1 // SPDX-License-Identifier: GPL-2.0 2 #include "util/cgroup.h" 3 #include "util/debug.h" 4 #include "util/evlist.h" 5 #include "util/machine.h" 6 #include "util/map.h" 7 #include "util/symbol.h" 8 #include "util/target.h" 9 #include "util/thread.h" 10 #include "util/thread_map.h" 11 #include "util/lock-contention.h" 12 #include <linux/zalloc.h> 13 #include <linux/string.h> 14 #include <bpf/bpf.h> 15 #include <inttypes.h> 16 17 #include "bpf_skel/lock_contention.skel.h" 18 #include "bpf_skel/lock_data.h" 19 20 static struct lock_contention_bpf *skel; 21 22 int lock_contention_prepare(struct lock_contention *con) 23 { 24 int i, fd; 25 int ncpus = 1, ntasks = 1, ntypes = 1, naddrs = 1, ncgrps = 1; 26 struct evlist *evlist = con->evlist; 27 struct target *target = con->target; 28 29 skel = lock_contention_bpf__open(); 30 if (!skel) { 31 pr_err("Failed to open lock-contention BPF skeleton\n"); 32 return -1; 33 } 34 35 bpf_map__set_value_size(skel->maps.stacks, con->max_stack * sizeof(u64)); 36 bpf_map__set_max_entries(skel->maps.lock_stat, con->map_nr_entries); 37 bpf_map__set_max_entries(skel->maps.tstamp, con->map_nr_entries); 38 39 if (con->aggr_mode == LOCK_AGGR_TASK) 40 bpf_map__set_max_entries(skel->maps.task_data, con->map_nr_entries); 41 else 42 bpf_map__set_max_entries(skel->maps.task_data, 1); 43 44 if (con->save_callstack) 45 bpf_map__set_max_entries(skel->maps.stacks, con->map_nr_entries); 46 else 47 bpf_map__set_max_entries(skel->maps.stacks, 1); 48 49 if (target__has_cpu(target)) 50 ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus); 51 if (target__has_task(target)) 52 ntasks = perf_thread_map__nr(evlist->core.threads); 53 if (con->filters->nr_types) 54 ntypes = con->filters->nr_types; 55 if (con->filters->nr_cgrps) 56 ncgrps = con->filters->nr_cgrps; 57 58 /* resolve lock name filters to addr */ 59 if (con->filters->nr_syms) { 60 struct symbol *sym; 61 struct map *kmap; 62 unsigned long *addrs; 63 64 for (i = 0; i < con->filters->nr_syms; i++) { 65 sym = machine__find_kernel_symbol_by_name(con->machine, 66 con->filters->syms[i], 67 &kmap); 68 if (sym == NULL) { 69 pr_warning("ignore unknown symbol: %s\n", 70 con->filters->syms[i]); 71 continue; 72 } 73 74 addrs = realloc(con->filters->addrs, 75 (con->filters->nr_addrs + 1) * sizeof(*addrs)); 76 if (addrs == NULL) { 77 pr_warning("memory allocation failure\n"); 78 continue; 79 } 80 81 addrs[con->filters->nr_addrs++] = map__unmap_ip(kmap, sym->start); 82 con->filters->addrs = addrs; 83 } 84 naddrs = con->filters->nr_addrs; 85 } 86 87 bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus); 88 bpf_map__set_max_entries(skel->maps.task_filter, ntasks); 89 bpf_map__set_max_entries(skel->maps.type_filter, ntypes); 90 bpf_map__set_max_entries(skel->maps.addr_filter, naddrs); 91 bpf_map__set_max_entries(skel->maps.cgroup_filter, ncgrps); 92 93 if (lock_contention_bpf__load(skel) < 0) { 94 pr_err("Failed to load lock-contention BPF skeleton\n"); 95 return -1; 96 } 97 98 if (target__has_cpu(target)) { 99 u32 cpu; 100 u8 val = 1; 101 102 skel->bss->has_cpu = 1; 103 fd = bpf_map__fd(skel->maps.cpu_filter); 104 105 for (i = 0; i < ncpus; i++) { 106 cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu; 107 bpf_map_update_elem(fd, &cpu, &val, BPF_ANY); 108 } 109 } 110 111 if (target__has_task(target)) { 112 u32 pid; 113 u8 val = 1; 114 115 skel->bss->has_task = 1; 116 fd = bpf_map__fd(skel->maps.task_filter); 117 118 for (i = 0; i < ntasks; i++) { 119 pid = perf_thread_map__pid(evlist->core.threads, i); 120 bpf_map_update_elem(fd, &pid, &val, BPF_ANY); 121 } 122 } 123 124 if (target__none(target) && evlist->workload.pid > 0) { 125 u32 pid = evlist->workload.pid; 126 u8 val = 1; 127 128 skel->bss->has_task = 1; 129 fd = bpf_map__fd(skel->maps.task_filter); 130 bpf_map_update_elem(fd, &pid, &val, BPF_ANY); 131 } 132 133 if (con->filters->nr_types) { 134 u8 val = 1; 135 136 skel->bss->has_type = 1; 137 fd = bpf_map__fd(skel->maps.type_filter); 138 139 for (i = 0; i < con->filters->nr_types; i++) 140 bpf_map_update_elem(fd, &con->filters->types[i], &val, BPF_ANY); 141 } 142 143 if (con->filters->nr_addrs) { 144 u8 val = 1; 145 146 skel->bss->has_addr = 1; 147 fd = bpf_map__fd(skel->maps.addr_filter); 148 149 for (i = 0; i < con->filters->nr_addrs; i++) 150 bpf_map_update_elem(fd, &con->filters->addrs[i], &val, BPF_ANY); 151 } 152 153 if (con->filters->nr_cgrps) { 154 u8 val = 1; 155 156 skel->bss->has_cgroup = 1; 157 fd = bpf_map__fd(skel->maps.cgroup_filter); 158 159 for (i = 0; i < con->filters->nr_cgrps; i++) 160 bpf_map_update_elem(fd, &con->filters->cgrps[i], &val, BPF_ANY); 161 } 162 163 /* these don't work well if in the rodata section */ 164 skel->bss->stack_skip = con->stack_skip; 165 skel->bss->aggr_mode = con->aggr_mode; 166 skel->bss->needs_callstack = con->save_callstack; 167 skel->bss->lock_owner = con->owner; 168 169 if (con->aggr_mode == LOCK_AGGR_CGROUP) { 170 if (cgroup_is_v2("perf_event")) 171 skel->bss->use_cgroup_v2 = 1; 172 173 read_all_cgroups(&con->cgroups); 174 } 175 176 bpf_program__set_autoload(skel->progs.collect_lock_syms, false); 177 178 lock_contention_bpf__attach(skel); 179 return 0; 180 } 181 182 /* 183 * Run the BPF program directly using BPF_PROG_TEST_RUN to update the end 184 * timestamp in ktime so that it can calculate delta easily. 185 */ 186 static void mark_end_timestamp(void) 187 { 188 DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts, 189 .flags = BPF_F_TEST_RUN_ON_CPU, 190 ); 191 int prog_fd = bpf_program__fd(skel->progs.end_timestamp); 192 193 bpf_prog_test_run_opts(prog_fd, &opts); 194 } 195 196 static void update_lock_stat(int map_fd, int pid, u64 end_ts, 197 enum lock_aggr_mode aggr_mode, 198 struct tstamp_data *ts_data) 199 { 200 u64 delta; 201 struct contention_key stat_key = {}; 202 struct contention_data stat_data; 203 204 if (ts_data->timestamp >= end_ts) 205 return; 206 207 delta = end_ts - ts_data->timestamp; 208 209 switch (aggr_mode) { 210 case LOCK_AGGR_CALLER: 211 stat_key.stack_id = ts_data->stack_id; 212 break; 213 case LOCK_AGGR_TASK: 214 stat_key.pid = pid; 215 break; 216 case LOCK_AGGR_ADDR: 217 stat_key.lock_addr_or_cgroup = ts_data->lock; 218 break; 219 case LOCK_AGGR_CGROUP: 220 /* TODO */ 221 return; 222 default: 223 return; 224 } 225 226 if (bpf_map_lookup_elem(map_fd, &stat_key, &stat_data) < 0) 227 return; 228 229 stat_data.total_time += delta; 230 stat_data.count++; 231 232 if (delta > stat_data.max_time) 233 stat_data.max_time = delta; 234 if (delta < stat_data.min_time) 235 stat_data.min_time = delta; 236 237 bpf_map_update_elem(map_fd, &stat_key, &stat_data, BPF_EXIST); 238 } 239 240 /* 241 * Account entries in the tstamp map (which didn't see the corresponding 242 * lock:contention_end tracepoint) using end_ts. 243 */ 244 static void account_end_timestamp(struct lock_contention *con) 245 { 246 int ts_fd, stat_fd; 247 int *prev_key, key; 248 u64 end_ts = skel->bss->end_ts; 249 int total_cpus; 250 enum lock_aggr_mode aggr_mode = con->aggr_mode; 251 struct tstamp_data ts_data, *cpu_data; 252 253 /* Iterate per-task tstamp map (key = TID) */ 254 ts_fd = bpf_map__fd(skel->maps.tstamp); 255 stat_fd = bpf_map__fd(skel->maps.lock_stat); 256 257 prev_key = NULL; 258 