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, you can access it online at 16 * http://www.gnu.org/licenses/gpl-2.0.html. 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 <linux/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 "tree.h" 48 49DECLARE_PER_CPU_SHARED_ALIGNED(unsigned long, rcu_qs_ctr); 50 51static int r_open(struct inode *inode, struct file *file, 52 const struct seq_operations *op) 53{ 54 int ret = seq_open(file, op); 55 if (!ret) { 56 struct seq_file *m = (struct seq_file *)file->private_data; 57 m->private = inode->i_private; 58 } 59 return ret; 60} 61 62static void *r_start(struct seq_file *m, loff_t *pos) 63{ 64 struct rcu_state *rsp = (struct rcu_state *)m->private; 65 *pos = cpumask_next(*pos - 1, cpu_possible_mask); 66 if ((*pos) < nr_cpu_ids) 67 return per_cpu_ptr(rsp->rda, *pos); 68 return NULL; 69} 70 71static void *r_next(struct seq_file *m, void *v, loff_t *pos) 72{ 73 (*pos)++; 74 return r_start(m, pos); 75} 76 77static void r_stop(struct seq_file *m, void *v) 78{ 79} 80 81static int show_rcubarrier(struct seq_file *m, void *v) 82{ 83 struct rcu_state *rsp = (struct rcu_state *)m->private; 84 seq_printf(m, "bcc: %d bseq: %lu\n", 85 atomic_read(&rsp->barrier_cpu_count), 86 rsp->barrier_sequence); 87 return 0; 88} 89 90static int rcubarrier_open(struct inode *inode, struct file *file) 91{ 92 return single_open(file, show_rcubarrier, inode->i_private); 93} 94 95static const struct file_operations rcubarrier_fops = { 96 .owner = THIS_MODULE, 97 .open = rcubarrier_open, 98 .read = seq_read, 99 .llseek = no_llseek, 100 .release = single_release, 101}; 102 103#ifdef CONFIG_RCU_BOOST 104 105static char convert_kthread_status(unsigned int kthread_status) 106{ 107 if (kthread_status > RCU_KTHREAD_MAX) 108 return '?'; 109 return "SRWOY"[kthread_status]; 110} 111 112#endif /* #ifdef CONFIG_RCU_BOOST */ 113 114static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) 115{ 116 long ql, qll; 117 118 if (!rdp->beenonline) 119 return; 120 seq_printf(m, "%3d%cc=%ld g=%ld cnq=%d/%d:%d", 121 rdp->cpu, 122 cpu_is_offline(rdp->cpu) ? '!' : ' ', 123 ulong2long(rdp->completed), ulong2long(rdp->gpnum), 124 rdp->cpu_no_qs.b.norm, 125 rdp->rcu_qs_ctr_snap == per_cpu(rcu_qs_ctr, rdp->cpu), 126 rdp->core_needs_qs); 127 seq_printf(m, " dt=%d/%llx/%d df=%lu", 128 atomic_read(&rdp->dynticks->dynticks), 129 rdp->dynticks->dynticks_nesting, 130 rdp->dynticks->dynticks_nmi_nesting, 131 rdp->dynticks_fqs); 132 seq_printf(m, " of=%lu", rdp->offline_fqs); 133 rcu_nocb_q_lengths(rdp, &ql, &qll); 134 qll += rdp->qlen_lazy; 135 ql += rdp->qlen; 136 seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c", 137 qll, ql, 138 ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != