perf lock contention: Handle slab objects in -L/--lock-filter option

This is to filter lock contention from specific slab objects only.
Like in the lock symbol output, we can use '&' prefix to filter slab
object names.

  root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -abl sleep 1
   contended   total wait     max wait     avg wait            address   symbol

           3     14.99 us     14.44 us      5.00 us   ffffffff851c0940   pack_mutex (mutex)
           2      2.75 us      2.56 us      1.38 us   ffff98d7031fb498   &task_struct (mutex)
           4      1.42 us       557 ns       355 ns   ffff98d706311400   &kmalloc-cg-512 (mutex)
           2       953 ns       714 ns       476 ns   ffffffff851c3620   delayed_uprobe_lock (mutex)
           1       929 ns       929 ns       929 ns   ffff98d7031fb538   &task_struct (mutex)
           3       561 ns       210 ns       187 ns   ffffffff84a8b3a0   text_mutex (mutex)
           1       479 ns       479 ns       479 ns   ffffffff851b4cf8   tracepoint_srcu_srcu_usage (mutex)
           2       320 ns       195 ns       160 ns   ffffffff851cf840   pcpu_alloc_mutex (mutex)
           1       212 ns       212 ns       212 ns   ffff98d7031784d8   &signal_cache (mutex)
           1       177 ns       177 ns       177 ns   ffffffff851b4c28   tracepoint_srcu_srcu_usage (mutex)

With the filter, it can show contentions from the task_struct only.

  root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -abl -L '&task_struct' sleep 1
   contended   total wait     max wait     avg wait            address   symbol

           2      1.97 us      1.71 us       987 ns   ffff98d7032fd658   &task_struct (mutex)
           1      1.20 us      1.20 us      1.20 us   ffff98d7032fd6f8   &task_struct (mutex)

It can work with other aggregation mode:

  root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -ab -L '&task_struct' sleep 1
   contended   total wait     max wait     avg wait         type   caller

           1     25.10 us     25.10 us     25.10 us        mutex   perf_event_exit_task+0x39
           1     21.60 us     21.60 us     21.60 us        mutex   futex_exit_release+0x21
           1      5.56 us      5.56 us      5.56 us        mutex   futex_exec_release+0x21

Committer testing:

  root@number:~# perf lock con -abl sleep 1
   contended   total wait     max wait     avg wait            address   symbol

           1     20.80 us     20.80 us     20.80 us   ffff9d417fbd65d0    (spinlock)
           8     12.85 us      2.41 us      1.61 us   ffff9d415eeb6a40   rq_lock (spinlock)
           1      2.55 us      2.55 us      2.55 us   ffff9d415f636a40   rq_lock (spinlock)
           7      1.92 us       840 ns       274 ns   ffff9d39c2cbc8c4    (spinlock)
           1      1.23 us      1.23 us      1.23 us   ffff9d415fb36a40   rq_lock (spinlock)
           2       928 ns       738 ns       464 ns   ffff9d39c1fa6660   &kmalloc-rnd-14-192 (rwlock)
           4       788 ns       252 ns       197 ns   ffffffffb8608a80   jiffies_lock (spinlock)
           1       304 ns       304 ns       304 ns   ffff9d39c2c979c4    (spinlock)
           1       216 ns       216 ns       216 ns   ffff9d3a0225c660   &kmalloc-rnd-14-192 (rwlock)
           1        89 ns        89 ns        89 ns   ffff9d3a0adbf3e0   &kmalloc-rnd-14-192 (rwlock)
           1        61 ns        61 ns        61 ns   ffff9d415f9b6a40   rq_lock (spinlock)
  root@number:~# uname -r
  6.13.0-rc2
  root@number:~#

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/r/20241220060009.507297-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index d9f3477d2b02..208c482daa56 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -1539,6 +1539,12 @@ static void lock_filter_finish(void)
 
 	zfree(&filters.cgrps);
 	filters.nr_cgrps = 0;
+
+	for (int i = 0; i < filters.nr_slabs; i++)
+		free(filters.slabs[i]);
+
+	zfree(&filters.slabs);
+	filters.nr_slabs = 0;
 }
 
 static void sort_contention_result(void)
@@ -2305,6 +2311,27 @@ static bool add_lock_sym(char *name)
 	return true;
 }
 
+static bool add_lock_slab(char *name)
+{
+	char **tmp;
+	char *sym = strdup(name);
+
+	if (sym == NULL) {
+		pr_err("Memory allocation failure\n");
+		return false;
+	}
+
+	tmp = realloc(filters.slabs, (filters.nr_slabs + 1) * sizeof(*filters.slabs));
+	if (tmp == NULL) {
+		pr_err("Memory allocation failure\n");
+		return false;
+	}
+
+	tmp[filters.nr_slabs++] = sym;
+	filters.slabs = tmp;
+	return true;
+}
+
 static int parse_lock_addr(const struct option *opt __maybe_unused, const char *str,
 			   int unset __maybe_unused)
 {
@@ -2328,6 +2355,14 @@ static int parse_lock_addr(const struct option *opt __maybe_unused, const char *
 			continue;
 		}
 
+		if (*tok == '&') {
+			if (!add_lock_slab(tok + 1)) {
+				ret = -1;
+				break;
+			}
+			continue;
+		}
+
 		/*
 		 * At this moment, we don't have kernel symbols.  Save the symbols
 		 * in a separate list and resolve them to addresses later.