1 // SPDX-License-Identifier: GPL-2.0 2 #include "util/debug.h" 3 #include "util/evlist.h" 4 #include "util/machine.h" 5 #include "util/map.h" 6 #include "util/symbol.h" 7 #include "util/target.h" 8 #include "util/thread.h" 9 #include "util/thread_map.h" 10 #include "util/lock-contention.h" 11 #include <linux/zalloc.h> 12 #include <linux/string.h> 13 #include <bpf/bpf.h> 14 15 #include "bpf_skel/lock_contention.skel.h" 16 #include "bpf_skel/lock_data.h" 17 18 static struct lock_contention_bpf *skel; 19 20 int lock_contention_prepare(struct lock_contention *con) 21 { 22 int i, fd; 23 int ncpus = 1, ntasks = 1, ntypes = 1, naddrs = 1; 24 struct evlist *evlist = con->evlist; 25 struct target *target = con->target; 26 27 skel = lock_contention_bpf__open(); 28 if (!skel) { 29 pr_err("Failed to open lock-contention BPF skeleton\n"); 30 return -1; 31 } 32 33 bpf_map__set_value_size(skel->maps.stacks, con->max_stack * sizeof(u64)); 34 bpf_map__set_max_entries(skel->maps.lock_stat, con->map_nr_entries); 35 bpf_map__set_max_entries(skel->maps.tstamp, con->map_nr_entries); 36 37 if (con->aggr_mode == LOCK_AGGR_TASK) 38 bpf_map__set_max_entries(skel->maps.task_data, con->map_nr_entries); 39 else 40 bpf_map__set_max_entries(skel->maps.task_data, 1); 41 42 if (con->save_callstack) 43 bpf_map__set_max_entries(skel->maps.stacks, con->map_nr_entries); 44 else 45 bpf_map__set_max_entries(skel->maps.stacks, 1); 46 47 if (target__has_cpu(target)) 48 ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus); 49 if (target__has_task(target)) 50 ntasks = perf_thread_map__nr(evlist->core.threads); 51 if (con->filters->nr_types) 52 ntypes = con->filters->nr_types; 53 54 /* resolve lock name filters to addr */ 55 if (con->filters->nr_syms) { 56 struct symbol *sym; 57 struct map *kmap; 58 unsigned long *addrs; 59 60 for (i = 0; i < con->filters->nr_syms; i++) { 61 sym = machine__find_kernel_symbol_by_name(con->machine, 62 con->filters->syms[i], 63 &kmap); 64 if (sym == NULL) { 65 pr_warning("ignore unknown symbol: %s\n", 66 con->filters->syms[i]); 67 continue; 68 } 69 70 addrs = realloc(con->filters->addrs, 71 (con->filters->nr_addrs + 1) * sizeof(*addrs)); 72 if (addrs == NULL) { 73 pr_warning("memory allocation failure\n"); 74 continue; 75 } 76 77 addrs[con->filters->nr_addrs++] = kmap->unmap_ip(kmap, sym->start); 78 con->filters->addrs = addrs; 79 } 80 naddrs = con->filters->nr_addrs; 81 } 82 83 bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus); 84 bpf_map__set_max_entries(skel->maps.task_filter, ntasks); 85 bpf_map__set_max_entries(skel->maps.type_filter, ntypes); 86 bpf_map__set_max_entries(skel->maps.addr_filter, naddrs); 87 88 if (lock_contention_bpf__load(skel) < 0) { 89 pr_err("Failed to load lock-contention BPF skeleton\n"); 90 return -1; 91 } 92 93 if (target__has_cpu(target)) { 94 u32 cpu; 95 u8 val = 1; 96 97 skel->bss->has_cpu = 1; 98 fd = bpf_map__fd(skel->maps.cpu_filter); 99 100 for (i = 0; i < ncpus; i++) { 101 cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu; 102 bpf_map_update_elem(fd, &cpu, &val, BPF_ANY); 103 } 104 } 105 106 if (target__has_task(target)) { 107 u32 pid; 108 u8 val = 1; 109 110 skel->bss->has_task = 1; 111 fd = bpf_map__fd(skel->maps.task_filter); 112 113 for (i = 0; i < ntasks; i++) { 114 pid = perf_thread_map__pid(evlist->core.threads, i); 115 bpf_map_update_elem(fd, &pid, &val, BPF_ANY); 116 } 117 } 118 119 if (target__none(target) && evlist->workload.pid > 0) { 120 u32 pid = evlist->workload.pid; 121 u8 val = 1; 122 123 skel->bss->has_task = 1; 124 fd = bpf_map__fd(skel->maps.task_filter); 125 bpf_map_update_elem(fd, &pid, &val, BPF_ANY); 126 } 127 128 if (con->filters->nr_types) { 129 u8 val = 1; 130 131 skel->bss->has_type = 1; 132 fd = bpf_map__fd(skel->maps.type_filter); 133 134 for (i = 0; i < con->filters->nr_types; i++) 135 bpf_map_update_elem(fd, &con->filters->types[i], &val, BPF_ANY); 136 } 137 138 if (con->filters->nr_addrs) { 139 u8 val = 1; 140 141 skel->bss->has_addr = 1; 142 fd = bpf_map__fd(skel->maps.addr_filter); 143 144 for (i = 0; i < con->filters->nr_addrs; i++) 145 bpf_map_update_elem(fd, &con->filters->addrs[i], &val, BPF_ANY); 146 } 147 148 /* these don't work well if in the rodata section */ 149 skel->bss->stack_skip = con->stack_skip; 150 skel->bss->aggr_mode = con->aggr_mode; 151 skel->bss->needs_callstack = con->save_callstack; 152 skel->bss->lock_owner = con->owner; 153 154 lock_contention_bpf__attach(skel); 155 return 0; 156 } 157 158 int lock_contention_start(void) 159 { 160 