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/%d df=%lu",
  61                    atomic_read(&rdp->dynticks->dynticks),
  62                    rdp->dynticks->dynticks_nesting,
  63                    rdp->dynticks->dynticks_nmi_nesting,
  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 qs=%c%c%c%c b=%ld",
  68                    rdp->qlen,
  69                    ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
  70                         rdp->nxttail[RCU_NEXT_TAIL]],
  71                    ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
  72                         rdp->nxttail[RCU_NEXT_READY_TAIL]],
  73                    ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
  74                         rdp->nxttail[RCU_WAIT_TAIL]],
  75                    ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],
  76                    rdp->blimit);
  77         seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
  78                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
  79 }
  80
  81 #define PRINT_RCU_DATA(name, func, m) \
  82         do { \
  83                 int _p_r_d_i; \
  84                 \
  85                 for_each_possible_cpu(_p_r_d_i) \
  86                         func(m, &per_cpu(name, _p_r_d_i)); \
  87         } while (0)
  88
  89 static int show_rcudata(struct seq_file *m, void *unused)
  90 {
  91 #ifdef CONFIG_TREE_PREEMPT_RCU
  92         seq_puts(m, "rcu_preempt:\n");
  93         PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data, m);
  94 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
  95         seq_puts(m, "rcu_sched:\n");
  96         PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data, m);
  97         seq_puts(m, "rcu_bh:\n");
  98         PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
  99         return 0;
 100 }
 101
 102 static int rcudata_open(struct inode *inode, struct file *file)
 103 {
 104         return single_open(file, show_rcudata, NULL);
 105 }
 106
 107 static const struct file_operations rcudata_fops = {
 108         .owner = THIS_MODULE,
 109         .open = rcudata_open,
 110         .read = seq_read,
 111         .llseek = seq_lseek,
 112         .release = single_release,
 113 };
 114
 115 static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
 116 {
 117         if (!rdp->beenonline)
 118                 return;
 119         seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
 120                    rdp->cpu,
 121                    cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
 122                    rdp->completed, rdp->gpnum,
 123                    rdp->passed_quiesc, rdp->passed_quiesc_completed,
 124                    rdp->qs_pending);
 125 #ifdef CONFIG_NO_HZ
 126         seq_printf(m, ",%d,%d,%d,%lu",
 127                    atomic_read(&rdp->dynticks->dynticks),
 128                    rdp->dynticks->dynticks_nesting,
 129                    rdp->dynticks->dynticks_nmi_nesting,
 130                    rdp->dynticks_fqs);
 131 #endif /* #ifdef CONFIG_NO_HZ */
 132         seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
 133         seq_printf(m, ",%ld,\"%c%c%c%c\",%ld", rdp->qlen,
 134                    ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
 135                         rdp->nxttail[RCU_NEXT_TAIL]],
 136                    ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
 137                         rdp->nxttail[RCU_NEXT_READY_TAIL]],
 138                    ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
 139                         rdp->nxttail[RCU_WAIT_TAIL]],
 140                    ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],
 141                    rdp->blimit);
 142         seq_printf(m, ",%lu,%lu,%lu\n",
 143                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
 144 }
 145
 146 static int show_rcudata_csv(struct seq_file *m, void *unused)
 147 {
 148         seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
 149 #ifdef CONFIG_NO_HZ
 150         seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");
 151 #endif /* #ifdef CONFIG_NO_HZ */
 152         seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\",\"ci\",\"co\",\"ca\"\n");
 153 #ifdef CONFIG_TREE_PREEMPT_RCU
 154         seq_puts(m, "\"rcu_preempt:\"\n");
 155         PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data_csv, m);
 156 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 157         seq_puts(m, "\"rcu_sched:\"\n");
 158         PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data_csv, m);
 159         seq_puts(m, "\"rcu_bh:\"\n");
 160         PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
 161         return 0;
 162 }
 163
 164 static int rcudata_csv_open(struct inode *inode, struct file *file)
 165 {
 166         return single_open(file, show_rcudata_csv, NULL);
