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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
18static struct lock_contention_bpf *skel;
19
20int 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 bpf_map__set_max_entries(skel->maps.stacks, 1);
40 } else {
41 bpf_map__set_max_entries(skel->maps.task_data, 1);
42 bpf_map__set_max_entries(skel->maps.stacks, con->map_nr_entries);
43 }
44
45 if (target__has_cpu(target))
46 ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
47 if (target__has_task(target))
48 ntasks = perf_thread_map__nr(evlist->core.threads);
49 if (con->filters->nr_types)
50 ntypes = con->filters->nr_types;
51
52 /* resolve lock name filters to addr */
53 if (con->filters->nr_syms) {
54 struct symbol *sym;
55 struct map *kmap;
56 unsigned long *addrs;
57
58 for (i = 0; i < con->filters->nr_syms; i++) {
59 sym = machine__find_kernel_symbol_by_name(con->machine,
60 con->filters->syms[i],
61 &kmap);
62 if (sym == NULL) {
63 pr_warning("ignore unknown symbol: %s\n",
64 con->filters->syms[i]);
65 continue;
66 }
67
68 addrs = realloc(con->filters->addrs,
69 (con->filters->nr_addrs + 1) * sizeof(*addrs));
70 if (addrs == NULL) {
71 pr_warning("memory allocation failure\n");
72 continue;
73 }
74
75 addrs[con->filters->nr_addrs++] = kmap->unmap_ip(kmap, sym->start);
76 con->filters->addrs = addrs;
77 }
78 naddrs = con->filters->nr_addrs;
79 }
80
81 bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
82 bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
83 bpf_map__set_max_entries(skel->maps.type_filter, ntypes);
84 bpf_map__set_max_entries(skel->maps.addr_filter, naddrs);
85
86 if (lock_contention_bpf__load(skel) < 0) {
87 pr_err("Failed to load lock-contention BPF skeleton\n");
88 return -1;
89 }
90
91 if (target__has_cpu(target)) {
92 u32 cpu;
93 u8 val = 1;
94
95 skel->bss->has_cpu = 1;
96 fd = bpf_map__fd(skel->maps.cpu_filter);
97
98 for (i = 0; i < ncpus; i++) {
99 cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu;
100 bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);
101 }
102 }
103
104 if (target__has_task(target)) {
105 u32 pid;
106 u8 val = 1;
107
108 skel->bss->has_task = 1;
109 fd = bpf_map__fd(skel->maps.task_filter);
110
111 for (i = 0; i < ntasks; i++) {
112 pid = perf_thread_map__pid(evlist->core.threads, i);
113 bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
114 }
115 }
116
117 if (target__none(target) && evlist->workload.pid > 0) {
118 u32 pid = evlist->workload.pid;
119 u8 val = 1;
120
121 skel->bss->has_task = 1;
122 fd = bpf_map__fd(skel->maps.task_filter);
123 bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
124 }
125
126 if (con->filters->nr_types) {
127 u8 val = 1;
128
129 skel->bss->has_type = 1;
130 fd = bpf_map__fd(skel->maps.type_filter);
131
132 for (i = 0; i < con->filters->nr_types; i++)
133 bpf_map_update_elem(fd, &con->filters->types[i], &val, BPF_ANY);
134 }
135
136 if (con->filters->nr_addrs) {
137 u8 val = 1;
138
139 skel->bss->has_addr = 1;
140 fd = bpf_map__fd(skel->maps.addr_filter);
141
142 for (i = 0; i < con->filters->nr_addrs; i++)
143 bpf_map_update_elem(fd, &con->filters->addrs[i], &val, BPF_ANY);
144 }
145
146 /* these don't work well if in the rodata section */
147 skel->bss->stack_skip = con->stack_skip;
148 skel->bss->aggr_mode = con->aggr_mode;
149
150 lock_contention_bpf__attach(skel);
151 return 0;
152}
153
154int lock_contention_start(void)
155{
156 skel->bss->enabled = 1;
157 return 0;
158}
159