skel->bss->enabled = 1; 161 return 0; 162 } 163 164 int lock_contention_stop(void) 165 { 166 skel->bss->enabled = 0; 167 return 0; 168 } 169 170 static const char *lock_contention_get_name(struct lock_contention *con, 171 struct contention_key *key, 172 u64 *stack_trace) 173 { 174 int idx = 0; 175 u64 addr; 176 const char *name = ""; 177 static char name_buf[KSYM_NAME_LEN]; 178 struct symbol *sym; 179 struct map *kmap; 180 struct machine *machine = con->machine; 181 182 if (con->aggr_mode == LOCK_AGGR_TASK) { 183 struct contention_task_data task; 184 int pid = key->pid; 185 int task_fd = bpf_map__fd(skel->maps.task_data); 186 187 /* do not update idle comm which contains CPU number */ 188 if (pid) { 189 struct thread *t = __machine__findnew_thread(machine, /*pid=*/-1, pid); 190 191 if (t == NULL) 192 return name; 193 if (!bpf_map_lookup_elem(task_fd, &pid, &task) && 194 thread__set_comm(t, task.comm, /*timestamp=*/0)) 195 name = task.comm; 196 } 197 return name; 198 } 199 200 if (con->aggr_mode == LOCK_AGGR_ADDR) { 201 sym = machine__find_kernel_symbol(machine, key->lock_addr, &kmap); 202 if (sym) 203 name = sym->name; 204 return name; 205 } 206 207 /* LOCK_AGGR_CALLER: skip lock internal functions */ 208 while (machine__is_lock_function(machine, stack_trace[idx]) && 209 idx < con->max_stack - 1) 210 idx++; 211 212 addr = stack_trace[idx]; 213 sym = machine__find_kernel_symbol(machine, addr, &kmap); 214 215 if (sym) { 216 unsigned long offset; 217 218 offset = kmap->map_ip(kmap, addr) - sym->start; 219 220 if (offset == 0) 221 return sym->name; 222 223 snprintf(name_buf, sizeof(name_buf), "%s+%#lx", sym->name, offset); 224 } else { 225 snprintf(name_buf, sizeof(name_buf), "%#lx", (unsigned long)addr); 226 } 227 228 return name_buf; 229 } 230 231 int lock_contention_read(struct lock_contention *con) 232 { 233 int fd, stack, err = 0; 234 struct contention_key *prev_key, key; 235 struct contention_data data = {}; 236 struct lock_stat *st = NULL; 237 struct machine *machine = con->machine; 238 u64 *stack_trace; 239 size_t stack_size = con->max_stack * sizeof(*stack_trace); 240 241 fd = bpf_map__fd(skel->maps.lock_stat); 242 stack = bpf_map__fd(skel->maps.stacks); 243 244 con->lost = skel->bss->lost; 245 246 stack_trace = zalloc(stack_size); 247 if (stack_trace == NULL) 248 return -1; 249 250 if (con->aggr_mode == LOCK_AGGR_TASK) { 251 struct thread *idle = __machine__findnew_thread(machine, 252 /*pid=*/0, 253 /*tid=*/0); 254 thread__set_comm(idle, "swapper", /*timestamp=*/0); 255 } 256 257 /* make sure it loads the kernel map */ 258 map__load(maps__first(machine->kmaps)); 259 260 prev_key = NULL; 261 while (!bpf_map_get_next_key(fd, prev_key, &key)) { 262 s64 ls_key; 263 const char *name; 264 265 /* to handle errors in the loop body */ 266 err = -1; 267 268 bpf_map_lookup_elem(fd, &key, &data); 269 if (con->save_callstack) { 270 bpf_map_lookup_elem(stack, &key.stack_id, stack_trace); 271 272 if (!match_callstack_filter(machine, stack_trace)) 273 goto next; 274 } 275 276 switch (con->aggr_mode) { 277 case LOCK_AGGR_CALLER: 278 ls_key = key.stack_id; 279 break; 280 case LOCK_AGGR_TASK: 281 ls_key = key.pid; 282 break; 283 case LOCK_AGGR_ADDR: 284 ls_key = key.lock_addr; 285 break; 286 default: 287 goto next; 288 } 289 290 st = lock_stat_find(ls_key); 291 if (st != NULL) { 292 st->wait_time_total += data.total_time; 293 if (st->wait_time_max < data.max_time) 294 st->wait_time_max = data.max_time; 295 if (st->wait_time_min > data.min_time) 296 st->wait_time_min = data.min_time; 297 298 st->nr_contended += data.count; 299 if (st->nr_contended) 300 st->avg_wait_time = st->wait_time_total / st->nr_contended; 301 goto next; 302 } 303 304 name = lock_contention_get_name(con, &key, stack_trace); 305 st = lock_stat_findnew(ls_key, name, data.flags); 306 if (st == NULL) 307 break; 308 309 st->nr_contended = data.count; 310 st->wait_time_total = data.total_time; 311 st->wait_time_max = data.max_time; 312 st->wait_time_min = data.min_time; 313 314 if (data.count) 315 st->avg_wait_time = data.total_time / data.count; 316 317 if (con->save_callstack) { 318 st->callstack = memdup(stack_trace, stack_size); 319 if (st->callstack == NULL) 320 break; 321 } 322 323 next: 324 prev_key = &key; 325 326 /* we're fine now, reset the error */ 327 err = 0; 328 } 329 330 free(stack_trace); 331 332 return err; 333 } 334 335 int lock_contention_finish(void) 336 { 337 if (skel) { 338 skel->bss->enabled = 0; 339 lock_contention_bpf__destroy(skel); 340 } 341 342 return 0; 343 } 344