 167 }
 168
 169 static const struct file_operations rcudata_csv_fops = {
 170         .owner = THIS_MODULE,
 171         .open = rcudata_csv_open,
 172         .read = seq_read,
 173         .llseek = seq_lseek,
 174         .release = single_release,
 175 };
 176
 177 #ifdef CONFIG_RCU_BOOST
 178
 179 static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
 180 {
 181         seq_printf(m,  "%d:%d tasks=%c%c%c%c ntb=%lu neb=%lu nnb=%lu "
 182                    "j=%04x bt=%04x\n",
 183                    rnp->grplo, rnp->grphi,
 184                    "T."[list_empty(&rnp->blkd_tasks)],
 185                    "N."[!rnp->gp_tasks],
 186                    "E."[!rnp->exp_tasks],
 187                    "B."[!rnp->boost_tasks],
 188                    rnp->n_tasks_boosted, rnp->n_exp_boosts,
 189                    rnp->n_normal_boosts,
 190                    (int)(jiffies & 0xffff),
 191                    (int)(rnp->boost_time & 0xffff));
 192         seq_printf(m, "%s: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
 193                    "     balk",
 194                    rnp->n_balk_blkd_tasks,
 195                    rnp->n_balk_exp_gp_tasks,
 196                    rnp->n_balk_boost_tasks,
 197                    rnp->n_balk_notblocked,
 198                    rnp->n_balk_notyet,
 199                    rnp->n_balk_nos);
 200 }
 201
 202 static int show_rcu_node_boost(struct seq_file *m, void *unused)
 203 {
 204         struct rcu_node *rnp;
 205
 206         rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
 207                 print_one_rcu_node_boost(m, rnp);
 208         return 0;
 209 }
 210
 211 static int rcu_node_boost_open(struct inode *inode, struct file *file)
 212 {
 213         return single_open(file, show_rcu_node_boost, NULL);
 214 }
 215
 216 static const struct file_operations rcu_node_boost_fops = {
 217         .owner = THIS_MODULE,
 218         .open = rcu_node_boost_open,
 219         .read = seq_read,
 220         .llseek = seq_lseek,
 221         .release = single_release,
 222 };
 223
 224 /*
 225  * Create the rcuboost debugfs entry.  Standard error return.
 226  */
 227 static int rcu_boost_trace_create_file(struct dentry *rcudir)
 228 {
 229         return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
 230                                     &rcu_node_boost_fops);
 231 }
 232
 233 #else /* #ifdef CONFIG_RCU_BOOST */
 234
 235 static int rcu_boost_trace_create_file(struct dentry *rcudir)
 236 {
 237         return 0;  /* There cannot be an error if we didn't create it! */
 238 }
 239
 240 #endif /* #else #ifdef CONFIG_RCU_BOOST */
 241
 242 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
 243 {
 244         unsigned long gpnum;
 245         int level = 0;
 246         struct rcu_node *rnp;
 247
 248         gpnum = rsp->gpnum;
 249         seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "
 250                       "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
 251                    rsp->completed, gpnum, rsp->signaled,
 252                    (long)(rsp->jiffies_force_qs - jiffies),
 253                    (int)(jiffies & 0xffff),
 254                    rsp->n_force_qs, rsp->n_force_qs_ngp,
 255                    rsp->n_force_qs - rsp->n_force_qs_ngp,
 256                    rsp->n_force_qs_lh);
 257         for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
 258                 if (rnp->level != level) {
 259                         seq_puts(m, "\n");
 260                         level = rnp->level;
 261                 }
 262                 seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d    ",
 263                            rnp->qsmask, rnp->qsmaskinit,
 264                            ".G"[rnp->gp_tasks != NULL],
 265                            ".E"[rnp->exp_tasks != NULL],
 266                            ".T"[!list_empty(&rnp->blkd_tasks)],
 267                            rnp->grplo, rnp->grphi, rnp->grpnum);
 268         }
 269         seq_puts(m, "\n");
 270 }
 271
 272 static int show_rcuhier(struct seq_file *m, void *unused)
 273 {
 274 #ifdef CONFIG_TREE_PREEMPT_RCU
 275         seq_puts(m, "rcu_preempt:\n");
 276         print_one_rcu_state(m, &rcu_preempt_state);
 277 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 278         seq_puts(m, "rcu_sched:\n");
 279         print_one_rcu_state(m, &rcu_sched_state);
 280         seq_puts(m, "rcu_bh:\n");
 281         print_one_rcu_state(m, &rcu_bh_state);
 282         return 0;
 283 }
 284
 285 static int rcuhier_open(struct inode *inode, struct file *file)
 286 {
 287         return single_open(file, show_rcuhier, NULL);
 288 }
 289
 290 static const struct file_operations rcuhier_fops = {
 291         .owner = THIS_MODULE,
 292         .open = rcuhier_open,
 293         .read = seq_read,
 294         .llseek = seq_lseek,