160int lock_contention_stop(void)
161{
162 skel->bss->enabled = 0;
163 return 0;
164}
165
166int lock_contention_read(struct lock_contention *con)
167{
168 int fd, stack, task_fd, err = 0;
169 struct contention_key *prev_key, key;
170 struct contention_data data = {};
171 struct lock_stat *st = NULL;
172 struct machine *machine = con->machine;
173 u64 *stack_trace;
174 size_t stack_size = con->max_stack * sizeof(*stack_trace);
175
176 fd = bpf_map__fd(skel->maps.lock_stat);
177 stack = bpf_map__fd(skel->maps.stacks);
178 task_fd = bpf_map__fd(skel->maps.task_data);
179
180 con->lost = skel->bss->lost;
181
182 stack_trace = zalloc(stack_size);
183 if (stack_trace == NULL)
184 return -1;
185
186 if (con->aggr_mode == LOCK_AGGR_TASK) {
187 struct thread *idle = __machine__findnew_thread(machine,
188 /*pid=*/0,
189 /*tid=*/0);
190 thread__set_comm(idle, "swapper", /*timestamp=*/0);
191 }
192
193 /* make sure it loads the kernel map */
194 map__load(maps__first(machine->kmaps));
195
196 prev_key = NULL;
197 while (!bpf_map_get_next_key(fd, prev_key, &key)) {
198 struct map *kmap;
199 struct symbol *sym;
200 int idx = 0;
201 s32 stack_id;
202
203 /* to handle errors in the loop body */
204 err = -1;
205
206 bpf_map_lookup_elem(fd, &key, &data);
207 st = zalloc(sizeof(*st));
208 if (st == NULL)
209 break;
210
211 st->nr_contended = data.count;
212 st->wait_time_total = data.total_time;
213 st->wait_time_max = data.max_time;
214 st->wait_time_min = data.min_time;
215
216 if (data.count)
217 st->avg_wait_time = data.total_time / data.count;
218
219 st->flags = data.flags;
220 st->addr = key.aggr_key;
221
222 if (con->aggr_mode == LOCK_AGGR_TASK) {
223 struct contention_task_data task;
224 struct thread *t;
225 int pid = key.aggr_key;
226
227 /* do not update idle comm which contains CPU number */
228 if (st->addr) {
229 bpf_map_lookup_elem(task_fd, &pid, &task);
230 t = __machine__findnew_thread(machine, /*pid=*/-1, pid);
231 thread__set_comm(t, task.comm, /*timestamp=*/0);
232 }
233 goto next;
234 }
235
236 if (con->aggr_mode == LOCK_AGGR_ADDR) {
237 sym = machine__find_kernel_symbol(machine, st->addr, &kmap);
238 if (sym)
239 st->name = strdup(sym->name);
240 goto next;
241 }
242
243 stack_id = key.aggr_key;
244 bpf_map_lookup_elem(stack, &stack_id, stack_trace);
245
246 /* skip lock internal functions */
247 while (machine__is_lock_function(machine, stack_trace[idx]) &&
248 idx < con->max_stack - 1)
249 idx++;
250
251 st->addr = stack_trace[idx];
252 sym = machine__find_kernel_symbol(machine, st->addr, &kmap);
253
254 if (sym) {
255 unsigned long offset;
256 int ret = 0;
257
258 offset = kmap->map_ip(kmap, st->addr) - sym->start;
259
260 if (offset)
261 ret = asprintf(&st->name, "%s+%#lx", sym->name, offset);
262 else
263 st->name = strdup(sym->name);
264
265 if (ret < 0 || st->name == NULL)
266 break;
267 } else if (asprintf(&st->name, "%#lx", (unsigned long)st->addr) < 0) {
268 break;
269 }
270
271 if (verbose > 0) {
272 st->callstack = memdup(stack_trace, stack_size);
273 if (st->callstack == NULL)
274 break;
275 }
276next:
277 hlist_add_head(&st->hash_entry, con->result);
278 prev_key = &key;
279
280 /* we're fine now, reset the values */
281 st = NULL;
282 err = 0;
283 }
284
285 free(stack_trace);
286 if (st) {
287 free(st->name);
288 free(st);
289 }
290
291 return err;
292}
293
294int lock_contention_finish(void)
295{
296 if (skel) {
297 skel->bss->enabled = 0;
298 lock_contention_bpf__destroy(skel);
299 }
300
301 return 0;
302}