[bpf-next,2/2] selftests/bpf: test map pressure

Commit Message

Anton Protopopov May 31, 2023, 11:05 a.m. UTC

Add a new map test, map_pressure.c, which is checking the correctness of
map's raw_pressure values.

For maps for which the pressure equals to the current number of elements (only
such maps support the raw_pressure at the moment) the test upserts a number of
elements, checks the correctness of the pressure value, then deletes all the
elements and checks again that the pressure dropped down to zero.

The following map types are tested:

    * BPF_MAP_TYPE_HASH, BPF_F_NO_PREALLOC
    * BPF_MAP_TYPE_PERCPU_HASH, BPF_F_NO_PREALLOC
    * BPF_MAP_TYPE_HASH,
    * BPF_MAP_TYPE_PERCPU_HASH,
    * BPF_MAP_TYPE_LRU_HASH
    * BPF_MAP_TYPE_LRU_PERCPU_HASH
    * BPF_MAP_TYPE_LPM_TRIE

Signed-off-by: Anton Protopopov <[e-mail]>
---
 .../selftests/bpf/map_tests/map_pressure.c    | 309 ++++++++++++++++++
 1 file changed, 309 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/map_tests/map_pressure.c

Patch

diff --git a/tools/testing/selftests/bpf/map_tests/map_pressure.c b/tools/testing/selftests/bpf/map_tests/map_pressure.c
new file mode 100644
index 000000000000..c34ae31aef4b
--- /dev/null
+++ b/tools/testing/selftests/bpf/map_tests/map_pressure.c
@@ -0,0 +1,309 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Isovalent */
+
+#include <errno.h>
+#include <unistd.h>
+#include <pthread.h>
+
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include <bpf_util.h>
+#include <test_maps.h>
+
+#define MAX_ENTRIES 4096
+#define N_THREADS 17
+
+#define MAX_MAP_KEY_SIZE (sizeof(struct bpf_lpm_trie_key) + 4)
+
+static void map_info(int map_fd, struct bpf_map_info *info)
+{
+	__u32 len = sizeof(*info);
+	int ret;
+
+	memset(info, 0, sizeof(*info));
+
+	ret = bpf_obj_get_info_by_fd(map_fd, info, &len);
+	CHECK(ret < 0, "bpf_obj_get_info_by_fd", "error: %s\n", strerror(errno));
+}
+
+static const char *map_type_to_s(__u32 type)
+{
+	switch (type) {
+	case BPF_MAP_TYPE_HASH:
+		return "HASH";
+	case BPF_MAP_TYPE_PERCPU_HASH:
+		return "PERCPU_HASH";
+	case BPF_MAP_TYPE_LRU_HASH:
+		return "LRU_HASH";
+	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
+		return "LRU_PERCPU_HASH";
+	case BPF_MAP_TYPE_LPM_TRIE:
+		return "LPM_TRIE";
+	default:
+		return "<define-me>";
+	}
+}
+
+/* Map index -> map-type-specific-key */
+static void *map_key(__u32 type, __u32 i)
+{
+	static __thread __u8 key[MAX_MAP_KEY_SIZE];
+
+	if (type == BPF_MAP_TYPE_LPM_TRIE) {
+		/* prefixlen = 32, data[0..3] = i */
+		*(__u32 *)key = 32;
+		*(__u32 *)(key+4) = i;
+	} else {
+		*(__u32 *)key = i;
+	}
+	return key;
+}
+
+static __u32 map_count_elements(__u32 type, int map_fd)
+{
+	void *key = map_key(type, -1);
+	int n = 0;
+
+	while (!bpf_map_get_next_key(map_fd, key, key))
+		n++;
+	return n;
+}
+
+static void delete_all_elements(__u32 type, int map_fd)
+{
+	void *key = map_key(type, -1);
+	void *keys;
+	int n = 0;
+	int ret;
+
+	keys = calloc(MAX_MAP_KEY_SIZE, MAX_ENTRIES);
+	CHECK(!keys, "calloc", "error: %s\n", strerror(errno));