 295         .release = single_release,
 296 };
 297
 298 static int show_rcugp(struct seq_file *m, void *unused)
 299 {
 300 #ifdef CONFIG_TREE_PREEMPT_RCU
 301         seq_printf(m, "rcu_preempt: completed=%ld  gpnum=%lu\n",
 302                    rcu_preempt_state.completed, rcu_preempt_state.gpnum);
 303 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 304         seq_printf(m, "rcu_sched: completed=%ld  gpnum=%lu\n",
 305                    rcu_sched_state.completed, rcu_sched_state.gpnum);
 306         seq_printf(m, "rcu_bh: completed=%ld  gpnum=%lu\n",
 307                    rcu_bh_state.completed, rcu_bh_state.gpnum);
 308         return 0;
 309 }
 310
 311 static int rcugp_open(struct inode *inode, struct file *file)
 312 {
 313         return single_open(file, show_rcugp, NULL);
 314 }
 315
 316 static const struct file_operations rcugp_fops = {
 317         .owner = THIS_MODULE,
 318         .open = rcugp_open,
 319         .read = seq_read,
 320         .llseek = seq_lseek,
 321         .release = single_release,
 322 };
 323
 324 static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
 325 {
 326         seq_printf(m, "%3d%cnp=%ld "
 327                    "qsp=%ld rpq=%ld cbr=%ld cng=%ld "
 328                    "gpc=%ld gps=%ld nf=%ld nn=%ld\n",
 329                    rdp->cpu,
 330                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
 331                    rdp->n_rcu_pending,
 332                    rdp->n_rp_qs_pending,
 333                    rdp->n_rp_report_qs,
 334                    rdp->n_rp_cb_ready,
 335                    rdp->n_rp_cpu_needs_gp,
 336                    rdp->n_rp_gp_completed,
 337                    rdp->n_rp_gp_started,
 338                    rdp->n_rp_need_fqs,
 339                    rdp->n_rp_need_nothing);
 340 }
 341
 342 static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
 343 {
 344         int cpu;
 345         struct rcu_data *rdp;
 346
 347         for_each_possible_cpu(cpu) {
 348                 rdp = per_cpu_ptr(rsp->rda, cpu);
 349                 if (rdp->beenonline)
 350                         print_one_rcu_pending(m, rdp);
 351         }
 352 }
 353
 354 static int show_rcu_pending(struct seq_file *m, void *unused)
 355 {
 356 #ifdef CONFIG_TREE_PREEMPT_RCU
 357         seq_puts(m, "rcu_preempt:\n");
 358         print_rcu_pendings(m, &rcu_preempt_state);
 359 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 360         seq_puts(m, "rcu_sched:\n");
 361         print_rcu_pendings(m, &rcu_sched_state);
 362         seq_puts(m, "rcu_bh:\n");
 363         print_rcu_pendings(m, &rcu_bh_state);
 364         return 0;
 365 }
 366
 367 static int rcu_pending_open(struct inode *inode, struct file *file)
 368 {
 369         return single_open(file, show_rcu_pending, NULL);
 370 }
 371
 372 static const struct file_operations rcu_pending_fops = {
 373         .owner = THIS_MODULE,
 374         .open = rcu_pending_open,
 375         .read = seq_read,
 376         .llseek = seq_lseek,
 377         .release = single_release,
 378 };
 379
 380 static struct dentry *rcudir;
 381
 382 static int __init rcutree_trace_init(void)
 383 {
 384         struct dentry *retval;
 385
 386         rcudir = debugfs_create_dir("rcu", NULL);
 387         if (!rcudir)
 388                 goto free_out;
 389
 390         retval = debugfs_create_file("rcudata", 0444, rcudir,
 391                                                 NULL, &rcudata_fops);
 392         if (!retval)
 393                 goto free_out;
 394
 395         retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
 396                                                 NULL, &rcudata_csv_fops);
 397         if (!retval)
 398                 goto free_out;
 399
 400         if (rcu_boost_trace_create_file(rcudir))
 401                 goto free_out;
 402
 403         retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
 404         if (!retval)
 405                 goto free_out;
 406
 407         retval = debugfs_create_file("rcuhier", 0444, rcudir,
 408                                                 NULL, &rcuhier_fops);
 409         if (!retval)
 410                 goto free_out;
 411
 412         retval = debugfs_create_file("rcu_pending", 0444, rcudir,
 413                                                 NULL, &rcu_pending_fops);
 414         if (!retval)
 415                 goto free_out;
 416         return 0;
 417 free_out:
 418         debugfs_remove_recursive(rcudir);
 419         return 1;
 420 }
 421
 422 static void __exit rcutree_trace_cleanup(void)
 423 {
 424         debugfs_remove_recursive(rcudir);
 425 }
 426
 427
 428 module_init(rcutree_trace_init);
 429 module_exit(rcutree_trace_cleanup);
 430
 431 MODULE_AUTHOR("Paul E. McKenney");
 432 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
 433 MODULE_LICENSE("GPL");