| 1 | /* |
| 2 | * Read-Copy Update tracing for hierarchical 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 | * Author: Paul E. McKenney |
| 20 | * |
| 21 | * Papers: http://www.rdrop.com/users/paulmck/RCU |
| 22 | * |
| 23 | * For detailed explanation of Read-Copy Update mechanism see - |
| 24 | * Documentation/RCU |
| 25 | * |
| 26 | */ |
| 27 | #include <linux/types.h> |
| 28 | #include <linux/kernel.h> |
| 29 | #include <linux/init.h> |
| 30 | #include <linux/spinlock.h> |
| 31 | #include <linux/smp.h> |
| 32 | #include <linux/rcupdate.h> |
| 33 | #include <linux/interrupt.h> |
| 34 | #include <linux/sched.h> |
| 35 | #include <linux/atomic.h> |
| 36 | #include <linux/bitops.h> |
| 37 | #include <linux/completion.h> |
| 38 | #include <linux/percpu.h> |
| 39 | #include <linux/notifier.h> |
| 40 | #include <linux/cpu.h> |
| 41 | #include <linux/mutex.h> |
| 42 | #include <linux/debugfs.h> |
| 43 | #include <linux/seq_file.h> |
| 44 | |
| 45 | #define RCU_TREE_NONCORE |
| 46 | #include "tree.h" |
| 47 | |
| 48 | DECLARE_PER_CPU_SHARED_ALIGNED(unsigned long, rcu_qs_ctr); |
| 49 | |
| 50 | static int r_open(struct inode *inode, struct file *file, |
| 51 | const struct seq_operations *op) |
| 52 | { |
| 53 | int ret = seq_open(file, op); |
| 54 | if (!ret) { |
| 55 | struct seq_file *m = (struct seq_file *)file->private_data; |
| 56 | m->private = inode->i_private; |
| 57 | } |
| 58 | return ret; |
| 59 | } |
| 60 | |
| 61 | static void *r_start(struct seq_file *m, loff_t *pos) |
| 62 | { |
| 63 | struct rcu_state *rsp = (struct rcu_state *)m->private; |
| 64 | *pos = cpumask_next(*pos - 1, cpu_possible_mask); |
| 65 | if ((*pos) < nr_cpu_ids) |
| 66 | return per_cpu_ptr(rsp->rda, *pos); |
| 67 | return NULL; |
| 68 | } |
| 69 | |
| 70 | static void *r_next(struct seq_file *m, void *v, loff_t *pos) |
| 71 | { |
| 72 | (*pos)++; |
| 73 | return r_start(m, pos); |
| 74 | } |
| 75 | |
| 76 | static void r_stop(struct seq_file *m, void *v) |
| 77 | { |
| 78 | } |
| 79 | |
| 80 | static int show_rcubarrier(struct seq_file *m, void *v) |
| 81 | { |
| 82 | struct rcu_state *rsp = (struct rcu_state *)m->private; |
| 83 | seq_printf(m, "bcc: %d bseq: %lu\n", |
| 84 | atomic_read(&rsp->barrier_cpu_count), |
| 85 | rsp->barrier_sequence); |
| 86 | return 0; |
| 87 | } |
| 88 | |
| 89 | static int rcubarrier_open(struct inode *inode, struct file *file) |
| 90 | { |
| 91 | return single_open(file, show_rcubarrier, inode->i_private); |
| 92 | } |
| 93 | |
| 94 | static const struct file_operations rcubarrier_fops = { |
| 95 | .owner = THIS_MODULE, |
| 96 | .open = rcubarrier_open, |
| 97 | .read = seq_read, |
| 98 | .llseek = no_llseek, |
| 99 | .release = single_release, |
| 100 | }; |
| 101 | |
| 102 | #ifdef CONFIG_RCU_BOOST |
| 103 | |
| 104 | static char convert_kthread_status(unsigned int kthread_status) |
| 105 | { |
| 106 | if (kthread_status > RCU_KTHREAD_MAX) |
| 107 | return '?'; |
| 108 | return "SRWOY"[kthread_status]; |
| 109 | } |
| 110 | |
| 111 | #endif /* #ifdef CONFIG_RCU_BOOST */ |
| 112 | |
| 113 | static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) |
| 114 | { |
| 115 | long ql, qll; |
| 116 | |
| 117 | if (!rdp->beenonline) |
| 118 | return; |
