  51                return;
  52        seq_printf(m, "%3d%cc=%ld g=%ld pq=%d pqc=%ld qp=%d",
  53                   rdp->cpu,
  54                   cpu_is_offline(rdp->cpu) ? '!' : ' ',
  55                   rdp->completed, rdp->gpnum,
  56                   rdp->passed_quiesc, rdp->passed_quiesc_completed,
  57                   rdp->qs_pending);
  58#ifdef CONFIG_NO_HZ
  59        seq_printf(m, " dt=%d/%d dn=%d df=%lu",
  60                   rdp->dynticks->dynticks,
  61                   rdp->dynticks->dynticks_nesting,
  62                   rdp->dynticks->dynticks_nmi,
  63                   rdp->dynticks_fqs);
  64#endif /* #ifdef CONFIG_NO_HZ */
  65        seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);
  66        seq_printf(m, " ql=%ld b=%ld\n", rdp->qlen, rdp->blimit);
  67}
  68
  69#define PRINT_RCU_DATA(name, func, m) \
  70        do { \
  71                int _p_r_d_i; \
  72                \
  73                for_each_possible_cpu(_p_r_d_i) \
  74                        func(m, &per_cpu(name, _p_r_d_i)); \
  75        } while (0)
  76
  77static int show_rcudata(struct seq_file *m, void *unused)
  78{
  79        seq_puts(m, "rcu:\n");
  80        PRINT_RCU_DATA(rcu_data, print_one_rcu_data, m);
  81        seq_puts(m, "rcu_bh:\n");
  82        PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
  83        return 0;
  84}
  85
  86static int rcudata_open(struct inode *inode, struct file *file)
  87{
  88        return single_open(file, show_rcudata, NULL);
  89}
  90
  91static struct file_operations rcudata_fops = {
  92        .owner = THIS_MODULE,
  93        .open = rcudata_open,
  94        .read = seq_read,
  95        .llseek = seq_lseek,
  96        .release = single_release,
  97};
  98
  99static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
 100{
 101        if (!rdp->beenonline)
 102                return;
 103        seq_printf(m, "%d,%s,%ld,%ld,%d,%ld,%d",
 104                   rdp->cpu,
 105                   cpu_is_offline(rdp->cpu) ? "\"Y\"" : "\"N\"",
 106                   rdp->completed, rdp->gpnum,
 107                   rdp->passed_quiesc, rdp->passed_quiesc_completed,
 108                   rdp->qs_pending);
 109#ifdef CONFIG_NO_HZ
 110        seq_printf(m, ",%d,%d,%d,%lu",
 111                   rdp->dynticks->dynticks,
 112                   rdp->dynticks->dynticks_nesting,
 113                   rdp->dynticks->dynticks_nmi,
 114                   rdp->dynticks_fqs);
 115#endif /* #ifdef CONFIG_NO_HZ */
 116        seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
 117        seq_printf(m, ",%ld,%ld\n", rdp->qlen, rdp->blimit);
 118}
 119
 120static int show_rcudata_csv(struct seq_file *m, void *unused)
 121{
 122        seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
 123#ifdef CONFIG_NO_HZ
 124        seq_puts(m, "\"dt\",\"dt nesting\",\"dn\",\"df\",");
 125#endif /* #ifdef CONFIG_NO_HZ */
 126        seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\"\n");
 127        seq_puts(m, "\"rcu:\"\n");
 128        PRINT_RCU_DATA(rcu_data, print_one_rcu_data_csv, m);
 129        seq_puts(m, "\"rcu_bh:\"\n");
 130        PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
 131        return 0;
 132}
 133
 134static int rcudata_csv_open(struct inode *inode, struct file *file)
 135{
 136        return single_open(file, show_rcudata_csv, NULL);
 137}
 138
 139static struct file_operations rcudata_csv_fops = {
 140        .owner = THIS_MODULE,
 141        .open = rcudata_csv_open,
 142        .read = seq_read,
 143        .llseek = seq_lseek,
 144        .release = single_release,
 145};
 146
 147static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
 148{
 149        int level = 0;
 150        struct rcu_node *rnp;
 151
 152        seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x "
 153                      "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
 154                   rsp->completed, rsp->gpnum, rsp->signaled,
