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Date:   Wed, 26 Jul 2023 12:06:07 -0400
From:   "Liam R. Howlett" <Liam.Howlett@Oracle.com>
To:     Peng Zhang <zhangpeng.00@bytedance.com>
Cc:     corbet@lwn.net, akpm@linux-foundation.org, willy@infradead.org,
        brauner@kernel.org, surenb@google.com, michael.christie@oracle.com,
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Subject: Re: [PATCH 05/11] maple_tree: Add test for mt_dup()
Message-ID: <20230726160607.eoobd4dyvryfb25a@revolver>
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References: <20230726080916.17454-1-zhangpeng.00@bytedance.com>
 <20230726080916.17454-6-zhangpeng.00@bytedance.com>
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* Peng Zhang <zhangpeng.00@bytedance.com> [230726 04:10]:
> Add test for mt_dup().
> 
> Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
> ---
>  tools/testing/radix-tree/maple.c | 202 +++++++++++++++++++++++++++++++
>  1 file changed, 202 insertions(+)
> 
> diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c
> index e5da1cad70ba..3052e899e5df 100644
> --- a/tools/testing/radix-tree/maple.c
> +++ b/tools/testing/radix-tree/maple.c
> @@ -35857,6 +35857,204 @@ static noinline void __init check_locky(struct maple_tree *mt)
>  	mt_clear_in_rcu(mt);
>  }
>  
> +/*
> + * Compare two nodes and return 0 if they are the same, non-zero otherwise.
> + */
> +static int __init compare_node(struct maple_enode *enode_a,
> +			       struct maple_enode *enode_b)
> +{
> +	struct maple_node *node_a, *node_b;
> +	struct maple_node a, b;
> +	void **slots_a, **slots_b; /* Do not use the rcu tag. */
> +	enum maple_type type;
> +	int i;
> +
> +	if (((unsigned long)enode_a & MAPLE_NODE_MASK) !=
> +	    ((unsigned long)enode_b & MAPLE_NODE_MASK)) {
> +		pr_err("The lower 8 bits of enode are different.\n");
> +		return -1;
> +	}
> +
> +	type = mte_node_type(enode_a);
> +	node_a = mte_to_node(enode_a);
> +	node_b = mte_to_node(enode_b);
> +	a = *node_a;
> +	b = *node_b;
> +
> +	/* Do not compare addresses. */
> +	if (ma_is_root(node_a) || ma_is_root(node_b)) {
> +		a.parent = (struct maple_pnode *)((unsigned long)a.parent &
> +						  MA_ROOT_PARENT);
> +		b.parent = (struct maple_pnode *)((unsigned long)b.parent &
> +						  MA_ROOT_PARENT);
> +	} else {
> +		a.parent = (struct maple_pnode *)((unsigned long)a.parent &
> +						  MAPLE_NODE_MASK);
> +		b.parent = (struct maple_pnode *)((unsigned long)b.parent &
> +						  MAPLE_NODE_MASK);
> +	}
> +
> +	if (a.parent != b.parent) {
> +		pr_err("The lower 8 bits of parents are different. %p %p\n",
> +			a.parent, b.parent);
> +		return -1;
> +	}
> +
> +	/*
> +	 * If it is a leaf node, the slots do not contain the node address, and
> +	 * no special processing of slots is required.
> +	 */
> +	if (ma_is_leaf(type))
> +		goto cmp;
> +
> +	slots_a = ma_slots(&a, type);
> +	slots_b = ma_slots(&b, type);
> +
> +	for (i = 0; i < mt_slots[type]; i++) {
> +		if (!slots_a[i] && !slots_b[i])
> +			break;
> +
> +		if (!slots_a[i] || !slots_b[i]) {
> +			pr_err("The number of slots is different.\n");
> +			return -1;
> +		}
> +
> +		/* Do not compare addresses in slots. */
> +		((unsigned long *)slots_a)[i] &= MAPLE_NODE_MASK;
> +		((unsigned long *)slots_b)[i] &= MAPLE_NODE_MASK;
> +	}
> +
> +cmp:
> +	/*
> +	 * Compare all contents of two nodes, including parent (except address),
> +	 * slots (except address), pivots, gaps and metadata.
> +	 */
> +	return memcmp(&a, &b, sizeof(struct maple_node));
> +}
> +
> +/*
> + * Compare two trees and return 0 if they are the same, non-zero otherwise.
> + */
> +static int __init compare_tree(struct maple_tree *mt_a, struct maple_tree *mt_b)
> +{
> +	MA_STATE(mas_a, mt_a, 0, 0);
> +	MA_STATE(mas_b, mt_b, 0, 0);
> +
> +	if (mt_a->ma_flags != mt_b->ma_flags) {
> +		pr_err("The flags of the two trees are different.\n");
> +		return -1;
> +	}
> +
> +	mas_dfs_preorder(&mas_a);
> +	mas_dfs_preorder(&mas_b);
> +
> +	if (mas_is_ptr(&mas_a) || mas_is_ptr(&mas_b)) {
> +		if (!(mas_is_ptr(&mas_a) && mas_is_ptr(&mas_b))) {
> +			pr_err("One is MAS_ROOT and the other is not.\n");
> +			return -1;
> +		}
> +		return 0;
> +	}
> +
> +	while (!mas_is_none(&mas_a) || !mas_is_none(&mas_b)) {
> +
> +		if (mas_is_none(&mas_a) || mas_is_none(&mas_b)) {
> +			pr_err("One is MAS_NONE and the other is not.\n");
> +			return -1;
> +		}
> +
> +		if (mas_a.min != mas_b.min ||
> +		    mas_a.max != mas_b.max) {
> +			pr_err("mas->min, mas->max do not match.\n");
> +			return -1;
> +		}
> +
> +		if (compare_node(mas_a.node, mas_b.node)) {
> +			pr_err("The contents of nodes %p and %p are different.\n",
> +			       mas_a.node, mas_b.node);
> +			mt_dump(mt_a, mt_dump_dec);
> +			mt_dump(mt_b, mt_dump_dec);
> +			return -1;
> +		}
> +
> +		mas_dfs_preorder(&mas_a);
> +		mas_dfs_preorder(&mas_b);
> +	}
> +
> +	return 0;
> +}
> +
> +static noinline void __init check_mt_dup(struct maple_tree *mt)
> +{
> +	DEFINE_MTREE(new);
> +	int i, j, ret, count = 0;
> +
> +	/* stored in the root pointer*/
> +	mt_init_flags(&tree, 0);
> +	mtree_store_range(&tree, 0, 0, xa_mk_value(0), GFP_KERNEL);
> +	mt_dup(&tree, &new, GFP_KERNEL);
> +	mt_validate(&new);
> +	if (compare_tree(&tree, &new))
> +		MT_BUG_ON(&new, 1);
> +
> +	mtree_destroy(&tree);
> +	mtree_destroy(&new);
> +
> +	for (i = 0; i < 1000; i += 3) {
> +		if (i & 1)
> +			mt_init_flags(&tree, 0);
> +		else
> +			mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE);
> +
> +		for (j = 0; j < i; j++) {
> +			mtree_store_range(&tree, j * 10, j * 10 + 5,
> +					  xa_mk_value(j), GFP_KERNEL);
> +		}

