From: Peng Zhang zhangpeng.00@bytedance.com

mainline inclusion from mainline-v6.8-rc1 commit 4f2267b58a22d972be98edef8e6b3c7a67c9fb91 category: performance bugzilla: https://gitee.com/openeuler/kernel/issues/I9AYM3 CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

--------------------------------

Patch series "Introduce __mt_dup() to improve the performance of fork()", v7.

This series introduces __mt_dup() to improve the performance of fork(). During the duplication process of mmap, all VMAs are traversed and inserted one by one into the new maple tree, causing the maple tree to be rebalanced multiple times. Balancing the maple tree is a costly operation. To duplicate VMAs more efficiently, mtree_dup() and __mt_dup() are introduced for the maple tree. They can efficiently duplicate a maple tree.

Here are some algorithmic details about {mtree,__mt}_dup(). We perform a DFS pre-order traversal of all nodes in the source maple tree. During this process, we fully copy the nodes from the source tree to the new tree. This involves memory allocation, and when encountering a new node, if it is a non-leaf node, all its child nodes are allocated at once.

This idea was originally from Liam R. Howlett's Maple Tree Work email, and I added some of my own ideas to implement it. Some previous discussions can be found in [1]. For a more detailed analysis of the algorithm, please refer to the logs for patch [3/10] and patch [10/10].

There is a "spawn" in byte-unixbench[2], which can be used to test the performance of fork(). I modified it slightly to make it work with different number of VMAs.

Below are the test results. The first row shows the number of VMAs. The second and third rows show the number of fork() calls per ten seconds, corresponding to next-20231006 and the this patchset, respectively. The test results were obtained with CPU binding to avoid scheduler load balancing that could cause unstable results. There are still some fluctuations in the test results, but at least they are better than the original performance.

21 121 221 421 821 1621 3221 6421 12821 25621 51221 112100 76261 54227 34035 20195 11112 6017 3161 1606 802 393 114558 83067 65008 45824 28751 16072 8922 4747 2436 1233 599 2.19% 8.92% 19.88% 34.64% 42.37% 44.64% 48.28% 50.17% 51.68% 53.74% 52.42%

Thanks to Liam and Matthew for the review.

This patch (of 10):

Add two helpers: 1. mt_free_one(), used to free a maple node. 2. mt_attr(), used to obtain the attributes of maple tree.

Link: https://lkml.kernel.org/r/20231027033845.90608-1-zhangpeng.00@bytedance.com Link: https://lkml.kernel.org/r/20231027033845.90608-2-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang zhangpeng.00@bytedance.com Reviewed-by: Liam R. Howlett Liam.Howlett@oracle.com Cc: Christian Brauner brauner@kernel.org Cc: Jonathan Corbet corbet@lwn.net Cc: Mateusz Guzik mjguzik@gmail.com Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Matthew Wilcox willy@infradead.org Cc: Michael S. Tsirkin mst@redhat.com Cc: Mike Christie michael.christie@oracle.com Cc: Nicholas Piggin npiggin@gmail.com Cc: Peter Zijlstra peterz@infradead.org Cc: Suren Baghdasaryan surenb@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: ZhangPeng zhangpeng362@huawei.com --- lib/maple_tree.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 684689457d77..f023b2bdde39 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -165,6 +165,11 @@ static inline int mt_alloc_bulk(gfp_t gfp, size_t size, void **nodes) return kmem_cache_alloc_bulk(maple_node_cache, gfp, size, nodes); }

+static inline void mt_free_one(struct maple_node *node) +{ + kmem_cache_free(maple_node_cache, node); +} + static inline void mt_free_bulk(size_t size, void __rcu **nodes) { kmem_cache_free_bulk(maple_node_cache, size, (void **)nodes); @@ -205,6 +210,11 @@ static unsigned int mas_mt_height(struct ma_state *mas) return mt_height(mas->tree); }

+static inline unsigned int mt_attr(struct maple_tree *mt) +{ + return mt->ma_flags & ~MT_FLAGS_HEIGHT_MASK; +} + static inline enum maple_type mte_node_type(const struct maple_enode *entry) { return ((unsigned long)entry >> MAPLE_NODE_TYPE_SHIFT) & @@ -5584,7 +5594,7 @@ void mas_destroy(struct ma_state *mas) mt_free_bulk(count, (void __rcu **)&node->slot[1]); total -= count; } - kmem_cache_free(maple_node_cache, node); + mt_free_one(ma_mnode_ptr(node)); total--; }

