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Date: Tue, 13 Feb 2024 22:37:05 -0800
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Subject: [PATCH v1 3/6] perf machine: Move fprintf to for_each loop and a callback
From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, 
	Arnaldo Carvalho de Melo <acme@kernel.org>, Namhyung Kim <namhyung@kernel.org>, 
	Mark Rutland <mark.rutland@arm.com>, 
	Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@kernel.org>, 
	Ian Rogers <irogers@google.com>, Adrian Hunter <adrian.hunter@intel.com>, 
	Oliver Upton <oliver.upton@linux.dev>, Yang Jihong <yangjihong1@huawei.com>, 
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, 
	bpf@vger.kernel.org
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Avoid exposing the threads data structure by switching to the callback
machine__for_each_thread approach. machine__fprintf is only used in
tests and verbose >3 output so don't turn to list and sort. Add
machine__threads_nr to be refactored later.

Note, all existing *_fprintf routines ignore fprintf errors.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/machine.c | 43 ++++++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 7872ce92c9fc..e072b2115b64 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1113,29 +1113,40 @@ size_t machine__fprintf_vmlinux_path(struct machine *machine, FILE *fp)
 	return printed;
 }
 
-size_t machine__fprintf(struct machine *machine, FILE *fp)
+struct machine_fprintf_cb_args {
+	FILE *fp;
+	size_t printed;
+};
+
+static int machine_fprintf_cb(struct thread *thread, void *data)
 {
-	struct rb_node *nd;
-	size_t ret;
-	int i;
+	struct machine_fprintf_cb_args *args = data;
 
-	for (i = 0; i < THREADS__TABLE_SIZE; i++) {
-		struct threads *threads = &machine->threads[i];
+	/* TODO: handle fprintf errors. */
+	args->printed += thread__fprintf(thread, args->fp);
+	return 0;
+}
 
-		down_read(&threads->lock);
+static size_t machine__threads_nr(const struct machine *machine)
+{
+	size_t nr = 0;
 
-		ret = fprintf(fp, "Threads: %u\n", threads->nr);
+	for (int i = 0; i < THREADS__TABLE_SIZE; i++)
+		nr += machine->threads[i].nr;
 
-		for (nd = rb_first_cached(&threads->entries); nd;
-		     nd = rb_next(nd)) {
-			struct thread *pos = rb_entry(nd, struct thread_rb_node, rb_node)->thread;
+	return nr;
+}
 
-			ret += thread__fprintf(pos, fp);
-		}
+size_t machine__fprintf(struct machine *machine, FILE *fp)
+{
+	struct machine_fprintf_cb_args args = {
+		.fp = fp,
+		.printed = 0,
+	};
+	size_t ret = fprintf(fp, "Threads: %zu\n", machine__threads_nr(machine));
 
-		up_read(&threads->lock);
-	}
-	return ret;
+	machine__for_each_thread(machine, machine_fprintf_cb, &args);
+	return ret + args.printed;
 }
 
 static struct dso *machine__get_kernel(struct machine *machine)
-- 
2.43.0.687.g38aa6559b0-goog