 139 rdp->nxttail[RCU_NEXT_TAIL]], 140 ".R"[rdp->nxttail[RCU_WAIT_TAIL] != 141 rdp->nxttail[RCU_NEXT_READY_TAIL]], 142 ".W"[rdp->nxttail[RCU_DONE_TAIL] != 143 rdp->nxttail[RCU_WAIT_TAIL]], 144 ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]); 145#ifdef CONFIG_RCU_BOOST 146 seq_printf(m, " kt=%d/%c ktl=%x", 147 per_cpu(rcu_cpu_has_work, rdp->cpu), 148 convert_kthread_status(per_cpu(rcu_cpu_kthread_status, 149 rdp->cpu)), 150 per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff); 151#endif /* #ifdef CONFIG_RCU_BOOST */ 152 seq_printf(m, " b=%ld", rdp->blimit); 153 seq_printf(m, " ci=%lu nci=%lu co=%lu ca=%lu\n", 154 rdp->n_cbs_invoked, rdp->n_nocbs_invoked, 155 rdp->n_cbs_orphaned, rdp->n_cbs_adopted); 156} 157 158static int show_rcudata(struct seq_file *m, void *v) 159{ 160 print_one_rcu_data(m, (struct rcu_data *)v); 161 return 0; 162} 163 164static const struct seq_operations rcudate_op = { 165 .start = r_start, 166 .next = r_next, 167 .stop = r_stop, 168 .show = show_rcudata, 169}; 170 171static int rcudata_open(struct inode *inode, struct file *file) 172{ 173 return r_open(inode, file, &rcudate_op); 174} 175 176static const struct file_operations rcudata_fops = { 177 .owner = THIS_MODULE, 178 .open = rcudata_open, 179 .read = seq_read, 180 .llseek = no_llseek, 181 .release = seq_release, 182}; 183 184static int show_rcuexp(struct seq_file *m, void *v) 185{ 186 struct rcu_state *rsp = (struct rcu_state *)m->private; 187 188 seq_printf(m, "s=%lu wd0=%lu wd1=%lu wd2=%lu wd3=%lu n=%lu enq=%d sc=%lu\n", 189 rsp->expedited_sequence, 190 atomic_long_read(&rsp->expedited_workdone0), 191 atomic_long_read(&rsp->expedited_workdone1), 192 atomic_long_read(&rsp->expedited_workdone2), 193 atomic_long_read(&rsp->expedited_workdone3), 194 atomic_long_read(&rsp->expedited_normal), 195 atomic_read(&rsp->expedited_need_qs), 196 rsp->expedited_sequence / 2); 197 return 0; 198} 199 200static int rcuexp_open(struct inode *inode, struct file *file) 201{ 202 return single_open(file, show_rcuexp, inode->i_private); 203} 204 205static const struct file_operations rcuexp_fops = { 206 .owner = THIS_MODULE, 207 .open = rcuexp_open, 208 .read = seq_read, 209 .llseek = no_llseek, 210 .release = single_release, 211}; 212 213#ifdef CONFIG_RCU_BOOST 214 215static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp) 216{ 217 seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ", 218 rnp->grplo, rnp->grphi, 219 "T."[list_empty(&rnp->blkd_tasks)], 220 "N."[!rnp->gp_tasks], 221 "E."[!rnp->exp_tasks], 222 "B."[!rnp->boost_tasks], 223 convert_kthread_status(rnp->boost_kthread_status), 224 rnp->n_tasks_boosted, rnp->n_exp_boosts, 225 rnp->n_normal_boosts); 226 seq_printf(m, "j=%04x bt=%04x\n", 227 (int)(jiffies & 0xffff), 228 (int)(rnp->boost_time & 0xffff)); 229 seq_printf(m, " balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n", 230 rnp->n_balk_blkd_tasks, 231 rnp->n_balk_exp_gp_tasks, 232 rnp->n_balk_boost_tasks, 233 rnp->n_balk_notblocked, 234 rnp->n_balk_notyet, 235 rnp->n_balk_nos); 236} 237 238static int show_rcu_node_boost(struct seq_file *m, void *unused) 239{ 240 struct rcu_node *rnp; 241 242 rcu_for_each_leaf_node(&rcu_preempt_state, rnp) 243 print_one_rcu_node_boost(m, rnp); 244 return 0; 245} 246 247static int rcu_node_boost_open(struct inode *inode, struct file *file) 248{ 249 return single_open(file, show_rcu_node_boost, NULL); 250} 251 252static const struct file_operations rcu_node_boost_fops = { 253 .owner = THIS_MODULE, 254 .open = rcu_node_boost_open, 255 .read = seq_read, 256 .llseek = no_llseek, 257 .release = single_release, 258}; 259 260#endif /* #ifdef CONFIG_RCU_BOOST */ 261 262static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) 