| 119 | seq_printf(m, "%3d%cc=%ld g=%ld cnq=%d/%d:%d", |
| 120 | rdp->cpu, |
| 121 | cpu_is_offline(rdp->cpu) ? '!' : ' ', |
| 122 | ulong2long(rdp->completed), ulong2long(rdp->gpnum), |
| 123 | rdp->cpu_no_qs.b.norm, |
| 124 | rdp->rcu_qs_ctr_snap == per_cpu(rcu_qs_ctr, rdp->cpu), |
| 125 | rdp->core_needs_qs); |
| 126 | seq_printf(m, " dt=%d/%llx/%d df=%lu", |
| 127 | atomic_read(&rdp->dynticks->dynticks), |
| 128 | rdp->dynticks->dynticks_nesting, |
| 129 | rdp->dynticks->dynticks_nmi_nesting, |
| 130 | rdp->dynticks_fqs); |
| 131 | seq_printf(m, " of=%lu", rdp->offline_fqs); |
| 132 | rcu_nocb_q_lengths(rdp, &ql, &qll); |
| 133 | qll += rdp->qlen_lazy; |
| 134 | ql += rdp->qlen; |
| 135 | seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c", |
| 136 | qll, ql, |
| 137 | ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] != |
| 138 | rdp->nxttail[RCU_NEXT_TAIL]], |
| 139 | ".R"[rdp->nxttail[RCU_WAIT_TAIL] != |
| 140 | rdp->nxttail[RCU_NEXT_READY_TAIL]], |
| 141 | ".W"[rdp->nxttail[RCU_DONE_TAIL] != |
| 142 | rdp->nxttail[RCU_WAIT_TAIL]], |
| 143 | ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]); |
| 144 | #ifdef CONFIG_RCU_BOOST |
| 145 | seq_printf(m, " kt=%d/%c ktl=%x", |
| 146 | per_cpu(rcu_cpu_has_work, rdp->cpu), |
| 147 | convert_kthread_status(per_cpu(rcu_cpu_kthread_status, |
| 148 | rdp->cpu)), |
| 149 | per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff); |
| 150 | #endif /* #ifdef CONFIG_RCU_BOOST */ |
| 151 | seq_printf(m, " b=%ld", rdp->blimit); |
| 152 | seq_printf(m, " ci=%lu nci=%lu co=%lu ca=%lu\n", |
| 153 | rdp->n_cbs_invoked, rdp->n_nocbs_invoked, |
| 154 | rdp->n_cbs_orphaned, rdp->n_cbs_adopted); |
| 155 | } |
| 156 | |
| 157 | static int show_rcudata(struct seq_file *m, void *v) |
| 158 | { |
| 159 | print_one_rcu_data(m, (struct rcu_data *)v); |
| 160 | return 0; |
| 161 | } |
| 162 | |
| 163 | static const struct seq_operations rcudate_op = { |
| 164 | .start = r_start, |
| 165 | .next = r_next, |
| 166 | .stop = r_stop, |
| 167 | .show = show_rcudata, |
| 168 | }; |
| 169 | |
| 170 | static int rcudata_open(struct inode *inode, struct file *file) |
| 171 | { |
| 172 | return r_open(inode, file, &rcudate_op); |
| 173 | } |
| 174 | |
| 175 | static const struct file_operations rcudata_fops = { |
| 176 | .owner = THIS_MODULE, |
| 177 | .open = rcudata_open, |
| 178 | .read = seq_read, |
| 179 | .llseek = no_llseek, |
| 180 | .release = seq_release, |
| 181 | }; |
| 182 | |
| 183 | static int show_rcuexp(struct seq_file *m, void *v) |
| 184 | { |
| 185 | int cpu; |
| 186 | struct rcu_state *rsp = (struct rcu_state *)m->private; |
| 187 | struct rcu_data *rdp; |
| 188 | unsigned long s1 = 0, s2 = 0, s3 = 0; |
| 189 | |
| 190 | for_each_possible_cpu(cpu) { |
| 191 | rdp = per_cpu_ptr(rsp->rda, cpu); |
| 192 | s1 += atomic_long_read(&rdp->exp_workdone1); |
| 193 | s2 += atomic_long_read(&rdp->exp_workdone2); |
| 194 | s3 += atomic_long_read(&rdp->exp_workdone3); |
| 195 | } |
| 196 | seq_printf(m, "s=%lu wd1=%lu wd2=%lu wd3=%lu n=%lu enq=%d sc=%lu\n", |
| 197 | rsp->expedited_sequence, s1, s2, s3, |
| 198 | atomic_long_read(&rsp->expedited_normal), |
| 199 | atomic_read(&rsp->expedited_need_qs), |
| 200 | rsp->expedited_sequence / 2); |
| 201 | return 0; |
| 202 | } |