From: Peng Zhang zhangpeng.00@bytedance.com

mainline inclusion from mainline-v6.8-rc1 commit fd32e4e9b7646510ee9010e0d5f8b8857d48a6f7 category: performance bugzilla: https://gitee.com/openeuler/kernel/issues/I9AYM3 CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

--------------------------------

Introduce interfaces __mt_dup() and mtree_dup(), which are used to duplicate a maple tree. They duplicate a maple tree in Depth-First Search (DFS) pre-order traversal. It uses memcopy() to copy nodes in the source tree and allocate new child nodes in non-leaf nodes. The new node is exactly the same as the source node except for all the addresses stored in it. It will be faster than traversing all elements in the source tree and inserting them one by one into the new tree. The time complexity of these two functions is O(n).

The difference between __mt_dup() and mtree_dup() is that mtree_dup() handles locks internally.

Analysis of the average time complexity of this algorithm:

For simplicity, let's assume that the maximum branching factor of all non-leaf nodes is 16 (in allocation mode, it is 10), and the tree is a full tree.

Under the given conditions, if there is a maple tree with n elements, the number of its leaves is n/16. From bottom to top, the number of nodes in each level is 1/16 of the number of nodes in the level below. So the total number of nodes in the entire tree is given by the sum of n/16 + n/16^2 + n/16^3 + ... + 1. This is a geometric series, and it has log(n) terms with base 16. According to the formula for the sum of a geometric series, the sum of this series can be calculated as (n-1)/15. Each node has only one parent node pointer, which can be considered as an edge. In total, there are (n-1)/15-1 edges.

This algorithm consists of two operations:

1. Traversing all nodes in DFS order. 2. For each node, making a copy and performing necessary modifications to create a new node.

For the first part, DFS traversal will visit each edge twice. Let T(ascend) represent the cost of taking one step downwards, and T(descend) represent the cost of taking one step upwards. And both of them are constants (although mas_ascend() may not be, as it contains a loop, but here we ignore it and treat it as a constant). So the time spent on the first part can be represented as ((n-1)/15-1) * (T(ascend) + T(descend)).

For the second part, each node will be copied, and the cost of copying a node is denoted as T(copy_node). For each non-leaf node, it is necessary to reallocate all child nodes, and the cost of this operation is denoted as T(dup_alloc). The behavior behind memory allocation is complex and not specific to the maple tree operation. Here, we assume that the time required for a single allocation is constant. Since the size of a node is fixed, both of these symbols are also constants. We can calculate that the time spent on the second part is ((n-1)/15) * T(copy_node) + ((n-1)/15 - n/16) * T(dup_alloc).

Adding both parts together, the total time spent by the algorithm can be represented as:

((n-1)/15) * (T(ascend) + T(descend) + T(copy_node) + T(dup_alloc)) - n/16 * T(dup_alloc) - (T(ascend) + T(descend))

Let C1 = T(ascend) + T(descend) + T(copy_node) + T(dup_alloc) Let C2 = T(dup_alloc) Let C3 = T(ascend) + T(descend)

Finally, the expression can be simplified as: ((16 * C1 - 15 * C2) / (15 * 16)) * n - (C1 / 15 + C3).

This is a linear function, so the average time complexity is O(n).

Link: https://lkml.kernel.org/r/20231027033845.90608-4-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang zhangpeng.00@bytedance.com Suggested-by: Liam R. Howlett Liam.Howlett@oracle.com Cc: Christian Brauner brauner@kernel.org Cc: Jonathan Corbet corbet@lwn.net Cc: Mateusz Guzik mjguzik@gmail.com Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Matthew Wilcox willy@infradead.org Cc: Michael S. Tsirkin mst@redhat.com Cc: Mike Christie michael.christie@oracle.com Cc: Nicholas Piggin npiggin@gmail.com Cc: Peter Zijlstra peterz@infradead.org Cc: Suren Baghdasaryan surenb@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: ZhangPeng zhangpeng362@huawei.com --- include/linux/maple_tree.h | 3 + lib/maple_tree.c | 274 +++++++++++++++++++++++++++++++++++++ 2 files changed, 277 insertions(+)

diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h index f91dbc7fe091..a452dd8a1e5c 100644 --- a/include/linux/maple_tree.h +++ b/include/linux/maple_tree.h @@ -329,6 +329,9 @@ int mtree_store(struct maple_tree *mt, unsigned long index, void *entry, gfp_t gfp); void *mtree_erase(struct maple_tree *mt, unsigned long index);

