lib/tst_numa: Add library for NUMA related syscalls

The library implements a nodemap, which is a map of nodes (array)
containing node ids for a subset of system nodes. Currently nodes can be
filtered based on memory requirements, which is needed for testing
memory related NUMA syscalls such as set_mempolicy() and membind() where
we usually need at least two memory nodes with free memory.

It also implements counters, so that we can precisely count, for a given
memory range, how much memory was allocated on each node in the map and
a few simple functions for mapping, faulting and unmapping memory.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
CC: Vlastimil Babka <vbabka@suse.cz>
CC: Michal Hocko <mhocko@kernel.org>
CC: Jan Stancek <jstancek@redhat.com>
Acked-by: Jan Stancek <jstancek@redhat.com>

1 files changed, 112 insertions, 0 deletions

diff --git a/include/tst_numa.h b/include/tst_numa.h
new file mode 100644
index 000000000..a4cd1be37
--- /dev/null
+++ b/include/tst_numa.h
@@ -0,0 +1,112 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Copyright (c) 2018 Cyril Hrubis <chrubis@suse.cz>
+ */
+
+#ifndef TST_NUMA_H__
+#define TST_NUMA_H__
+
+/**
+ * Numa nodemap.
+ */
+struct tst_nodemap {
+        /** Number of nodes in map */
+	unsigned int cnt;
+	/** Page allocation counters */
+	unsigned int *counters;
+	/** Array of numa ids */
+	unsigned int map[];
+};
+
+/**
+ * Clears numa counters. The counters are lazy-allocated on first call of this function.
+ *
+ * @nodes Numa nodemap.
+ */
+void tst_nodemap_reset_counters(struct tst_nodemap *nodes);
+
+/**
+ * Prints pages allocated per each node.
+ *
+ * @nodes Numa nodemap.
+ */
+void tst_nodemap_print_counters(struct tst_nodemap *nodes);
+
+/**
+ * Returns a name for a mempolicy/mbind mode.
+ *
+ * @mode Numa mempolicy mode.
+ */
+const char *tst_numa_mode_name(int mode);
+
+/**
+ * Maps pages into memory, if path is NULL the mapping is anonymous otherwise is backed by the file.
+ *
+ * @path Path to a file, if not NULL mapping is file based.
+ * @size Mapping size.
+ */
+void *tst_numa_map(const char *path, size_t size);
+
+/*
+ * Writes to memory in order to get the pages faulted.
+ *
+ * @ptr Start of the mapping.
+ * @size Size of the mapping.
+ */
+static inline void tst_numa_fault(void *ptr, size_t size)
+{
+	memset(ptr, 'a', size);
+}
+
+/*
+ * Frees the memory.
+ *
+ * @ptr Start of the mapping.
+ * @size Size of the mapping.
+ */
+static inline void tst_numa_unmap(void *ptr, size_t size)
+{
+	SAFE_MUNMAP(ptr, size);
+}
+
+/**
+ * Check on which numa node resides each page of the mapping starting at ptr
+ * and continuing pages long and increases nodemap counters accordingly.
+ *
+ * @nodes Nodemap with initialized counters.
+ * @ptr   Pointer to start of a mapping.
+ * @size  Size of the mapping.
+ */
+void tst_nodemap_count_pages(struct tst_nodemap *nodes, void *ptr, size_t size);
+
+/**
+ * Frees nodemap.
+ *
+ * @nodes Numa nodemap to be freed.
+ */
+void tst_nodemap_free(struct tst_nodemap *nodes);
+
+/**
+ * Bitflags for tst_get_nodemap() function.
+ */
+enum tst_numa_types {
+	TST_NUMA_ANY = 0x00,
+	TST_NUMA_MEM = 0x01,
+};
+
+/**
+ * Allocates and returns numa node map, which is an array of numa nodes which
+ * contain desired resources e.g. memory.
+ *
+ * @type       Bitflags of enum tst_numa_types specifying desired resources.
+ * @min_mem_kb Minimal free RAM on memory nodes, if given node has less than
+ *             requested amount of free+buffers memory it's not included in
+ *             the resulting list of nodes.
+ *
+ * @return On success returns allocated and initialized struct tst_nodemap which contains
+ *         array of numa node ids that contains desired resources.
+ */
+struct tst_nodemap *tst_get_nodemap(int type, size_t min_mem_kb);
+
+#endif /* TST_NUMA_H__ */