Storing in this way is probably not checking a full tree.  I think it's
important to check the full tree/full nodes since you have changes to
detect the metadata.

> +
> +		ret = mt_dup(&tree, &new, GFP_KERNEL);
> +		MT_BUG_ON(&new, ret != 0);
> +		mt_validate(&new);
> +		if (compare_tree(&tree, &new))
> +			MT_BUG_ON(&new, 1);
> +
> +		mtree_destroy(&tree);
> +		mtree_destroy(&new);
> +	}
> +
> +	/* Test memory allocation failed. */
> +	for (i = 0; i < 1000; i += 3) {
> +		if (i & 1)
> +			mt_init_flags(&tree, 0);
> +		else
> +			mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE);
> +
> +		for (j = 0; j < i; j++) {
> +			mtree_store_range(&tree, j * 10, j * 10 + 5,
> +					  xa_mk_value(j), GFP_KERNEL);
> +		}
> +
> +		mt_set_non_kernel(50);

It may be worth while allowing more/less than 50 allocations.

> +		ret = mt_dup(&tree, &new, GFP_NOWAIT);
> +		mt_set_non_kernel(0);
> +		if (ret != 0) {
> +			MT_BUG_ON(&new, ret != -ENOMEM);
> +			count++;
> +			mtree_destroy(&tree);
> +			continue;
> +		}
> +
> +		mt_validate(&new);
> +		if (compare_tree(&tree, &new))
> +			MT_BUG_ON(&new, 1);
> +
> +		mtree_destroy(&tree);
> +		mtree_destroy(&new);
> +	}
> +
> +	/* pr_info("mt_dup() fail %d times\n", count); */
> +	BUG_ON(!count);
> +}
> +
>  extern void test_kmem_cache_bulk(void);
>  
>  void farmer_tests(void)
> @@ -35904,6 +36102,10 @@ void farmer_tests(void)
>  	check_null_expand(&tree);
>  	mtree_destroy(&tree);
>  
> +	mt_init_flags(&tree, 0);
> +	check_mt_dup(&tree);
> +	mtree_destroy(&tree);
> +
>  	/* RCU testing */
>  	mt_init_flags(&tree, 0);
>  	check_erase_testset(&tree);
> -- 
> 2.20.1
> 
>