+int mtree_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp); +int __mt_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp); + void mtree_destroy(struct maple_tree *mt); void __mt_destroy(struct maple_tree *mt);

diff --git a/lib/maple_tree.c b/lib/maple_tree.c index f023b2bdde39..bf4951fa7cd8 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -4,6 +4,8 @@ * Copyright (c) 2018-2022 Oracle Corporation * Authors: Liam R. Howlett Liam.Howlett@oracle.com * Matthew Wilcox willy@infradead.org + * Copyright (c) 2023 ByteDance + * Author: Peng Zhang zhangpeng.00@bytedance.com */

/* @@ -6486,6 +6488,278 @@ void *mtree_erase(struct maple_tree *mt, unsigned long index) } EXPORT_SYMBOL(mtree_erase);

+/* + * mas_dup_free() - Free an incomplete duplication of a tree. + * @mas: The maple state of a incomplete tree. + * + * The parameter @mas->node passed in indicates that the allocation failed on + * this node. This function frees all nodes starting from @mas->node in the + * reverse order of mas_dup_build(). There is no need to hold the source tree + * lock at this time. + */ +static void mas_dup_free(struct ma_state *mas) +{ + struct maple_node *node; + enum maple_type type; + void __rcu **slots; + unsigned char count, i; + + /* Maybe the first node allocation failed. */ + if (mas_is_none(mas)) + return; + + while (!mte_is_root(mas->node)) { + mas_ascend(mas); + if (mas->offset) { + mas->offset--; + do { + mas_descend(mas); + mas->offset = mas_data_end(mas); + } while (!mte_is_leaf(mas->node)); + + mas_ascend(mas); + } + + node = mte_to_node(mas->node); + type = mte_node_type(mas->node); + slots = ma_slots(node, type); + count = mas_data_end(mas) + 1; + for (i = 0; i < count; i++) + ((unsigned long *)slots)[i] &= ~MAPLE_NODE_MASK; + mt_free_bulk(count, slots); + } + + node = mte_to_node(mas->node); + mt_free_one(node); +} + +/* + * mas_copy_node() - Copy a maple node and replace the parent. + * @mas: The maple state of source tree. + * @new_mas: The maple state of new tree. + * @parent: The parent of the new node. + * + * Copy @mas->node to @new_mas->node, set @parent to be the parent of + * @new_mas->node. If memory allocation fails, @mas is set to -ENOMEM. + */ +static inline void mas_copy_node(struct ma_state *mas, struct ma_state *new_mas, + struct maple_pnode *parent) +{ + struct maple_node *node = mte_to_node(mas->node); + struct maple_node *new_node = mte_to_node(new_mas->node); + unsigned long val; + + /* Copy the node completely. */ + memcpy(new_node, node, sizeof(struct maple_node)); + /* Update the parent node pointer. */ + val = (unsigned long)node->parent & MAPLE_NODE_MASK; + new_node->parent = ma_parent_ptr(val | (unsigned long)parent); +} + +/* + * mas_dup_alloc() - Allocate child nodes for a maple node. + * @mas: The maple state of source tree. + * @new_mas: The maple state of new tree. + * @gfp: The GFP_FLAGS to use for allocations. + * + * This function allocates child nodes for @new_mas->node during the duplication + * process. If memory allocation fails, @mas is set to -ENOMEM. + */ +static inline void mas_dup_alloc(struct ma_state *mas, struct ma_state *new_mas, + gfp_t gfp) +{ + struct maple_node *node = mte_to_node(mas->node); + struct maple_node *new_node = mte_to_node(new_mas->node); + enum maple_type type; + unsigned char request, count, i; + void __rcu **slots; + void __rcu **new_slots; + unsigned long val; + + /* Allocate memory for child nodes. */ + type = mte_node_type(mas->node); + new_slots = ma_slots(new_node, type); + request = mas_data_end(mas) + 1; + count = mt_alloc_bulk(gfp, request, (void **)new_slots); + if (unlikely(count < request)) { + memset(new_slots, 0, request * sizeof(void *)); + mas_set_err(mas, -ENOMEM); + return; + } + + /* Restore node type information in slots. */ + slots = ma_slots(node, type); + for (i = 0; i < count; i++) { + val = (unsigned long)mt_slot_locked(mas->tree, slots, i); + val &= MAPLE_NODE_MASK; + ((unsigned long *)new_slots)[i] |= val; + } +} + +/* + * mas_dup_build() - Build a new maple tree from a source tree + * @mas: The maple state of source tree, need to be in MAS_START state. + * @new_mas: The maple state of new tree, need to be in MAS_START state. + * @gfp: The GFP_FLAGS to use for allocations. + * + * This function builds a new tree in DFS preorder. If the memory allocation + * fails, the error code -ENOMEM will be set in @mas, and @new_mas points to the + * last node. mas_dup_free() will free the incomplete duplication of a tree. + * + * Note that the attributes of the two trees need to be exactly the same, and the + * new tree needs to be empty, otherwise -EINVAL will be set in @mas. + */ +static inline void mas_dup_build(struct ma_state *mas, struct ma_state *new_mas, + gfp_t gfp) +{ + struct maple_node *node; + struct maple_pnode *parent = NULL; + struct maple_enode *root; + enum maple_type type; + + if (unlikely(mt_attr(mas->tree) != mt_attr(new_mas->tree)) || + unlikely(!mtree_empty(new_mas->tree))) { + mas_set_err(mas, -EINVAL); + return; + } + + root = mas_start(mas); + if (mas_is_ptr(mas) || mas_is_none(mas)) + goto set_new_tree; + + node = mt_alloc_one(gfp); + if (!node) { + new_mas->node = MAS_NONE; + mas_set_err(mas, -ENOMEM); + return; + } + + type = mte_node_type(mas->node); + root = mt_mk_node(node, type); + new_mas->node = root; + new_mas->min = 0; + new_mas->max = ULONG_MAX; + root = mte_mk_root(root); + while (1) { + mas_copy_node(mas, new_mas, parent); + if (!mte_is_leaf(mas->node)) { + /* Only allocate child nodes for non-leaf nodes. */ + mas_dup_alloc(mas, new_mas, gfp); + if (unlikely(mas_is_err(mas))) + return; + } else { + /* + * This is the last leaf node and duplication is + * completed. + */ + if (mas->max == ULONG_MAX) + goto done; + + /* This is not the last leaf node and needs to go up. */ + do { + mas_ascend(mas); + mas_ascend(new_mas); + } while (mas->offset == mas_data_end(mas)); + + /* Move to the next subtree. */ + mas->offset++; + new_mas->offset++; + } + + mas_descend(mas); + parent = ma_parent_ptr(mte_to_node(new_mas->node)); + mas_descend(new_mas); + mas->offset = 0; + new_mas->offset = 0; + } +done: + /* Specially handle the parent of the root node. */ + mte_to_node(root)->parent = ma_parent_ptr(mas_tree_parent(new_mas)); +set_new_tree: + /* Make them the same height */ + new_mas->tree->ma_flags = mas->tree->ma_flags; + rcu_assign_pointer(new_mas->tree->ma_root, root); +} + +/** + * __mt_dup(): Duplicate an entire maple tree + * @mt: The source maple tree + * @new: The new maple tree + * @gfp: The GFP_FLAGS to use for allocations + * + * This function duplicates a maple tree in Depth-First Search (DFS) pre-order + * traversal. It uses memcpy() to copy nodes in the source tree and allocate + * new child nodes in non-leaf nodes. The new node is exactly the same as the + * source node except for all the addresses stored in it. It will be faster than + * traversing all elements in the source tree and inserting them one by one into + * the new tree. + * The user needs to ensure that the attributes of the source tree and the new + * tree are the same, and the new tree needs to be an empty tree, otherwise + * -EINVAL will be returned. + * Note that the user needs to manually lock the source tree and the new tree. + * + * Return: 0 on success, -ENOMEM if memory could not be allocated, -EINVAL If + * the attributes of the two trees are different or the new tree is not an empty + * tree. + */ +int __mt_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp) +{ + int ret = 0; + MA_STATE(mas, mt, 0, 0); + MA_STATE(new_mas, new, 0, 0); + + mas_dup_build(&mas, &new_mas, gfp); + if (unlikely(mas_is_err(&mas))) { + ret = xa_err(mas.node); + if (ret == -ENOMEM) + mas_dup_free(&new_mas); + } + + return ret; +} +EXPORT_SYMBOL(__mt_dup); + +/** + * mtree_dup(): Duplicate an entire maple tree + * @mt: The source maple tree + * @new: The new maple tree + * @gfp: The GFP_FLAGS to use for allocations + * + * This function duplicates a maple tree in Depth-First Search (DFS) pre-order + * traversal. It uses memcpy() to copy nodes in the source tree and allocate + * new child nodes in non-leaf nodes. The new node is exactly the same as the + * source node except for all the addresses stored in it. It will be faster than + * traversing all elements in the source tree and inserting them one by one into + * the new tree. + * The user needs to ensure that the attributes of the source tree and the new + * tree are the same, and the new tree needs to be an empty tree, otherwise + * -EINVAL will be returned. + * + * Return: 0 on success, -ENOMEM if memory could not be allocated, -EINVAL If + * the attributes of the two trees are different or the new tree is not an empty + * tree. + */ +int mtree_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp) +{ + int ret = 0; + MA_STATE(mas, mt, 0, 0); + MA_STATE(new_mas, new, 0, 0); + + mas_lock(&new_mas); + mas_lock_nested(&mas, SINGLE_DEPTH_NESTING); + mas_dup_build(&mas, &new_mas, gfp); + mas_unlock(&mas); + if (unlikely(mas_is_err(&mas))) { + ret = xa_err(mas.node); + if (ret == -ENOMEM) + mas_dup_free(&new_mas); + } + + mas_unlock(&new_mas); + return ret; +} +EXPORT_SYMBOL(mtree_dup); + /** * __mt_destroy() - Walk and free all nodes of a locked maple tree. * @mt: The maple tree