while (!bpf_map_get_next_key(ts_fd, prev_key, &key)) { 259 if (bpf_map_lookup_elem(ts_fd, &key, &ts_data) == 0) { 260 int pid = key; 261 262 if (aggr_mode == LOCK_AGGR_TASK && con->owner) 263 pid = ts_data.flags; 264 265 update_lock_stat(stat_fd, pid, end_ts, aggr_mode, 266 &ts_data); 267 } 268 269 prev_key = &key; 270 } 271 272 /* Now it'll check per-cpu tstamp map which doesn't have TID. */ 273 if (aggr_mode == LOCK_AGGR_TASK || aggr_mode == LOCK_AGGR_CGROUP) 274 return; 275 276 total_cpus = cpu__max_cpu().cpu; 277 ts_fd = bpf_map__fd(skel->maps.tstamp_cpu); 278 279 cpu_data = calloc(total_cpus, sizeof(*cpu_data)); 280 if (cpu_data == NULL) 281 return; 282 283 prev_key = NULL; 284 while (!bpf_map_get_next_key(ts_fd, prev_key, &key)) { 285 if (bpf_map_lookup_elem(ts_fd, &key, cpu_data) < 0) 286 goto next; 287 288 for (int i = 0; i < total_cpus; i++) { 289 update_lock_stat(stat_fd, -1, end_ts, aggr_mode, 290 &cpu_data[i]); 291 } 292 293 next: 294 prev_key = &key; 295 } 296 free(cpu_data); 297 } 298 299 int lock_contention_start(void) 300 { 301 skel->bss->enabled = 1; 302 return 0; 303 } 304 305 int lock_contention_stop(void) 306 { 307 skel->bss->enabled = 0; 308 mark_end_timestamp(); 309 return 0; 310 } 311 312 static const char *lock_contention_get_name(struct lock_contention *con, 313 struct contention_key *key, 314 u64 *stack_trace, u32 flags) 315 { 316 int idx = 0; 317 u64 addr; 318 const char *name = ""; 319 static char name_buf[KSYM_NAME_LEN]; 320 struct symbol *sym; 321 struct map *kmap; 322 struct machine *machine = con->machine; 323 324 if (con->aggr_mode == LOCK_AGGR_TASK) { 325 struct contention_task_data task; 326 int pid = key->pid; 327 int task_fd = bpf_map__fd(skel->maps.task_data); 328 329 /* do not update idle comm which contains CPU number */ 330 if (pid) { 331 struct thread *t = machine__findnew_thread(machine, /*pid=*/-1, pid); 332 333 if (t == NULL) 334 return name; 335 if (!bpf_map_lookup_elem(task_fd, &pid, &task) && 336 thread__set_comm(t, task.comm, /*timestamp=*/0)) 337 name = task.comm; 338 } 339 return name; 340 } 341 342 if (con->aggr_mode == LOCK_AGGR_ADDR) { 343 int lock_fd = bpf_map__fd(skel->maps.lock_syms); 344 345 /* per-process locks set upper bits of the flags */ 346 if (flags & LCD_F_MMAP_LOCK) 347 return "mmap_lock"; 348 if (flags & LCD_F_SIGHAND_LOCK) 349 return "siglock"; 350 351 /* global locks with symbols */ 352 sym = machine__find_kernel_symbol(machine, key->lock_addr_or_cgroup, &kmap); 353 if (sym) 354 return sym->name; 355 356 /* try semi-global locks collected separately */ 357 if (!bpf_map_lookup_elem(lock_fd, &key->lock_addr_or_cgroup, &flags)) { 358 if (flags == LOCK_CLASS_RQLOCK) 359 return "rq_lock"; 360 } 361 362 return ""; 363 } 364 365 if (con->aggr_mode == LOCK_AGGR_CGROUP) { 366 u64 cgrp_id = key->lock_addr_or_cgroup; 367 struct cgroup *cgrp = __cgroup__find(&con->cgroups, cgrp_id); 368 369 if (cgrp) 370 return cgrp->name; 371 372 snprintf(name_buf, sizeof(name_buf), "cgroup:%" PRIu64 "", cgrp_id); 373 return name_buf; 374 } 375 376 /* LOCK_AGGR_CALLER: skip lock internal functions */ 377 while (machine__is_lock_function(machine, stack_trace[idx]) && 378 idx < con->max_stack - 1) 379 idx++; 380 381 addr = stack_trace[idx]; 382 sym = machine__find_kernel_symbol(machine, addr, &kmap); 383 384 if (sym) { 385 unsigned long offset; 386 387 offset = map__map_ip(kmap, addr) - sym->start; 388 389 if (offset == 0) 390 return sym->name; 391 392 snprintf(name_buf, sizeof(name_buf), "%s+%#lx", sym->name, offset); 393 } else { 394 snprintf(name_buf, sizeof(name_buf), "%#lx", (unsigned long)addr); 395 } 396 