263{ 264 unsigned long gpnum; 265 int level = 0; 266 struct rcu_node *rnp; 267 268 gpnum = rsp->gpnum; 269 seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x ", 270 ulong2long(rsp->completed), ulong2long(gpnum), 271 rsp->gp_state, 272 (long)(rsp->jiffies_force_qs - jiffies), 273 (int)(jiffies & 0xffff)); 274 seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n", 275 rsp->n_force_qs, rsp->n_force_qs_ngp, 276 rsp->n_force_qs - rsp->n_force_qs_ngp, 277 READ_ONCE(rsp->n_force_qs_lh), rsp->qlen_lazy, rsp->qlen); 278 for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) { 279 if (rnp->level != level) { 280 seq_puts(m, "\n"); 281 level = rnp->level; 282 } 283 seq_printf(m, "%lx/%lx->%lx %c%c>%c %d:%d ^%d ", 284 rnp->qsmask, rnp->qsmaskinit, rnp->qsmaskinitnext, 285 ".G"[rnp->gp_tasks != NULL], 286 ".E"[rnp->exp_tasks != NULL], 287 ".T"[!list_empty(&rnp->blkd_tasks)], 288 rnp->grplo, rnp->grphi, rnp->grpnum); 289 } 290 seq_puts(m, "\n"); 291} 292 293static int show_rcuhier(struct seq_file *m, void *v) 294{ 295 struct rcu_state *rsp = (struct rcu_state *)m->private; 296 print_one_rcu_state(m, rsp); 297 return 0; 298} 299 300static int rcuhier_open(struct inode *inode, struct file *file) 301{ 302 return single_open(file, show_rcuhier, inode->i_private); 303} 304 305static const struct file_operations rcuhier_fops = { 306 .owner = THIS_MODULE, 307 .open = rcuhier_open, 308 .read = seq_read, 309 .llseek = no_llseek, 310 .release = single_release, 311}; 312 313static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp) 314{ 315 unsigned long flags; 316 unsigned long completed; 317 unsigned long gpnum; 318 unsigned long gpage; 319 unsigned long gpmax; 320 struct rcu_node *rnp = &rsp->node[0]; 321 322 raw_spin_lock_irqsave(&rnp->lock, flags); 323 completed = READ_ONCE(rsp->completed); 324 gpnum = READ_ONCE(rsp->gpnum); 325 if (completed == gpnum) 326 gpage = 0; 327 else 328 gpage = jiffies - rsp->gp_start; 329 gpmax = rsp->gp_max; 330 raw_spin_unlock_irqrestore(&rnp->lock, flags); 331 seq_printf(m, "completed=%ld gpnum=%ld age=%ld max=%ld\n", 332 ulong2long(completed), ulong2long(gpnum), gpage, gpmax); 333} 334 335static int show_rcugp(struct seq_file *m, void *v) 336{ 337 struct rcu_state *rsp = (struct rcu_state *)m->private; 338 show_one_rcugp(m, rsp); 339 return 0; 340} 341 342static int rcugp_open(struct inode *inode, struct file *file) 343{ 344 return single_open(file, show_rcugp, inode->i_private); 345} 346 347static const struct file_operations rcugp_fops = { 348 .owner = THIS_MODULE, 349 .open = rcugp_open, 350 .read = seq_read, 351 .llseek = no_llseek, 352 .release = single_release, 353}; 354 355static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp) 356{ 357 if (!rdp->beenonline) 358 return; 359 seq_printf(m, "%3d%cnp=%ld ", 360 rdp->cpu, 361 cpu_is_offline(rdp->cpu) ? '!' : ' ', 362 rdp->n_rcu_pending); 363 seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ", 364 rdp->n_rp_core_needs_qs, 365 rdp->n_rp_report_qs, 366 rdp->n_rp_cb_ready, 367 rdp->n_rp_cpu_needs_gp); 368 seq_printf(m, "gpc=%ld gps=%ld nn=%ld ndw%ld\n", 369 rdp->n_rp_gp_completed, 370 rdp->n_rp_gp_started, 371 rdp->n_rp_nocb_defer_wakeup, 