From: Peng Zhang zhangpeng.00@bytedance.com

mainline inclusion from mainline-v6.8-rc1 commit a2587a7e8d37885dc063255f5400a66299b42e48 category: performance bugzilla: https://gitee.com/openeuler/kernel/issues/I9AYM3 CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

--------------------------------

Add test for mtree_dup().

Test by duplicating different maple trees and then comparing the two trees. Includes tests for duplicating full trees and memory allocation failures on different nodes.

Link: https://lkml.kernel.org/r/20231027033845.90608-6-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang zhangpeng.00@bytedance.com Reviewed-by: Liam R. Howlett Liam.Howlett@oracle.com Cc: Christian Brauner brauner@kernel.org Cc: Jonathan Corbet corbet@lwn.net Cc: Mateusz Guzik mjguzik@gmail.com Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Matthew Wilcox willy@infradead.org Cc: Michael S. Tsirkin mst@redhat.com Cc: Mike Christie michael.christie@oracle.com Cc: Nicholas Piggin npiggin@gmail.com Cc: Peter Zijlstra peterz@infradead.org Cc: Suren Baghdasaryan surenb@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: ZhangPeng zhangpeng362@huawei.com --- tools/testing/radix-tree/maple.c | 361 +++++++++++++++++++++++++++++++ 1 file changed, 361 insertions(+)

diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index 76a8990bb14e..8c02a6073454 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -35857,6 +35857,363 @@ static noinline void __init check_locky(struct maple_tree *mt) mt_clear_in_rcu(mt); }