397 return name_buf; 398 } 399 400 int lock_contention_read(struct lock_contention *con) 401 { 402 int fd, stack, err = 0; 403 struct contention_key *prev_key, key = {}; 404 struct contention_data data = {}; 405 struct lock_stat *st = NULL; 406 struct machine *machine = con->machine; 407 u64 *stack_trace; 408 size_t stack_size = con->max_stack * sizeof(*stack_trace); 409 410 fd = bpf_map__fd(skel->maps.lock_stat); 411 stack = bpf_map__fd(skel->maps.stacks); 412 413 con->fails.task = skel->bss->task_fail; 414 con->fails.stack = skel->bss->stack_fail; 415 con->fails.time = skel->bss->time_fail; 416 con->fails.data = skel->bss->data_fail; 417 418 stack_trace = zalloc(stack_size); 419 if (stack_trace == NULL) 420 return -1; 421 422 account_end_timestamp(con); 423 424 if (con->aggr_mode == LOCK_AGGR_TASK) { 425 struct thread *idle = machine__findnew_thread(machine, 426 /*pid=*/0, 427 /*tid=*/0); 428 thread__set_comm(idle, "swapper", /*timestamp=*/0); 429 } 430 431 if (con->aggr_mode == LOCK_AGGR_ADDR) { 432 DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts, 433 .flags = BPF_F_TEST_RUN_ON_CPU, 434 ); 435 int prog_fd = bpf_program__fd(skel->progs.collect_lock_syms); 436 437 bpf_prog_test_run_opts(prog_fd, &opts); 438 } 439 440 /* make sure it loads the kernel map */ 441 maps__load_first(machine->kmaps); 442 443 prev_key = NULL; 444 while (!bpf_map_get_next_key(fd, prev_key, &key)) { 445 s64 ls_key; 446 const char *name; 447 448 /* to handle errors in the loop body */ 449 err = -1; 450 451 bpf_map_lookup_elem(fd, &key, &data); 452 if (con->save_callstack) { 453 bpf_map_lookup_elem(stack, &key.stack_id, stack_trace); 454 455 if (!match_callstack_filter(machine, stack_trace)) { 456 con->nr_filtered += data.count; 457 goto next; 458 } 459 } 460 461 switch (con->aggr_mode) { 462 case LOCK_AGGR_CALLER: 463 ls_key = key.stack_id; 464 break; 465 case LOCK_AGGR_TASK: 466 ls_key = key.pid; 467 break; 468 case LOCK_AGGR_ADDR: 469 case LOCK_AGGR_CGROUP: 470 ls_key = key.lock_addr_or_cgroup; 471 break; 472 default: 473 goto next; 474 } 475 476 st = lock_stat_find(ls_key); 477 if (st != NULL) { 478 st->wait_time_total += data.total_time; 479 if (st->wait_time_max < data.max_time) 480 st->wait_time_max = data.max_time; 481 if (st->wait_time_min > data.min_time) 482 st->wait_time_min = data.min_time; 483 484 st->nr_contended += data.count; 485 if (st->nr_contended) 486 st->avg_wait_time = st->wait_time_total / st->nr_contended; 487 goto next; 488 } 489 490 name = lock_contention_get_name(con, &key, stack_trace, data.flags); 491 st = lock_stat_findnew(ls_key, name, data.flags); 492 if (st == NULL) 493 break; 494 495 st->nr_contended = data.count; 496 st->wait_time_total = data.total_time; 497 st->wait_time_max = data.max_time; 498 st->wait_time_min = data.min_time; 499 500 if (data.count) 501 st->avg_wait_time = data.total_time / data.count; 502 503 if (con->aggr_mode == LOCK_AGGR_CALLER && verbose > 0) { 504 st->callstack = memdup(stack_trace, stack_size); 505 if (st->callstack == NULL) 506 break; 507 } 508 509 next: 510 prev_key = &key; 511 512 /* we're fine now, reset the error */ 513 err = 0; 514 } 515 516 free(stack_trace); 517 518 return err; 519 } 520 521 int lock_contention_finish(struct lock_contention *con) 522 { 523 if (skel) { 524 skel->bss->enabled = 0; 525 lock_contention_bpf__destroy(skel); 526 } 527 528 while (!RB_EMPTY_ROOT(&con->cgroups)) { 529 struct rb_node *node = rb_first(&con->cgroups); 530 struct cgroup *cgrp = rb_entry(node, struct cgroup, node); 531 532 rb_erase(node, &con->cgroups); 533 cgroup__put(cgrp); 534 } 535 536 return 0; 537 } 538