From: Willem de Bruijn <willemb@xxxxxxxxxx>
The below commit that updated BPF_MAP_TYPE_LRU_HASH free target,
also updated tools/testing/selftests/bpf/test_lru_map to match.
But that missed one case that passes with 4 cores, but fails at
higher cpu counts.
Update test_lru_sanity3 to also adjust its expectation of target_free.
This time tested with 1, 4, 16, 64 and 384 cpu count.
Fixes: d4adf1c9ee77 ("bpf: Adjust free target to avoid global starvation of LRU map")
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
---
tools/testing/selftests/bpf/test_lru_map.c | 33 ++++++++++++----------
1 file changed, 18 insertions(+), 15 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_lru_map.c b/tools/testing/selftests/bpf/test_lru_map.c
index 4ae83f4b7fc7..0921939532c6 100644
--- a/tools/testing/selftests/bpf/test_lru_map.c
+++ b/tools/testing/selftests/bpf/test_lru_map.c
@@ -138,6 +138,12 @@ static int sched_next_online(int pid, int *next_to_try)
return ret;
}
+/* Derive target_free from map_size, same as bpf_common_lru_populate */
+static unsigned int __tgt_size(unsigned int map_size)
+{
+ return (map_size / nr_cpus) / 2;
+}
+
/* Inverse of how bpf_common_lru_populate derives target_free from map_size. */
static unsigned int __map_size(unsigned int tgt_free)
{
@@ -410,12 +416,12 @@ static void test_lru_sanity2(int map_type, int map_flags, unsigned int tgt_free)
printf("Pass\n");
}
-/* Size of the LRU map is 2*tgt_free
- * It is to test the active/inactive list rotation
- * Insert 1 to 2*tgt_free (+2*tgt_free keys)
- * Lookup key 1 to tgt_free*3/2
- * Add 1+2*tgt_free to tgt_free*5/2 (+tgt_free/2 keys)
- * => key 1+tgt_free*3/2 to 2*tgt_free are removed from LRU
+/* Test the active/inactive list rotation
+ *
+ * Fill the whole map, deplete the free list.
+ * Reference all except the last lru->target_free elements.
+ * Insert lru->target_free new elements. This triggers one shrink.
+ * Verify that the non-referenced elements are replaced.
*/
static void test_lru_sanity3(int map_type, int map_flags, unsigned int tgt_free)
{
@@ -434,8 +440,7 @@ static void test_lru_sanity3(int map_type, int map_flags, unsigned int tgt_free)
assert(sched_next_online(0, &next_cpu) != -1);
- batch_size = tgt_free / 2;
- assert(batch_size * 2 == tgt_free);
+ batch_size = __tgt_size(tgt_free);
map_size = tgt_free * 2;
lru_map_fd = create_map(map_type, map_flags, map_size);
@@ -446,23 +451,21 @@ static void test_lru_sanity3(int map_type, int map_flags, unsigned int tgt_free)
value[0] = 1234;
- /* Insert 1 to 2*tgt_free (+2*tgt_free keys) */
- end_key = 1 + (2 * tgt_free);
+ /* Fill the map */
+ end_key = 1 + map_size;
for (key = 1; key < end_key; key++)
assert(!bpf_map_update_elem(lru_map_fd, &key, value,
BPF_NOEXIST));
- /* Lookup key 1 to tgt_free*3/2 */
- end_key = tgt_free + batch_size;
+ /* Reference all but the last batch_size */
+ end_key = 1 + map_size - batch_size;
for (key = 1; key < end_key; key++) {
assert(!bpf_map_lookup_elem_with_ref_bit(lru_map_fd, key, value));
assert(!bpf_map_update_elem(expected_map_fd, &key, value,
BPF_NOEXIST));
}
- /* Add 1+2*tgt_free to tgt_free*5/2
- * (+tgt_free/2 keys)
- */
+ /* Insert new batch_size: replaces the non-referenced elements */
key = 2 * tgt_free + 1;
end_key = key + batch_size;
for (; key < end_key; key++) {
--
2.50.0.727.gbf7dc18ff4-goog
