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Message-ID: <248b946a-f42f-6b59-147c-c7dbbe03ef0d@bytedance.com>
Date:   Mon, 31 Jul 2023 20:32:40 +0800
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Subject: Re: [PATCH 05/11] maple_tree: Add test for mt_dup()
To:     "Liam R. Howlett" <Liam.Howlett@Oracle.com>
References: <20230726080916.17454-1-zhangpeng.00@bytedance.com>
 <20230726080916.17454-6-zhangpeng.00@bytedance.com>
 <20230726160607.eoobd4dyvryfb25a@revolver>
From:   Peng Zhang <zhangpeng.00@bytedance.com>
Cc:     Peng Zhang <zhangpeng.00@bytedance.com>, linux-doc@vger.kernel.org,
        linux-mm@kvack.org, avagin@gmail.com, npiggin@gmail.com,
        mathieu.desnoyers@efficios.com, peterz@infradead.org,
        michael.christie@oracle.com, surenb@google.com, brauner@kernel.org,
        willy@infradead.org, corbet@lwn.net, linux-fsdevel@vger.kernel.org,
        akpm@linux-foundation.org, linux-kernel@vger.kernel.org
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在 2023/7/27 00:06, Liam R. Howlett 写道:
> * 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.
I probably won't change the way I check metadata. But is there a way to
construct a full tree? All I can think of is to write new code to
construct a full tree.
> 
>> +
>> +		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.
Actually I have used other values before. I haven't thought of a good
value yet, probably a random number in a suitable range would be nice
too.

> 
>> +		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
>>
>>