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 int lock_contention_start(void) 183 { 184 skel->bss->enabled = 1; 185 return 0; 186 } 187 188 int lock_contention_stop(void) 189 { 190 skel->bss->enabled = 0; 191 return 0; 192 } 193 194 static const char *lock_contention_get_name(struct lock_contention *con, 195 struct contention_key *key, 196 u64 *stack_trace, u32 flags) 197 { 198 int idx = 0; 199 u64 addr; 200 const char *name = ""; 201 static char name_buf[KSYM_NAME_LEN]; 202 struct symbol *sym; 203 struct map *kmap; 204 struct machine *machine = con->machine; 205 206 if (con->aggr_mode == LOCK_AGGR_TASK) { 207 struct contention_task_data task; 208 int pid = key->pid; 209 int task_fd = bpf_map__fd(skel->maps.task_data); 210 211 /* do not update idle comm which contains CPU number */ 212 if (pid) { 213 struct thread *t = __machine__findnew_thread(machine, /*pid=*/-1, pid); 214 215 if (t == NULL) 216 return name; 217 if (!bpf_map_lookup_elem(task_fd, &pid, &task) && 218 thread__set_comm(t, task.comm, /*timestamp=*/0)) 219 name = task.comm; 220 } 221 return name; 222 } 223 224 if (con->aggr_mode == LOCK_AGGR_ADDR) { 225 int lock_fd = bpf_map__fd(skel->maps.lock_syms); 226 227 /* per-process locks set upper bits of the flags */ 228 if (flags & LCD_F_MMAP_LOCK) 229 return "mmap_lock"; 230 if (flags & LCD_F_SIGHAND_LOCK) 231 return "siglock"; 232 233 /* global locks with symbols */ 234 sym = machine__find_kernel_symbol(machine, key->lock_addr_or_cgroup, &kmap); 235 if (sym) 236 return sym->name; 237 238 /* try semi-global locks collected separately */ 239 if (!bpf_map_lookup_elem(lock_fd, &key->lock_addr_or_cgroup, &flags)) { 240 if (flags == LOCK_CLASS_RQLOCK) 241 return "rq_lock"; 242 } 243 244 return ""; 245 } 246 247 if (con->aggr_mode == LOCK_AGGR_CGROUP) { 248 u64 cgrp_id = key->lock_addr_or_cgroup; 249 struct cgroup *cgrp = __cgroup__find(&con->cgroups, cgrp_id); 250 251 if (cgrp) 252 return cgrp->name; 253 254 snprintf(name_buf, sizeof(name_buf), "cgroup:%" PRIu64 "", cgrp_id); 255 return name_buf; 256 } 257 258 /* LOCK_AGGR_CALLER: skip lock internal functions */ 259 while (machine__is_lock_function(machine, stack_trace[idx]) && 260 idx < con->max_stack - 1) 261 idx++; 262 263 addr = stack_trace[idx]; 264 sym = machine__find_kernel_symbol(machine, addr, &kmap); 265 266 if (sym) { 267 unsigned long offset; 268 269 offset = map__map_ip(kmap, addr) - sym->start; 270 271 if (offset == 0) 272 return sym->name; 273 274 snprintf(name_buf, sizeof(name_buf), "%s+%#lx", sym->name, offset); 275 } else { 276 snprintf(name_buf, sizeof(name_buf), "%#lx", (unsigned long)addr); 277 } 278 279 return name_buf; 280 } 281 282 int lock_contention_read(struct lock_contention *con) 283 { 284 int fd, stack, err = 0; 285 struct contention_key *prev_key, key = {}; 286 struct contention_data data = {}; 287 struct lock_stat *st = NULL; 288 struct machine *machine = con->machine; 289 u64 *stack_trace; 290 size_t stack_size = con->max_stack * sizeof(*stack_trace); 291 292 fd = bpf_map__fd(skel->maps.lock_stat); 293 stack = bpf_map__fd(skel->maps.stacks); 294 295 