Commit e58358af authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Andrii Nakryiko
Browse files

selftests/bpf: Add a test for arena range tree algorithm 



Add a test that verifies specific behavior of arena range tree
algorithm and adjust existing big_alloc1 test due to use
of global data in arena.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20241108025616.17625-3-alexei.starovoitov@gmail.com
parent b7953797

tools/testing/selftests/bpf/progs/verifier_arena_large.c

+108 −2
Original line number Diff line number Diff line
@@ -29,12 +29,12 @@ int big_alloc1(void *ctx) 
	if (!page1)

		return 1;

	*page1 = 1;

	page2 = bpf_arena_alloc_pages(&arena, base + ARENA_SIZE - PAGE_SIZE,

	page2 = bpf_arena_alloc_pages(&arena, base + ARENA_SIZE - PAGE_SIZE * 2,

				      1, NUMA_NO_NODE, 0);

	if (!page2)

		return 2;

	*page2 = 2;

	no_page = bpf_arena_alloc_pages(&arena, base + ARENA_SIZE,

	no_page = bpf_arena_alloc_pages(&arena, base + ARENA_SIZE - PAGE_SIZE,

					1, NUMA_NO_NODE, 0);

	if (no_page)

		return 3;
@@ -66,4 +66,110 @@ int big_alloc1(void *ctx) 
#endif

	return 0;

}



#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)

#define PAGE_CNT 100

__u8 __arena * __arena page[PAGE_CNT]; /* occupies the first page */

__u8 __arena *base;



/*

 * Check that arena's range_tree algorithm allocates pages sequentially

 * on the first pass and then fills in all gaps on the second pass.

 */

__noinline int alloc_pages(int page_cnt, int pages_atonce, bool first_pass,

		int max_idx, int step)

{

	__u8 __arena *pg;

	int i, pg_idx;



	for (i = 0; i < page_cnt; i++) {

		pg = bpf_arena_alloc_pages(&arena, NULL, pages_atonce,

					   NUMA_NO_NODE, 0);

		if (!pg)

			return step;

		pg_idx = (pg - base) / PAGE_SIZE;

		if (first_pass) {

			/* Pages must be allocated sequentially */

			if (pg_idx != i)

				return step + 100;

		} else {

			/* Allocator must fill into gaps */

			if (pg_idx >= max_idx || (pg_idx & 1))

				return step + 200;

		}

		*pg = pg_idx;

		page[pg_idx] = pg;

		cond_break;

	}

	return 0;

}



SEC("syscall")

__success __retval(0)

int big_alloc2(void *ctx)

{

	__u8 __arena *pg;

	int i, err;



	base = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);

	if (!base)

		return 1;

	bpf_arena_free_pages(&arena, (void __arena *)base, 1);



	err = alloc_pages(PAGE_CNT, 1, true, PAGE_CNT, 2);

	if (err)

		return err;



	/* Clear all even pages */

	for (i = 0; i < PAGE_CNT; i += 2) {

		pg = page[i];

		if (*pg != i)

			return 3;

		bpf_arena_free_pages(&arena, (void __arena *)pg, 1);

		page[i] = NULL;

		cond_break;

	}



	/* Allocate into freed gaps */

	err = alloc_pages(PAGE_CNT / 2, 1, false, PAGE_CNT, 4);

	if (err)

		return err;



	/* Free pairs of pages */

	for (i = 0; i < PAGE_CNT; i += 4) {

		pg = page[i];

		if (*pg != i)

			return 5;

		bpf_arena_free_pages(&arena, (void __arena *)pg, 2);

		page[i] = NULL;

		page[i + 1] = NULL;

		cond_break;

	}



	/* Allocate 2 pages at a time into freed gaps */

	err = alloc_pages(PAGE_CNT / 4, 2, false, PAGE_CNT, 6);

	if (err)

		return err;



	/* Check pages without freeing */

	for (i = 0; i < PAGE_CNT; i += 2) {

		pg = page[i];

		if (*pg != i)

			return 7;

		cond_break;

	}



	pg = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);



	if (!pg)

		return 8;

	/*

	 * The first PAGE_CNT pages are occupied. The new page

	 * must be above.

	 */

	if ((pg - base) / PAGE_SIZE < PAGE_CNT)

		return 9;

	return 0;

}

#endif

char _license[] SEC("license") = "GPL";