perf lock contention: Support lock addr/name filtering for BPF

Likewise, add addr_filter BPF hash map and check it with the lock
address.

$ sudo ./perf lock con -ab -L tasklist_lock -- ./perf bench sched messaging
# Running 'sched/messaging' benchmark:
# 20 sender and receiver processes per group
# 10 groups == 400 processes run

Total time: 0.169 [sec]
contended total wait max wait avg wait type caller

18 174.09 us 25.31 us 9.67 us rwlock:W do_exit+0x36d
5 32.34 us 10.87 us 6.47 us rwlock:R do_wait+0x8b
4 15.41 us 4.73 us 3.85 us rwlock:W release_task+0x6e

Signed-off-by: Namhyung Kim <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Blake Jones <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Song Liu <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/bpf_lock_contention.c

···
 int lock_contention_prepare(struct lock_contention *con)
 {
 	int i, fd;
-	int ncpus = 1, ntasks = 1, ntypes = 1;
+	int ncpus = 1, ntasks = 1, ntypes = 1, naddrs = 1;
 	struct evlist *evlist = con->evlist;
 	struct target *target = con->target;
 
···
 	if (con->filters->nr_types)
 		ntypes = con->filters->nr_types;
 
+	/* resolve lock name filters to addr */
+	if (con->filters->nr_syms) {
+		struct symbol *sym;
+		struct map *kmap;
+		unsigned long *addrs;
+
+		for (i = 0; i < con->filters->nr_syms; i++) {
+			sym = machine__find_kernel_symbol_by_name(con->machine,
+								  con->filters->syms[i],
+								  &kmap);
+			if (sym == NULL) {
+				pr_warning("ignore unknown symbol: %s\n",
+					   con->filters->syms[i]);
+				continue;
+			}
+
+			addrs = realloc(con->filters->addrs,
+					(con->filters->nr_addrs + 1) * sizeof(*addrs));
+			if (addrs == NULL) {
+				pr_warning("memory allocation failure\n");
+				continue;
+			}
+
+			addrs[con->filters->nr_addrs++] = kmap->unmap_ip(kmap, sym->start);
+			con->filters->addrs = addrs;
+		}
+		naddrs = con->filters->nr_addrs;
+	}
+
 	bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
 	bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
 	bpf_map__set_max_entries(skel->maps.type_filter, ntypes);
+	bpf_map__set_max_entries(skel->maps.addr_filter, naddrs);
 
 	if (lock_contention_bpf__load(skel) < 0) {
 		pr_err("Failed to load lock-contention BPF skeleton\n");
···
 
 		for (i = 0; i < con->filters->nr_types; i++)
 			bpf_map_update_elem(fd, &con->filters->types[i], &val, BPF_ANY);
+	}
+
+	if (con->filters->nr_addrs) {
+		u8 val = 1;
+
+		skel->bss->has_addr = 1;
+		fd = bpf_map__fd(skel->maps.addr_filter);
+
+		for (i = 0; i < con->filters->nr_addrs; i++)
+			bpf_map_update_elem(fd, &con->filters->addrs[i], &val, BPF_ANY);
 	}
 
 	/* these don't work well if in the rodata section */

tools/perf/util/bpf_skel/lock_contention.bpf.c

···
 	__uint(max_entries, 1);
 } type_filter SEC(".maps");
 
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(key_size, sizeof(__u64));
+	__uint(value_size, sizeof(__u8));
+	__uint(max_entries, 1);
+} addr_filter SEC(".maps");
+
 /* control flags */
 int enabled;
 int has_cpu;
 int has_task;
 int has_type;
+int has_addr;
 int stack_skip;
 
 /* determine the key of lock stat */
···
 		__u32 flags = (__u32)ctx[1];
 
 		ok = bpf_map_lookup_elem(&type_filter, &flags);
+		if (!ok)
+			return 0;
+	}
+
+	if (has_addr) {
+		__u8 *ok;
+		__u64 addr = ctx[0];
+
+		ok = bpf_map_lookup_elem(&addr_filter, &addr);
 		if (!ok)
 			return 0;
 	}