| 203 | |
| 204 | static int rcuexp_open(struct inode *inode, struct file *file) |
| 205 | { |
| 206 | return single_open(file, show_rcuexp, inode->i_private); |
| 207 | } |
| 208 | |
| 209 | static const struct file_operations rcuexp_fops = { |
| 210 | .owner = THIS_MODULE, |
| 211 | .open = rcuexp_open, |
| 212 | .read = seq_read, |
| 213 | .llseek = no_llseek, |
| 214 | .release = single_release, |
| 215 | }; |
| 216 | |
| 217 | #ifdef CONFIG_RCU_BOOST |
| 218 | |
| 219 | static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp) |
| 220 | { |
| 221 | seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ", |
| 222 | rnp->grplo, rnp->grphi, |
| 223 | "T."[list_empty(&rnp->blkd_tasks)], |
| 224 | "N."[!rnp->gp_tasks], |
| 225 | "E."[!rnp->exp_tasks], |
| 226 | "B."[!rnp->boost_tasks], |
| 227 | convert_kthread_status(rnp->boost_kthread_status), |
| 228 | rnp->n_tasks_boosted, rnp->n_exp_boosts, |
| 229 | rnp->n_normal_boosts); |
| 230 | seq_printf(m, "j=%04x bt=%04x\n", |
| 231 | (int)(jiffies & 0xffff), |
| 232 | (int)(rnp->boost_time & 0xffff)); |
| 233 | seq_printf(m, " balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n", |
| 234 | rnp->n_balk_blkd_tasks, |
| 235 | rnp->n_balk_exp_gp_tasks, |
| 236 | rnp->n_balk_boost_tasks, |
| 237 | rnp->n_balk_notblocked, |
| 238 | rnp->n_balk_notyet, |
| 239 | rnp->n_balk_nos); |
| 240 | } |
| 241 | |
| 242 | static int show_rcu_node_boost(struct seq_file *m, void *unused) |
| 243 | { |
| 244 | struct rcu_node *rnp; |
| 245 | |
| 246 | rcu_for_each_leaf_node(&rcu_preempt_state, rnp) |
| 247 | print_one_rcu_node_boost(m, rnp); |
| 248 | return 0; |
| 249 | } |
| 250 | |
| 251 | static int rcu_node_boost_open(struct inode *inode, struct file *file) |
| 252 | { |
| 253 | return single_open(file, show_rcu_node_boost, NULL); |
| 254 | } |
| 255 | |
| 256 | static const struct file_operations rcu_node_boost_fops = { |
| 257 | .owner = THIS_MODULE, |
| 258 | .open = rcu_node_boost_open, |
| 259 | .read = seq_read, |
| 260 | .llseek = no_llseek, |
| 261 | .release = single_release, |
| 262 | }; |
| 263 | |
| 264 | #endif /* #ifdef CONFIG_RCU_BOOST */ |
| 265 | |
| 266 | static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) |
| 267 | { |
| 268 | unsigned long gpnum; |
| 269 | int level = 0; |
| 270 | struct rcu_node *rnp; |
| 271 | |
| 272 | gpnum = rsp->gpnum; |
| 273 | seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x ", |
| 274 | ulong2long(rsp->completed), ulong2long(gpnum), |
| 275 | rsp->gp_state, |
| 276 | (long)(rsp->jiffies_force_qs - jiffies), |
| 277 | (int)(jiffies & 0xffff)); |
| 278 | seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n", |
| 279 | rsp->n_force_qs, rsp->n_force_qs_ngp, |
| 280 | rsp->n_force_qs - rsp->n_force_qs_ngp, |
| 281 | READ_ONCE(rsp->n_force_qs_lh), rsp->qlen_lazy, rsp->qlen); |
| 282 | for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) { |
| 283 | if (rnp->level != level) { |
| 284 | seq_puts(m, "\n"); |
| 285 | level = rnp->level; |
| 286 | } |
| 287 | seq_printf(m, "%lx/%lx->%lx %c%c>%c %d:%d ^%d ", |
| 288 | rnp->qsmask, rnp->qsmaskinit, rnp->qsmaskinitnext, |
| 289 | ".G"[rnp->gp_tasks != NULL], |
| 290 | ".E"[rnp->exp_tasks != NULL], |
| 291 | ".T"[!list_empty(&rnp->blkd_tasks)], |