con->fails.task = skel->bss->task_fail; 296 con->fails.stack = skel->bss->stack_fail; 297 con->fails.time = skel->bss->time_fail; 298 con->fails.data = skel->bss->data_fail; 299 300 stack_trace = zalloc(stack_size); 301 if (stack_trace == NULL) 302 return -1; 303 304 if (con->aggr_mode == LOCK_AGGR_TASK) { 305 struct thread *idle = __machine__findnew_thread(machine, 306 /*pid=*/0, 307 /*tid=*/0); 308 thread__set_comm(idle, "swapper", /*timestamp=*/0); 309 } 310 311 if (con->aggr_mode == LOCK_AGGR_ADDR) { 312 DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts, 313 .flags = BPF_F_TEST_RUN_ON_CPU, 314 ); 315 int prog_fd = bpf_program__fd(skel->progs.collect_lock_syms); 316 317 bpf_prog_test_run_opts(prog_fd, &opts); 318 } 319 320 /* make sure it loads the kernel map */ 321 maps__load_first(machine->kmaps); 322 323 prev_key = NULL; 324 while (!bpf_map_get_next_key(fd, prev_key, &key)) { 325 s64 ls_key; 326 const char *name; 327 328 /* to handle errors in the loop body */ 329 err = -1; 330 331 bpf_map_lookup_elem(fd, &key, &data); 332 if (con->save_callstack) { 333 bpf_map_lookup_elem(stack, &key.stack_id, stack_trace); 334 335 if (!match_callstack_filter(machine, stack_trace)) { 336 con->nr_filtered += data.count; 337 goto next; 338 } 339 } 340 341 switch (con->aggr_mode) { 342 case LOCK_AGGR_CALLER: 343 ls_key = key.stack_id; 344 break; 345 case LOCK_AGGR_TASK: 346 ls_key = key.pid; 347 break; 348 case LOCK_AGGR_ADDR: 349 case LOCK_AGGR_CGROUP: 350 ls_key = key.lock_addr_or_cgroup; 351 break; 352 default: 353 goto next; 354 } 355 356 st = lock_stat_find(ls_key); 357 if (st != NULL) { 358 st->wait_time_total += data.total_time; 359 if (st->wait_time_max < data.max_time) 360 st->wait_time_max = data.max_time; 361 if (st->wait_time_min > data.min_time) 362 st->wait_time_min = data.min_time; 363 364 st->nr_contended += data.count; 365 if (st->nr_contended) 366 st->avg_wait_time = st->wait_time_total / st->nr_contended; 367 goto next; 368 } 369 370 name = lock_contention_get_name(con, &key, stack_trace, data.flags); 371 st = lock_stat_findnew(ls_key, name, data.flags); 372 if (st == NULL) 373 break; 374 375 st->nr_contended = data.count; 376 st->wait_time_total = data.total_time; 377 st->wait_time_max = data.max_time; 378 st->wait_time_min = data.min_time; 379 380 if (data.count) 381 st->avg_wait_time = data.total_time / data.count; 382 383 if (con->aggr_mode == LOCK_AGGR_CALLER && verbose > 0) { 384 st->callstack = memdup(stack_trace, stack_size); 385 if (st->callstack == NULL) 386 break; 387 } 388 389 next: 390 prev_key = &key; 391 392 /* we're fine now, reset the error */ 393 err = 0; 394 } 395 396 free(stack_trace); 397 398 return err; 399 } 400 401 int lock_contention_finish(struct lock_contention *con) 402 { 403 if (skel) { 404 skel->bss->enabled = 0; 405 lock_contention_bpf__destroy(skel); 406 } 407 408 while (!RB_EMPTY_ROOT(&con->cgroups)) { 409 struct rb_node *node = rb_first(&con->cgroups); 410 struct cgroup *cgrp = rb_entry(node, struct cgroup, node); 411 412 rb_erase(node, &con->cgroups); 413 cgroup__put(cgrp); 414 } 415 416 return 0; 417 } 418