[LTP] [PATCH 1/2] lib: add tst_request_hugepages

[Li Wang]

Note: more and more tests need to configure hugepage before testing, so
this is a start to add some useful hugetlb functions in global library
for the whole LTP.

Signed-off-by: Li Wang <liwang@redhat.com>
---
 include/tst_hugepage.h | 19 +++++++++++++++++++
 include/tst_test.h     |  1 +
 lib/tst_hugepage.c     | 43 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+)
 create mode 100644 include/tst_hugepage.h
 create mode 100644 lib/tst_hugepage.c

diff --git a/include/tst_hugepage.h b/include/tst_hugepage.h
new file mode 100644
index 000000000..e06705bd0
--- /dev/null
+++ b/include/tst_hugepage.h
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 Red Hat, Inc.
+ */
+
+#ifndef TST_HUGEPAGE__
+#define TST_HUGEPAGE__
+
+/*
+ * Try to request the specified number of huge pages from system.
+ *
+ * Note: this depend on the status of system memory fragmentation.
+ *       0 - reserve fail
+ *       1 - reserve success
+ */
+int tst_request_hugepages(long hpages);
+
+#endif /* TST_HUGEPAGE_H */
+
diff --git a/include/tst_test.h b/include/tst_test.h
index 21c7dfbdb..7ec1ab865 100644
--- a/include/tst_test.h
+++ b/include/tst_test.h
@@ -37,6 +37,7 @@
 #include "tst_coredump.h"
 #include "tst_buffers.h"
 #include "tst_capability.h"
+#include "tst_hugepage.h"
 
 /*
  * Reports testcase result.
diff --git a/lib/tst_hugepage.c b/lib/tst_hugepage.c
new file mode 100644
index 000000000..00cf90843
--- /dev/null
+++ b/lib/tst_hugepage.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 Red Hat, Inc.
+ */
+
+#define TST_NO_DEFAULT_MAIN
+
+#include "tst_test.h"
+#include "tst_hugepage.h"
+
+int tst_request_hugepages(long hpages)
+{
+	int val;
+	long mem_avail, max_hpages;
+
+	if (FILE_LINES_SCANF("/proc/meminfo",
+				"MemAvailable: %ld", &mem_avail)) {
+		/*
+		 * Dropping caches and using "MemFree:" on kernel
+		 * that doesn't have "MemAvailable:" in Meminfo
+		 */
+		tst_res(TINFO, "MemAvailable: not found in /proc/meminfo");
+
+		SAFE_FILE_PRINTF("/proc/sys/vm/drop_caches", "3");
+		mem_avail = SAFE_READ_MEMINFO("MemFree:");
+	}
+
+	max_hpages = mem_avail / SAFE_READ_MEMINFO("Hugepagesize:");
+
+	if (hpages > max_hpages) {
+		tst_res(TINFO, "Request %ld hugepages failed, memory too fragmented? "
+				"The max hugepage available count %ld",
+				hpages, max_hpages);
+		return 0;
+	}
+
+	SAFE_FILE_PRINTF("/proc/sys/vm/nr_hugepages", "%ld", hpages);
+	SAFE_FILE_SCANF("/proc/sys/vm/nr_hugepages", "%d", &val);
+	if (val != hpages)
+		tst_brk(TBROK, "nr_hugepages = %d, but expect %ld", val, hpages);
+
+	return 1;
+}
-- 
2.20.1