Commit 5e9388f7 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by Alexei Starovoitov
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selftests/bpf: adapt one more case in test_lru_map to the new target_free 



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: d4adf1c9 ("bpf: Adjust free target to avoid global starvation of LRU map")
Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20250625210412.2732970-1-willemdebruijn.kernel@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent fa6f092c

tools/testing/selftests/bpf/test_lru_map.c

+18 −15
Original line number Diff line number Diff line
@@ -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++) {