perf callchain: Use pthread keys for tls callchain_cursor

Pthread keys are more portable than __thread and allow the association
of a destructor with the key. Use the destructor to clean up TLS
callchain cursors to aid understanding memory leaks.

Committer notes:

Had to fixup a series of unconverted places and also check for the
return of get_tls_callchain_cursor() as it may fail and return NULL.

In that unlikely case we now either print something to a file, if the
caller was expecting to print a callchain, or return an error code to
state that resolving the callchain isn't possible.

In some cases this was made easier because thread__resolve_callchain()
already can fail for other reasons, so this new one (cursor == NULL) can
be added and the callers don't have to explicitely check for this new
condition.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ali Saidi <alisaidi@amazon.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Brian Robbins <brianrob@linux.microsoft.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: Fangrui Song <maskray@google.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Wenyu Liu <liuwenyu7@huawei.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Ye Xingchen <ye.xingchen@zte.com.cn>
Cc: Yuan Can <yuancan@huawei.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230608232823.4027869-25-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index cd79068200e5..c9ddf73689cd 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2111,7 +2111,7 @@ static void timehist_print_sample(struct perf_sched *sched,
 			    EVSEL__PRINT_SYM | EVSEL__PRINT_ONELINE |
 			    EVSEL__PRINT_CALLCHAIN_ARROW |
 			    EVSEL__PRINT_SKIP_IGNORED,
-			    &callchain_cursor, symbol_conf.bt_stop_list,  stdout);
+			    get_tls_callchain_cursor(), symbol_conf.bt_stop_list,  stdout);
 
 out:
 	printf("\n");
@@ -2196,7 +2196,7 @@ static void save_task_callchain(struct perf_sched *sched,
 				struct evsel *evsel,
 				struct machine *machine)
 {
-	struct callchain_cursor *cursor = &callchain_cursor;
+	struct callchain_cursor *cursor;
 	struct thread *thread;
 
 	/* want main thread for process - has maps */
@@ -2209,6 +2209,8 @@ static void save_task_callchain(struct perf_sched *sched,
 	if (!sched->show_callchain || sample->callchain == NULL)
 		return;
 
+	cursor = get_tls_callchain_cursor();
+
 	if (thread__resolve_callchain(thread, cursor, evsel, sample,
 				      NULL, NULL, sched->max_stack + 2) != 0) {
 		if (verbose > 0)
@@ -2338,10 +2340,16 @@ static void save_idle_callchain(struct perf_sched *sched,
 				struct idle_thread_runtime *itr,
 				struct perf_sample *sample)
 {
+	struct callchain_cursor *cursor;
+
 	if (!sched->show_callchain || sample->callchain == NULL)
 		return;
 
-	callchain_cursor__copy(&itr->cursor, &callchain_cursor);
+	cursor = get_tls_callchain_cursor();
+	if (cursor == NULL)
+		return;
+
+	callchain_cursor__copy(&itr->cursor, cursor);
 }
 
 static struct thread *timehist_get_thread(struct perf_sched *sched,