372 rdp->n_rp_need_nothing); 373} 374 375static int show_rcu_pending(struct seq_file *m, void *v) 376{ 377 print_one_rcu_pending(m, (struct rcu_data *)v); 378 return 0; 379} 380 381static const struct seq_operations rcu_pending_op = { 382 .start = r_start, 383 .next = r_next, 384 .stop = r_stop, 385 .show = show_rcu_pending, 386}; 387 388static int rcu_pending_open(struct inode *inode, struct file *file) 389{ 390 return r_open(inode, file, &rcu_pending_op); 391} 392 393static const struct file_operations rcu_pending_fops = { 394 .owner = THIS_MODULE, 395 .open = rcu_pending_open, 396 .read = seq_read, 397 .llseek = no_llseek, 398 .release = seq_release, 399}; 400 401static int show_rcutorture(struct seq_file *m, void *unused) 402{ 403 seq_printf(m, "rcutorture test sequence: %lu %s\n", 404 rcutorture_testseq >> 1, 405 (rcutorture_testseq & 0x1) ? "(test in progress)" : ""); 406 seq_printf(m, "rcutorture update version number: %lu\n", 407 rcutorture_vernum); 408 return 0; 409} 410 411static int rcutorture_open(struct inode *inode, struct file *file) 412{ 413 return single_open(file, show_rcutorture, NULL); 414} 415 416static const struct file_operations rcutorture_fops = { 417 .owner = THIS_MODULE, 418 .open = rcutorture_open, 419 .read = seq_read, 420 .llseek = seq_lseek, 421 .release = single_release, 422}; 423 424static struct dentry *rcudir; 425 426static int __init rcutree_trace_init(void) 427{ 428 struct rcu_state *rsp; 429 struct dentry *retval; 430 struct dentry *rspdir; 431 432 rcudir = debugfs_create_dir("rcu", NULL); 433 if (!rcudir) 434 goto free_out; 435 436 for_each_rcu_flavor(rsp) { 437 rspdir = debugfs_create_dir(rsp->name, rcudir); 438 if (!rspdir) 439 goto free_out; 440 441 retval = debugfs_create_file("rcudata", 0444, 442 rspdir, rsp, &rcudata_fops); 443 if (!retval) 444 goto free_out; 445 446 retval = debugfs_create_file("rcuexp", 0444, 447 rspdir, rsp, &rcuexp_fops); 448 if (!retval) 449 goto free_out; 450 451 retval = debugfs_create_file("rcu_pending", 0444, 452 rspdir, rsp, &rcu_pending_fops); 453 if (!retval) 454 goto free_out; 455 456 retval = debugfs_create_file("rcubarrier", 0444, 457 rspdir, rsp, &rcubarrier_fops); 458 if (!retval) 459 goto free_out; 460 461#ifdef CONFIG_RCU_BOOST 462 if (rsp == &rcu_preempt_state) { 463 retval = debugfs_create_file("rcuboost", 0444, 464 rspdir, NULL, &rcu_node_boost_fops); 465 if (!retval) 466 goto free_out; 467 } 468#endif 469 470 retval = debugfs_create_file("rcugp", 0444, 471 rspdir, rsp, &rcugp_fops); 472 if (!retval) 473 goto free_out; 474 475 retval = debugfs_create_file("rcuhier", 0444, 476 rspdir, rsp, &rcuhier_fops); 477 if (!retval) 478 goto free_out; 479 } 480 481 retval = debugfs_create_file("rcutorture", 0444, rcudir, 482 NULL, &rcutorture_fops); 483 if (!retval) 484 goto free_out; 485 return 0; 486free_out: 487 debugfs_remove_recursive(rcudir); 488 return 1; 489} 490 491static void __exit rcutree_trace_cleanup(void) 492{ 493 debugfs_remove_recursive(rcudir); 494} 495 496 497module_init(rcutree_trace_init); 498module_exit(rcutree_trace_cleanup); 499 500MODULE_AUTHOR("Paul E. McKenney"); 501MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation"); 502MODULE_LICENSE("GPL"); 503