 155                   (long)(rsp->jiffies_force_qs - jiffies),
 156                   (int)(jiffies & 0xffff),
 157                   rsp->n_force_qs, rsp->n_force_qs_ngp,
 158                   rsp->n_force_qs - rsp->n_force_qs_ngp,
 159                   rsp->n_force_qs_lh);
 160        for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
 161                if (rnp->level != level) {
 162                        seq_puts(m, "\n");
 163                        level = rnp->level;
 164                }
 165                seq_printf(m, "%lx/%lx %d:%d ^%d    ",
 166                           rnp->qsmask, rnp->qsmaskinit,
 167                           rnp->grplo, rnp->grphi, rnp->grpnum);
 168        }
 169        seq_puts(m, "\n");
 170}
 171
 172static int show_rcuhier(struct seq_file *m, void *unused)
 173{
 174        seq_puts(m, "rcu:\n");
 175        print_one_rcu_state(m, &rcu_state);
 176        seq_puts(m, "rcu_bh:\n");
 177        print_one_rcu_state(m, &rcu_bh_state);
 178        return 0;
 179}
 180
 181static int rcuhier_open(struct inode *inode, struct file *file)
 182{
 183        return single_open(file, show_rcuhier, NULL);
 184}
 185
 186static struct file_operations rcuhier_fops = {
 187        .owner = THIS_MODULE,
 188        .open = rcuhier_open,
 189        .read = seq_read,
 190        .llseek = seq_lseek,
 191        .release = single_release,
 192};
 193
 194static int show_rcugp(struct seq_file *m, void *unused)
 195{
 196        seq_printf(m, "rcu: completed=%ld  gpnum=%ld\n",
 197                   rcu_state.completed, rcu_state.gpnum);
 198        seq_printf(m, "rcu_bh: completed=%ld  gpnum=%ld\n",
 199                   rcu_bh_state.completed, rcu_bh_state.gpnum);
 200        return 0;
 201}
 202
 203static int rcugp_open(struct inode *inode, struct file *file)
 204{
 205        return single_open(file, show_rcugp, NULL);
 206}
 207
 208static struct file_operations rcugp_fops = {
 209        .owner = THIS_MODULE,
 210        .open = rcugp_open,
 211        .read = seq_read,
 212        .llseek = seq_lseek,
 213        .release = single_release,
 214};
 215
 216static struct dentry *rcudir, *datadir, *datadir_csv, *hierdir, *gpdir;
 217static int __init rcuclassic_trace_init(void)
 218{
 219        rcudir = debugfs_create_dir("rcu", NULL);
 220        if (!rcudir)
 221                goto out;
 222
 223        datadir = debugfs_create_file("rcudata", 0444, rcudir,
 224                                                NULL, &rcudata_fops);
 225        if (!datadir)
 226                goto free_out;
 227
 228        datadir_csv = debugfs_create_file("rcudata.csv", 0444, rcudir,
 229                                                NULL, &rcudata_csv_fops);
 230        if (!datadir_csv)
 231                goto free_out;
 232
 233        gpdir = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
 234        if (!gpdir)
 235                goto free_out;
 236
 237        hierdir = debugfs_create_file("rcuhier", 0444, rcudir,
 238                                                NULL, &rcuhier_fops);
 239        if (!hierdir)
 240                goto free_out;
 241        return 0;
 242free_out:
 243        if (datadir)
 244                debugfs_remove(datadir);
 245        if (datadir_csv)
 246                debugfs_remove(datadir_csv);
 247        if (gpdir)
 248                debugfs_remove(gpdir);
 249        debugfs_remove(rcudir);
 250out:
 251        return 1;
 252}
 253
 254static void __exit rcuclassic_trace_cleanup(void)
 255{
 256        debugfs_remove(datadir);
 257        debugfs_remove(datadir_csv);
 258        debugfs_remove(gpdir);
 259        debugfs_remove(hierdir);
 260        debugfs_remove(rcudir);
 261}
 262
 263
 264module_init(rcuclassic_trace_init);
 265module_exit(rcuclassic_trace_cleanup);
 266
 267MODULE_AUTHOR("Paul E. McKenney");
 268MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
 269MODULE_LICENSE("GPL");
 270