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\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
  78 static 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
  91 static int rcudata_open(struct inode *inode, struct file *file)
  92 {
  93         return single_open(file, show_rcudata, NULL);
  94 }
  95
  96 static 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
 104 static 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
 125 static 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
 143 static int rcudata_csv_open(struct inode *inode, struct file *file)
 144 {
 145         return single_open(file, show_rcudata_csv, NULL);
 146 }
 147
 148 static 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
 156 static 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
 189 static 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
 202 static int rcuhier_open(struct inode *inode, struct file *file)
 203 {
 204         return single_open(file, show_rcuhier, NULL);
 205 }
 206
 207 static 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
 215 static 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
 228 static int rcugp_open(struct inode *inode, struct file *file)
 229 {
 230         return single_open(file, show_rcugp, NULL);
 231 }
 232
 233 static 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
 241 static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
 242 {
 243         seq_printf(m, "%3d%cnp=%ld "
 244                    "qsp=%ld cbr=%ld cng=%ld gpc=%ld gps=%ld nf=%ld nn=%ld\n",
 245                    rdp->cpu,
 246                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
 247                    rdp->n_rcu_pending,
 248                    rdp->n_rp_qs_pending,
 249                    rdp->n_rp_cb_ready,
 250                    rdp->n_rp_cpu_needs_gp,
 251                    rdp->n_rp_gp_completed,
 252                    rdp->n_rp_gp_started,
 253                    rdp->n_rp_need_fqs,
 254                    rdp->n_rp_need_nothing);
 255 }
 256
 257 static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
 258 {
 259         int cpu;
 260         struct rcu_data *rdp;
 261
 262         for_each_possible_cpu(cpu) {
 263                 rdp = rsp->rda[cpu];
 264                 if (rdp->beenonline)
 265                         print_one_rcu_pending(m, rdp);
 266         }
 267 }
 268
 269 static int show_rcu_pending(struct seq_file *m, void *unused)
 270 {
 271 #ifdef CONFIG_TREE_PREEMPT_RCU
 272         seq_puts(m, "rcu_preempt:\n");
 273         print_rcu_pendings(m, &rcu_preempt_state);
 274 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 275         seq_puts(m, "rcu_sched:\n");
 276         print_rcu_pendings(m, &rcu_sched_state);
 277         seq_puts(m, "rcu_bh:\n");
 278         print_rcu_pendings(m, &rcu_bh_state);
 279         return 0;
 280 }
 281
 282 static int rcu_pending_open(struct inode *inode, struct file *file)
 283 {
 284         return single_open(file, show_rcu_pending, NULL);
 285 }
 286
 287 static const struct file_operations rcu_pending_fops = {
 288         .owner = THIS_MODULE,
 289         .open = rcu_pending_open,
 290         .read = seq_read,
 291         .llseek = seq_lseek,
 292         .release = single_release,
 293 };
 294
 295 static struct dentry *rcudir;
 296
 297 static int __init rcuclassic_trace_init(void)
 298 {
 299         struct dentry *retval;
 300
 301         rcudir = debugfs_create_dir("rcu", NULL);
 302         if (!rcudir)
 303                 goto free_out;
 304
 305         retval = debugfs_create_file("rcudata", 0444, rcudir,
 306                                                 NULL, &rcudata_fops);
 307         if (!retval)
 308                 goto free_out;
 309
 310         retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
 311                                                 NULL, &rcudata_csv_fops);
 312         if (!retval)
 313                 goto free_out;
 314
 315         retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
 316         if (!retval)
 317                 goto free_out;
 318
 319         retval = debugfs_create_file("rcuhier", 0444, rcudir,
 320                                                 NULL, &rcuhier_fops);
 321         if (!retval)
 322                 goto free_out;
 323
 324         retval = debugfs_create_file("rcu_pending", 0444, rcudir,
 325                                                 NULL, &rcu_pending_fops);
 326         if (!retval)
 327                 goto free_out;
 328         return 0;
 329 free_out:
 330         debugfs_remove_recursive(rcudir);
 331         return 1;
 332 }
 333
 334 static void __exit rcuclassic_trace_cleanup(void)
 335 {
 336         debugfs_remove_recursive(rcudir);
 337 }
 338
 339
 340 module_init(rcuclassic_trace_init);
 341 module_exit(rcuclassic_trace_cleanup);
 342
 343 MODULE_AUTHOR("Paul E. McKenney");
 344 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
 345 MODULE_LICENSE("GPL");