+/* + * Compares two nodes except for the addresses stored in the nodes. + * Returns zero if they are the same, otherwise returns non-zero. + */ +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 __init void mas_subtree_max_range(struct ma_state *mas) +{ + unsigned long limit = mas->max; + MA_STATE(newmas, mas->tree, 0, 0); + void *entry; + + mas_for_each(mas, entry, limit) { + if (mas->last - mas->index >= + newmas.last - newmas.index) { + newmas = *mas; + } + } + + *mas = newmas; +} + +/* + * build_full_tree() - Build a full tree. + * @mt: The tree to build. + * @flags: Use @flags to build the tree. + * @height: The height of the tree to build. + * + * Build a tree with full leaf nodes and internal nodes. Note that the height + * should not exceed 3, otherwise it will take a long time to build. + * Return: zero if the build is successful, non-zero if it fails. + */ +static __init int build_full_tree(struct maple_tree *mt, unsigned int flags, + int height) +{ + MA_STATE(mas, mt, 0, 0); + unsigned long step; + int ret = 0, cnt = 1; + enum maple_type type; + + mt_init_flags(mt, flags); + mtree_insert_range(mt, 0, ULONG_MAX, xa_mk_value(5), GFP_KERNEL); + + mtree_lock(mt); + + while (1) { + mas_set(&mas, 0); + if (mt_height(mt) < height) { + mas.max = ULONG_MAX; + goto store; + } + + while (1) { + mas_dfs_preorder(&mas); + if (mas_is_none(&mas)) + goto unlock; + + type = mte_node_type(mas.node); + if (mas_data_end(&mas) + 1 < mt_slots[type]) { + mas_set(&mas, mas.min); + goto store; + } + } +store: + mas_subtree_max_range(&mas); + step = mas.last - mas.index; + if (step < 1) { + ret = -1; + goto unlock; + } + + step /= 2; + mas.last = mas.index + step; + mas_store_gfp(&mas, xa_mk_value(5), + GFP_KERNEL); + ++cnt; + } +unlock: + mtree_unlock(mt); + + MT_BUG_ON(mt, mt_height(mt) != height); + /* pr_info("height:%u number of elements:%d\n", mt_height(mt), cnt); */ + return ret; +} + +static noinline void __init check_mtree_dup(struct maple_tree *mt) +{ + DEFINE_MTREE(new); + int i, j, ret, count = 0; + unsigned int rand_seed = 17, rand; + + /* store a value at [0, 0] */ + mt_init_flags(mt, 0); + mtree_store_range(mt, 0, 0, xa_mk_value(0), GFP_KERNEL); + ret = mtree_dup(mt, &new, GFP_KERNEL); + MT_BUG_ON(&new, ret); + mt_validate(&new); + if (compare_tree(mt, &new)) + MT_BUG_ON(&new, 1); + + mtree_destroy(mt); + mtree_destroy(&new); + + /* The two trees have different attributes. */ + mt_init_flags(mt, 0); + mt_init_flags(&new, MT_FLAGS_ALLOC_RANGE); + ret = mtree_dup(mt, &new, GFP_KERNEL); + MT_BUG_ON(&new, ret != -EINVAL); + mtree_destroy(mt); + mtree_destroy(&new); + + /* The new tree is not empty */ + mt_init_flags(mt, 0); + mt_init_flags(&new, 0); + mtree_store(&new, 5, xa_mk_value(5), GFP_KERNEL); + ret = mtree_dup(mt, &new, GFP_KERNEL); + MT_BUG_ON(&new, ret != -EINVAL); + mtree_destroy(mt); + mtree_destroy(&new); + + /* Test for duplicating full trees. */ + for (i = 1; i <= 3; i++) { + ret = build_full_tree(mt, 0, i); + MT_BUG_ON(mt, ret); + mt_init_flags(&new, 0); + + ret = mtree_dup(mt, &new, GFP_KERNEL); + MT_BUG_ON(&new, ret); + mt_validate(&new); + if (compare_tree(mt, &new)) + MT_BUG_ON(&new, 1); + + mtree_destroy(mt); + mtree_destroy(&new); + } + + for (i = 1; i <= 3; i++) { + ret = build_full_tree(mt, MT_FLAGS_ALLOC_RANGE, i); + MT_BUG_ON(mt, ret); + mt_init_flags(&new, MT_FLAGS_ALLOC_RANGE); + + ret = mtree_dup(mt, &new, GFP_KERNEL); + MT_BUG_ON(&new, ret); + mt_validate(&new); + if (compare_tree(mt, &new)) + MT_BUG_ON(&new, 1); + + mtree_destroy(mt); + mtree_destroy(&new); + } + + /* Test for normal duplicating. */ + for (i = 0; i < 1000; i += 3) { + if (i & 1) { + mt_init_flags(mt, 0); + mt_init_flags(&new, 0); + } else { + mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE); + mt_init_flags(&new, MT_FLAGS_ALLOC_RANGE); + } + + for (j = 0; j < i; j++) { + mtree_store_range(mt, j * 10, j * 10 + 5, + xa_mk_value(j), GFP_KERNEL); + } + + ret = mtree_dup(mt, &new, GFP_KERNEL); + MT_BUG_ON(&new, ret); + mt_validate(&new); + if (compare_tree(mt, &new)) + MT_BUG_ON(&new, 1); + + mtree_destroy(mt); + mtree_destroy(&new); + } + + /* Test memory allocation failed. */ + mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE); + for (i = 0; i < 30; i += 3) { + mtree_store_range(mt, j * 10, j * 10 + 5, + xa_mk_value(j), GFP_KERNEL); + } + + /* Failed at the first node. */ + mt_init_flags(&new, MT_FLAGS_ALLOC_RANGE); + mt_set_non_kernel(0); + ret = mtree_dup(mt, &new, GFP_NOWAIT); + mt_set_non_kernel(0); + MT_BUG_ON(&new, ret != -ENOMEM); + mtree_destroy(mt); + mtree_destroy(&new); + + /* Random maple tree fails at a random node. */ + for (i = 0; i < 1000; i += 3) { + if (i & 1) { + mt_init_flags(mt, 0); + mt_init_flags(&new, 0); + } else { + mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE); + mt_init_flags(&new, MT_FLAGS_ALLOC_RANGE); + } + + for (j = 0; j < i; j++) { + mtree_store_range(mt, j * 10, j * 10 + 5, + xa_mk_value(j), GFP_KERNEL); + } + /* + * The rand() library function is not used, so we can generate + * the same random numbers on any platform. + */ + rand_seed = rand_seed * 1103515245 + 12345; + rand = rand_seed / 65536 % 128; + mt_set_non_kernel(rand); + + ret = mtree_dup(mt, &new, GFP_NOWAIT); + mt_set_non_kernel(0); + if (ret != 0) { + MT_BUG_ON(&new, ret != -ENOMEM); + count++; + mtree_destroy(mt); + continue; + } + + mt_validate(&new); + if (compare_tree(mt, &new)) + MT_BUG_ON(&new, 1); + + mtree_destroy(mt); + mtree_destroy(&new); + } + + /* pr_info("mtree_dup() fail %d times\n", count); */ + BUG_ON(!count); +} + extern void test_kmem_cache_bulk(void);