+
+	for (; !bpf_map_get_next_key(map_fd, key, key); n++)
+		memcpy(keys + n*MAX_MAP_KEY_SIZE, key, MAX_MAP_KEY_SIZE);
+
+	while (--n >= 0) {
+		ret = bpf_map_delete_elem(map_fd, keys + n*MAX_MAP_KEY_SIZE);
+		CHECK(ret < 0, "bpf_map_delete_elem", "error: %s\n", strerror(errno));
+	}
+}
+
+static bool is_lru(__u32 map_type)
+{
+	return map_type == BPF_MAP_TYPE_LRU_HASH ||
+	       map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
+}
+
+struct upsert_opts {
+	__u32 map_type;
+	int map_fd;
+	__u32 n;
+};
+
+static void *patch_map_thread(void *arg)
+{
+	struct upsert_opts *opts = arg;
+	void *key;
+	int val;
+	int ret;
+	int i;
+
+	for (i = 0; i < opts->n; i++) {
+		key = map_key(opts->map_type, i);
+		val = rand();
+		ret = bpf_map_update_elem(opts->map_fd, key, &val, 0);
+		CHECK(ret < 0, "bpf_map_update_elem", "error: %s\n", strerror(errno));
+	}
+	return NULL;
+}
+
+static void upsert_elements(struct upsert_opts *opts)
+{
+	pthread_t threads[N_THREADS];
+	int ret;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(threads); i++) {
+		ret = pthread_create(&i[threads], NULL, patch_map_thread, opts);
+		CHECK(ret != 0, "pthread_create", "error: %s\n", strerror(ret));
+	}
+
+	for (i = 0; i < ARRAY_SIZE(threads); i++) {
+		ret = pthread_join(i[threads], NULL);
+		CHECK(ret != 0, "pthread_join", "error: %s\n", strerror(ret));
+	}
+}
+
+static void __test_map_pressure(int map_fd)
+{
+	__u32 n = MAX_ENTRIES - 1000, current_elements;
+	struct upsert_opts opts = {
+		.map_fd = map_fd,
+		.n = n,
+	};
+	struct bpf_map_info info;
+
+	map_info(map_fd, &info);
+	opts.map_type = info.type;
+
+	/*
+	 * Upsert keys [0, n) under some competition: with random values from
+	 * N_THREADS threads
+	 */
+	upsert_elements(&opts);
+
+	/*
+	 * Raw pressure for all hashtable-based maps should be equal to the
+	 * number of elements present in the map. For non-lru maps this number
+	 * should be the number n of upserted elements. For lru maps some
+	 * elements might have been evicted. Check that all numbers make sense
+	 */
+	map_info(map_fd, &info);
+	current_elements = map_count_elements(info.type, map_fd);
+	if (!is_lru(info.type))
+		CHECK(n != current_elements, "map_count_elements",
+		      "current_elements(%u) != expected(%u)", current_elements, n);
+	CHECK(info.raw_pressure != current_elements, "map_pressure",
+	      "raw_pressure=%u, expected %u (map_type=%s,map_flags=%08x)\n",
+	      info.raw_pressure, current_elements, map_type_to_s(info.type), info.map_flags);
+
+	/*
+	 * Cleanup the map and check that all elements are actually gone and
+	 * that the map raw_pressure is back to 0 as well
+	 */
+	delete_all_elements(info.type, map_fd);
+	map_info(map_fd, &info);
+	current_elements = map_count_elements(info.type, map_fd);
+	CHECK(current_elements, "map_count_elements",
+	      "expected current_elements=0, got %u", current_elements);
+	CHECK(info.raw_pressure != 0, "map_pressure",
+	      "raw_pressure=%u, expected 0 (map_type=%s,map_flags=%08x)\n",
