1 files changed, 63 insertions, 28 deletions

diff --git a/tools/testing/selftests/mm/compaction_test.c b/tools/testing/selftests/mm/compaction_test.c
index 533999b6c284..e140558e6f53 100644
--- a/tools/testing/selftests/mm/compaction_test.c
+++ b/tools/testing/selftests/mm/compaction_test.c
@@ -82,12 +82,16 @@ int prereq(void)
 	return -1;
 }
 
-int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
+int check_compaction(unsigned long mem_free, unsigned long hugepage_size,
+		     unsigned long initial_nr_hugepages)
 {
+	unsigned long nr_hugepages_ul;
 	int fd, ret = -1;
 	int compaction_index = 0;
-	char initial_nr_hugepages[10] = {0};
-	char nr_hugepages[10] = {0};
+	char nr_hugepages[20] = {0};
+	char init_nr_hugepages[20] = {0};
+
+	sprintf(init_nr_hugepages, "%lu", initial_nr_hugepages);
 
 	/* We want to test with 80% of available memory. Else, OOM killer comes
 	   in to play */
@@ -101,21 +105,6 @@ int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
 		goto out;
 	}
 
-	if (read(fd, initial_nr_hugepages, sizeof(initial_nr_hugepages)) <= 0) {
-		ksft_print_msg("Failed to read from /proc/sys/vm/nr_hugepages: %s\n",
-			       strerror(errno));
-		goto close_fd;
-	}
-
-	/* Start with the initial condition of 0 huge pages*/
-	if (write(fd, "0", sizeof(char)) != sizeof(char)) {
-		ksft_print_msg("Failed to write 0 to /proc/sys/vm/nr_hugepages: %s\n",
-			       strerror(errno));
-		goto close_fd;
-	}
-
-	lseek(fd, 0, SEEK_SET);
-
 	/* Request a large number of huge pages. The Kernel will allocate
 	   as much as it can */
 	if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) {
@@ -134,22 +123,27 @@ int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
 
 	/* We should have been able to request at least 1/3 rd of the memory in
 	   huge pages */
-	compaction_index = mem_free/(atoi(nr_hugepages) * hugepage_size);
+	nr_hugepages_ul = strtoul(nr_hugepages, NULL, 10);
+	if (!nr_hugepages_ul) {
+		ksft_print_msg("ERROR: No memory is available as huge pages\n");
+		goto close_fd;
+	}
+	compaction_index = mem_free/(nr_hugepages_ul * hugepage_size);
 
 	lseek(fd, 0, SEEK_SET);
 
-	if (write(fd, initial_nr_hugepages, strlen(initial_nr_hugepages))
-	    != strlen(initial_nr_hugepages)) {
+	if (write(fd, init_nr_hugepages, strlen(init_nr_hugepages))
+	    != strlen(init_nr_hugepages)) {
 		ksft_print_msg("Failed to write value to /proc/sys/vm/nr_hugepages: %s\n",
 			       strerror(errno));
 		goto close_fd;
 	}
 
-	ksft_print_msg("Number of huge pages allocated = %d\n",
-		       atoi(nr_hugepages));
+	ksft_print_msg("Number of huge pages allocated = %lu\n",
+		       nr_hugepages_ul);
 
 	if (compaction_index > 3) {
-		ksft_print_msg("ERROR: Less that 1/%d of memory is available\n"
+		ksft_print_msg("ERROR: Less than 1/%d of memory is available\n"
 			       "as huge pages\n", compaction_index);
 		goto close_fd;
 	}
@@ -163,6 +157,41 @@ int check_compaction(unsigned long mem_free, unsigned int hugepage_size)
 	return ret;
 }
 
+int set_zero_hugepages(unsigned long *initial_nr_hugepages)
+{
+	int fd, ret = -1;
+	char nr_hugepages[20] = {0};
+
+	fd = open("/proc/sys/vm/nr_hugepages", O_RDWR | O_NONBLOCK);
+	if (fd < 0) {
+		ksft_print_msg("Failed to open /proc/sys/vm/nr_hugepages: %s\n",
+			       strerror(errno));
+		goto out;
+	}
+	if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) {
+		ksft_print_msg("Failed to read from /proc/sys/vm/nr_hugepages: %s\n",
+			       strerror(errno));
+		goto close_fd;
+	}
+
+	lseek(fd, 0, SEEK_SET);
+
+	/* Start with the initial condition of 0 huge pages */
+	if (write(fd, "0", sizeof(char)) != sizeof(char)) {
+		ksft_print_msg("Failed to write 0 to /proc/sys/vm/nr_hugepages: %s\n",
+			       strerror(errno));
+		goto close_fd;
+	}
+
+	*initial_nr_hugepages = strtoul(nr_hugepages, NULL, 10);
+	ret = 0;
+
+ close_fd:
+	close(fd);
+
+ out:
+	return ret;
+}
 
 int main(int argc, char **argv)
 {
@@ -173,14 +202,19 @@ int main(int argc, char **argv)
 	unsigned long mem_free = 0;
 	unsigned long hugepage_size = 0;
 	long mem_fragmentable_MB = 0;
+	unsigned long initial_nr_hugepages;
 
 	ksft_print_header();
 
 	if (prereq() || geteuid())
-		return ksft_exit_skip("Prerequisites unsatisfied\n");
+		ksft_exit_skip("Prerequisites unsatisfied\n");
 
 	ksft_set_plan(1);
 
+	/* Start the test without hugepages reducing mem_free */
+	if (set_zero_hugepages(&initial_nr_hugepages))
+		ksft_exit_fail();
+
 	lim.rlim_cur = RLIM_INFINITY;
 	lim.rlim_max = RLIM_INFINITY;
 	if (setrlimit(RLIMIT_MEMLOCK, &lim))
@@ -224,8 +258,9 @@ int main(int argc, char **argv)
 		entry = entry->next;
 	}
 
-	if (check_compaction(mem_free, hugepage_size) == 0)
-		return ksft_exit_pass();
+	if (check_compaction(mem_free, hugepage_size,
+			     initial_nr_hugepages) == 0)
+		ksft_exit_pass();
 
-	return ksft_exit_fail();
+	ksft_exit_fail();
 }