| 292 | rnp->grplo, rnp->grphi, rnp->grpnum); |
| 293 | } |
| 294 | seq_puts(m, "\n"); |
| 295 | } |
| 296 | |
| 297 | static int show_rcuhier(struct seq_file *m, void *v) |
| 298 | { |
| 299 | struct rcu_state *rsp = (struct rcu_state *)m->private; |
| 300 | print_one_rcu_state(m, rsp); |
| 301 | return 0; |
| 302 | } |
| 303 | |
| 304 | static int rcuhier_open(struct inode *inode, struct file *file) |
| 305 | { |
| 306 | return single_open(file, show_rcuhier, inode->i_private); |
| 307 | } |
| 308 | |
| 309 | static const struct file_operations rcuhier_fops = { |
| 310 | .owner = THIS_MODULE, |
| 311 | .open = rcuhier_open, |
| 312 | .read = seq_read, |
| 313 | .llseek = no_llseek, |
| 314 | .release = single_release, |
| 315 | }; |
| 316 | |
| 317 | static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp) |
| 318 | { |
| 319 | unsigned long flags; |
| 320 | unsigned long completed; |
| 321 | unsigned long gpnum; |
| 322 | unsigned long gpage; |
| 323 | unsigned long gpmax; |
| 324 | struct rcu_node *rnp = &rsp->node[0]; |
| 325 | |
| 326 | raw_spin_lock_irqsave_rcu_node(rnp, flags); |
| 327 | completed = READ_ONCE(rsp->completed); |
| 328 | gpnum = READ_ONCE(rsp->gpnum); |
| 329 | if (completed == gpnum) |
| 330 | gpage = 0; |
| 331 | else |
| 332 | gpage = jiffies - rsp->gp_start; |
| 333 | gpmax = rsp->gp_max; |
| 334 | raw_spin_unlock_irqrestore(&rnp->lock, flags); |
| 335 | seq_printf(m, "completed=%ld gpnum=%ld age=%ld max=%ld\n", |
| 336 | ulong2long(completed), ulong2long(gpnum), gpage, gpmax); |
| 337 | } |
| 338 | |
| 339 | static int show_rcugp(struct seq_file *m, void *v) |
| 340 | { |
| 341 | struct rcu_state *rsp = (struct rcu_state *)m->private; |
| 342 | show_one_rcugp(m, rsp); |
| 343 | return 0; |
| 344 | } |
| 345 | |
| 346 | static int rcugp_open(struct inode *inode, struct file *file) |
| 347 | { |
| 348 | return single_open(file, show_rcugp, inode->i_private); |
| 349 | } |
| 350 | |
| 351 | static const struct file_operations rcugp_fops = { |
| 352 | .owner = THIS_MODULE, |
| 353 | .open = rcugp_open, |
| 354 | .read = seq_read, |
| 355 | .llseek = no_llseek, |
| 356 | .release = single_release, |
| 357 | }; |
| 358 | |
| 359 | static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp) |
| 360 | { |
| 361 | if (!rdp->beenonline) |
| 362 | return; |
| 363 | seq_printf(m, "%3d%cnp=%ld ", |
| 364 | rdp->cpu, |
| 365 | cpu_is_offline(rdp->cpu) ? '!' : ' ', |
| 366 | rdp->n_rcu_pending); |
| 367 | seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ", |
| 368 | rdp->n_rp_core_needs_qs, |
| 369 | rdp->n_rp_report_qs, |
| 370 | rdp->n_rp_cb_ready, |
| 371 | rdp->n_rp_cpu_needs_gp); |
| 372 | seq_printf(m, "gpc=%ld gps=%ld nn=%ld ndw%ld\n", |
| 373 | rdp->n_rp_gp_completed, |
| 374 | rdp->n_rp_gp_started, |
| 375 | rdp->n_rp_nocb_defer_wakeup, |
| 376 | rdp->n_rp_need_nothing); |
| 377 | } |
| 378 | |
| 379 | static int show_rcu_pending(struct seq_file *m, void *v) |
| 380 | { |
| 381 | print_one_rcu_pending(m, (struct rcu_data *)v); |
| 382 | return 0; |
| 383 | } |
| 384 | |
| 385 | static const struct seq_operations rcu_pending_op = { |
| 386 | .start = r_start, |
| 387 | .next = r_next, |
| 388 | .stop = r_stop, |
| 389 | .show = show_rcu_pending, |
