From d42f467a923dfc09309acb7a83b42e3285fbd8f4 Mon Sep 17 00:00:00 2001
Message-Id: <d42f467a923dfc09309acb7a83b42e3285fbd8f4.1566225007.git.aquini@redhat.com>
From: Sandipan Das <sandipan@linux.ibm.com>
Date: Thu, 15 Aug 2019 13:08:28 +0530
Subject: [RHEL7 PATCH 01/31] tests: Add utility to check for a minimum number
 of online cpus

This adds a test utility to check if a minimum number (N)
of online cpus are available. If available, this will also
provide a list of the first N online cpus.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Rafael Aquini <aquini@redhat.com>
---
 tests/hugetests.h |  1 +
 tests/testutils.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/tests/hugetests.h b/tests/hugetests.h
index 8b1d8d9..e3179e6 100644
--- a/tests/hugetests.h
+++ b/tests/hugetests.h
@@ -43,6 +43,7 @@ extern char *test_name;
 void check_free_huge_pages(int nr_pages_needed);
 void check_must_be_root(void);
 void check_hugetlb_shm_group(void);
+void check_online_cpus(int[], int);
 void test_init(int argc, char *argv[]);
 int test_addr_huge(void *p);
 unsigned long long get_mapping_page_size(void *p);
diff --git a/tests/testutils.c b/tests/testutils.c
index 6298370..2b47547 100644
--- a/tests/testutils.c
+++ b/tests/testutils.c
@@ -33,6 +33,8 @@
 #include <sys/ipc.h>
 #include <sys/shm.h>
 #include <sys/stat.h>
+#include <sys/sysinfo.h>
+#include <sys/types.h>
 #include <sys/mman.h>
 #include <fcntl.h>
 
@@ -80,6 +82,52 @@ void check_hugetlb_shm_group(void)
 		CONFIG("Do not have permission to use SHM_HUGETLB");
 }
 
+#define SYSFS_CPU_ONLINE_FMT	"/sys/devices/system/cpu/cpu%d/online"
+
+void check_online_cpus(int online_cpus[], int nr_cpus_needed)
+{
+	char cpu_state, path_buf[64];
+	int total_cpus, cpu_idx, fd, ret, i;
+
+	total_cpus = get_nprocs_conf();
+	cpu_idx = 0;
+
+	if (get_nprocs() < nr_cpus_needed)
+		CONFIG("Atleast online %d cpus are required", nr_cpus_needed);
+
+	for (i = 0; i < total_cpus && cpu_idx < nr_cpus_needed; i++) {
+		errno = 0;
+		sprintf(path_buf, SYSFS_CPU_ONLINE_FMT, i);
+		fd = open(path_buf, O_RDONLY);
+		if (fd < 0) {
+			/* If 'online' is absent, the cpu cannot be offlined */
+			if (errno == ENOENT) {
+				online_cpus[cpu_idx] = i;
+				cpu_idx++;
+				continue;
+			} else {
+				FAIL("Unable to open %s: %s", path_buf,
+				     strerror(errno));
+			}
+		}
+
+		ret = read(fd, &cpu_state, 1);
+		if (ret < 1)
+			FAIL("Unable to read %s: %s", path_buf,
+			     strerror(errno));
+
+		if (cpu_state == '1') {
+			online_cpus[cpu_idx] = i;
+			cpu_idx++;
+		}
+
+		close(fd);
+	}
+
+	if (cpu_idx < nr_cpus_needed)
+		CONFIG("Atleast %d online cpus were not found", nr_cpus_needed);
+}
+
 void  __attribute__((weak)) cleanup(void)
 {
 }
-- 
1.8.3.1