+	      info.raw_pressure, map_type_to_s(info.type), info.map_flags);
+
+	close(map_fd);
+}
+
+static int map_create_opts(__u32 type, const char *name,
+			   struct bpf_map_create_opts *map_opts,
+			   __u32 key_size, __u32 val_size)
+{
+	int map_fd;
+
+	map_fd = bpf_map_create(type, name, key_size, val_size, MAX_ENTRIES, map_opts);
+	CHECK(map_fd < 0, "bpf_map_create()", "error:%s (name=%s)\n",
+			strerror(errno), name);
+
+	return map_fd;
+}
+
+static int map_create(__u32 type, const char *name, struct bpf_map_create_opts *map_opts)
+{
+	return map_create_opts(type, name, map_opts, sizeof(int), sizeof(int));
+}
+
+static int create_hash(void)
+{
+	struct bpf_map_create_opts map_opts = {
+		.sz = sizeof(map_opts),
+		.map_flags = BPF_F_NO_PREALLOC,
+	};
+
+	return map_create(BPF_MAP_TYPE_HASH, "hash", &map_opts);
+}
+
+static int create_percpu_hash(void)
+{
+	struct bpf_map_create_opts map_opts = {
+		.sz = sizeof(map_opts),
+		.map_flags = BPF_F_NO_PREALLOC,
+	};
+
+	return map_create(BPF_MAP_TYPE_PERCPU_HASH, "percpu_hash", &map_opts);
+}
+
+static int create_hash_prealloc(void)
+{
+	return map_create(BPF_MAP_TYPE_HASH, "hash", NULL);
+}
+
+static int create_percpu_hash_prealloc(void)
+{
+	return map_create(BPF_MAP_TYPE_PERCPU_HASH, "percpu_hash_prealloc", NULL);
+}
+
+static int create_lru_hash(void)
+{
+	return map_create(BPF_MAP_TYPE_LRU_HASH, "lru_hash", NULL);
+}
+
+static int create_percpu_lru_hash(void)
+{
+	return map_create(BPF_MAP_TYPE_LRU_PERCPU_HASH, "lru_hash_percpu", NULL);
+}
+
+static int create_lpm_trie(void)
+{
+	struct bpf_map_create_opts map_opts = {
+		.sz = sizeof(map_opts),
+		.map_flags = BPF_F_NO_PREALLOC,
+	};
+	__u32 key_size = sizeof(struct bpf_lpm_trie_key) + 4;
+	__u32 val_size = sizeof(int);
+
+	return map_create_opts(BPF_MAP_TYPE_LPM_TRIE, "lpm_trie",
+			       &map_opts, key_size, val_size);
+}
+
+static void map_pressure_hash(void)
+{
+	__test_map_pressure(create_hash());
+	printf("test_%s:PASS\n", __func__);
+}
+
+static void map_pressure_percpu_hash(void)
+{
+	__test_map_pressure(create_percpu_hash());
+	printf("test_%s:PASS\n", __func__);
+}
+
+static void map_pressure_hash_prealloc(void)
+{
+	__test_map_pressure(create_hash_prealloc());
+	printf("test_%s:PASS\n", __func__);
+}
+
+static void map_pressure_percpu_hash_prealloc(void)
+{
+	__test_map_pressure(create_percpu_hash_prealloc());
+	printf("test_%s:PASS\n", __func__);
+}
+
+static void map_pressure_lru_hash(void)
+{
+	__test_map_pressure(create_lru_hash());
+	printf("test_%s:PASS\n", __func__);
+}
+
+static void map_pressure_percpu_lru_hash(void)
+{
+	__test_map_pressure(create_percpu_lru_hash());
+	printf("test_%s:PASS\n", __func__);
+}
+
+static void map_pressure_lpm_trie(void)
+{
+	__test_map_pressure(create_lpm_trie());
+	printf("test_%s:PASS\n", __func__);
+}
+
+void test_map_pressure(void)
+{
+	map_pressure_hash();
+	map_pressure_percpu_hash();
+	map_pressure_hash_prealloc();
+	map_pressure_percpu_hash_prealloc();
+	map_pressure_lru_hash();
+	map_pressure_percpu_lru_hash();
+	map_pressure_lpm_trie();
+}