| 390 | }; |
| 391 | |
| 392 | static int rcu_pending_open(struct inode *inode, struct file *file) |
| 393 | { |
| 394 | return r_open(inode, file, &rcu_pending_op); |
| 395 | } |
| 396 | |
| 397 | static const struct file_operations rcu_pending_fops = { |
| 398 | .owner = THIS_MODULE, |
| 399 | .open = rcu_pending_open, |
| 400 | .read = seq_read, |
| 401 | .llseek = no_llseek, |
| 402 | .release = seq_release, |
| 403 | }; |
| 404 | |
| 405 | static int show_rcutorture(struct seq_file *m, void *unused) |
| 406 | { |
| 407 | seq_printf(m, "rcutorture test sequence: %lu %s\n", |
| 408 | rcutorture_testseq >> 1, |
| 409 | (rcutorture_testseq & 0x1) ? "(test in progress)" : ""); |
| 410 | seq_printf(m, "rcutorture update version number: %lu\n", |
| 411 | rcutorture_vernum); |
| 412 | return 0; |
| 413 | } |
| 414 | |
| 415 | static int rcutorture_open(struct inode *inode, struct file *file) |
| 416 | { |
| 417 | return single_open(file, show_rcutorture, NULL); |
| 418 | } |
| 419 | |
| 420 | static const struct file_operations rcutorture_fops = { |
| 421 | .owner = THIS_MODULE, |
| 422 | .open = rcutorture_open, |
| 423 | .read = seq_read, |
| 424 | .llseek = seq_lseek, |
| 425 | .release = single_release, |
| 426 | }; |
| 427 | |
| 428 | static struct dentry *rcudir; |
| 429 | |
| 430 | static int __init rcutree_trace_init(void) |
| 431 | { |
| 432 | struct rcu_state *rsp; |
| 433 | struct dentry *retval; |
| 434 | struct dentry *rspdir; |
| 435 | |
| 436 | rcudir = debugfs_create_dir("rcu", NULL); |
| 437 | if (!rcudir) |
| 438 | goto free_out; |
| 439 | |
| 440 | for_each_rcu_flavor(rsp) { |
| 441 | rspdir = debugfs_create_dir(rsp->name, rcudir); |
| 442 | if (!rspdir) |
| 443 | goto free_out; |
| 444 | |
| 445 | retval = debugfs_create_file("rcudata", 0444, |
| 446 | rspdir, rsp, &rcudata_fops); |
| 447 | if (!retval) |
| 448 | goto free_out; |
| 449 | |
| 450 | retval = debugfs_create_file("rcuexp", 0444, |
| 451 | rspdir, rsp, &rcuexp_fops); |
| 452 | if (!retval) |
| 453 | goto free_out; |
| 454 | |
| 455 | retval = debugfs_create_file("rcu_pending", 0444, |
| 456 | rspdir, rsp, &rcu_pending_fops); |
| 457 | if (!retval) |
| 458 | goto free_out; |
| 459 | |
| 460 | retval = debugfs_create_file("rcubarrier", 0444, |
| 461 | rspdir, rsp, &rcubarrier_fops); |
| 462 | if (!retval) |
| 463 | goto free_out; |
| 464 | |
| 465 | #ifdef CONFIG_RCU_BOOST |
| 466 | if (rsp == &rcu_preempt_state) { |
| 467 | retval = debugfs_create_file("rcuboost", 0444, |
| 468 | rspdir, NULL, &rcu_node_boost_fops); |
| 469 | if (!retval) |
| 470 | goto free_out; |
| 471 | } |
| 472 | #endif |
| 473 | |
| 474 | retval = debugfs_create_file("rcugp", 0444, |
| 475 | rspdir, rsp, &rcugp_fops); |
| 476 | if (!retval) |
| 477 | goto free_out; |
| 478 | |
| 479 | retval = debugfs_create_file("rcuhier", 0444, |
| 480 | rspdir, rsp, &rcuhier_fops); |
| 481 | if (!retval) |
| 482 | goto free_out; |
| 483 | } |
| 484 | |
| 485 | retval = debugfs_create_file("rcutorture", 0444, rcudir, |
| 486 | NULL, &rcutorture_fops); |
| 487 | if (!retval) |
| 488 | goto free_out; |
| 489 | return 0; |
| 490 | free_out: |
| 491 | debugfs_remove_recursive(rcudir); |
| 492 | return 1; |
| 493 | } |
| 494 | device_initcall(rcutree_trace_init); |