Add option to fetch system thread name on each prof sample

test/unit/mallctl.c

@@ -192,6 +192,7 @@ TEST_BEGIN(test_mallctl_opt) {
 	TEST_MALLCTL_OPT(bool, prof_final, prof);
 	TEST_MALLCTL_OPT(bool, prof_leak, prof);
 	TEST_MALLCTL_OPT(ssize_t, prof_recent_alloc_max, prof);
+	TEST_MALLCTL_OPT(bool, prof_experimental_use_sys_thread_name, prof);
 
 #undef TEST_MALLCTL_OPT
 }

test/unit/prof_use_sys_thread_name.c

@@ -0,0 +1,75 @@
+#include "test/jemalloc_test.h"
+
+static const char *test_thread_name = "test_name";
+
+static int
+test_prof_read_sys_thread_name_error(char *buf, size_t limit) {
+	return ENOSYS;
+}
+
+static int
+test_prof_read_sys_thread_name(char *buf, size_t limit) {
+	assert(strlen(test_thread_name) < limit);
+	strncpy(buf, test_thread_name, limit);
+	return 0;
+}
+
+static int
+test_prof_read_sys_thread_name_clear(char *buf, size_t limit) {
+	assert(limit > 0);
+	buf[0] = '\0';
+	return 0;
+}
+
+TEST_BEGIN(test_prof_experimental_use_sys_thread_name) {
+	test_skip_if(!config_prof);
+
+	bool oldval;
+	size_t sz = sizeof(oldval);
+	assert_d_eq(mallctl("opt.prof_experimental_use_sys_thread_name",
+	    &oldval, &sz, NULL,	0), 0, "mallctl failed");
+	assert_true(oldval, "option was not set correctly");
+
+	const char *thread_name;
+	sz = sizeof(thread_name);
+	assert_d_eq(mallctl("thread.prof.name", &thread_name, &sz, NULL, 0), 0,
+	    "mallctl read for thread name should not fail");
+	expect_str_eq(thread_name, "", "Initial thread name should be empty");
+
+	thread_name = test_thread_name;
+	assert_d_eq(mallctl("thread.prof.name", NULL, NULL, &thread_name, sz),
+	    ENOENT, "mallctl write for thread name should fail");
+	assert_ptr_eq(thread_name, test_thread_name,
+	    "Thread name should not be touched");
+
+	prof_read_sys_thread_name = test_prof_read_sys_thread_name_error;
+	void *p = malloc(1);
+	free(p);
+	assert_d_eq(mallctl("thread.prof.name", &thread_name, &sz, NULL, 0), 0,
+	    "mallctl read for thread name should not fail");
+	assert_str_eq(thread_name, "",
+	    "Thread name should stay the same if the system call fails");
+
+	prof_read_sys_thread_name = test_prof_read_sys_thread_name;
+	p = malloc(1);
+	free(p);
+	assert_d_eq(mallctl("thread.prof.name", &thread_name, &sz, NULL, 0), 0,
+	    "mallctl read for thread name should not fail");
+	assert_str_eq(thread_name, test_thread_name,
+	    "Thread name should be changed if the system call succeeds");
+
+	prof_read_sys_thread_name = test_prof_read_sys_thread_name_clear;
+	p = malloc(1);
+	free(p);
+	assert_d_eq(mallctl("thread.prof.name", &thread_name, &sz, NULL, 0), 0,
+	    "mallctl read for thread name should not fail");
+	expect_str_eq(thread_name, "", "Thread name should be updated if the "
+	    "system call returns a different name");
+}
+TEST_END
+
+int
+main(void) {
+	return test(
+	    test_prof_experimental_use_sys_thread_name);
+}

test/unit/prof_use_sys_thread_name.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+if [ "x${enable_prof}" = "x1" ] ; then
+  export MALLOC_CONF="prof:true,lg_prof_sample:0,prof_experimental_use_sys_thread_name:true"
+fi