kernel/rcutree_trace.c

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