void farmer_tests(void) @@ -35904,6 +36261,10 @@ void farmer_tests(void) check_null_expand(&tree); mtree_destroy(&tree);

+ mt_init_flags(&tree, 0); + check_mtree_dup(&tree); + mtree_destroy(&tree); + /* RCU testing */ mt_init_flags(&tree, 0); check_erase_testset(&tree);

From: Peng Zhang zhangpeng.00@bytedance.com

mainline inclusion from mainline-v6.8-rc1 commit f670fa1caadb4ea532a89012c5451e4c6789bfcc category: performance bugzilla: https://gitee.com/openeuler/kernel/issues/I9AYM3 CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

--------------------------------

Skip other tests when BENCH is enabled so that performance can be measured in user space.

Link: https://lkml.kernel.org/r/20231027033845.90608-8-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang zhangpeng.00@bytedance.com Reviewed-by: Liam R. Howlett Liam.Howlett@oracle.com Cc: Christian Brauner brauner@kernel.org Cc: Jonathan Corbet corbet@lwn.net Cc: Mateusz Guzik mjguzik@gmail.com Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Matthew Wilcox willy@infradead.org Cc: Michael S. Tsirkin mst@redhat.com Cc: Mike Christie michael.christie@oracle.com Cc: Nicholas Piggin npiggin@gmail.com Cc: Peter Zijlstra peterz@infradead.org Cc: Suren Baghdasaryan surenb@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: ZhangPeng zhangpeng362@huawei.com --- lib/test_maple_tree.c | 8 ++++---- tools/testing/radix-tree/maple.c | 2 ++ 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c index 464eeb90d5ad..de470950714f 100644 --- a/lib/test_maple_tree.c +++ b/lib/test_maple_tree.c @@ -3585,10 +3585,6 @@ static int __init maple_tree_seed(void)

pr_info("\nTEST STARTING\n\n");

- mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE); - check_root_expand(&tree); - mtree_destroy(&tree); - #if defined(BENCH_SLOT_STORE) #define BENCH mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE); @@ -3646,6 +3642,10 @@ static int __init maple_tree_seed(void) goto skip; #endif

+ mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE); + check_root_expand(&tree); + mtree_destroy(&tree); + mt_init_flags(&tree, MT_FLAGS_ALLOC_RANGE); check_iteration(&tree); mtree_destroy(&tree); diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c index 8c02a6073454..059e6bcd6702 100644 --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -36299,7 +36299,9 @@ void farmer_tests(void)

void maple_tree_tests(void) { +#if !defined(BENCH) farmer_tests(); +#endif maple_tree_seed(); maple_tree_harvest(); }

From: Peng Zhang zhangpeng.00@bytedance.com

mainline inclusion from mainline-v6.8-rc1 commit 8e50d32c7a89bde896945e4e572ef28ccd87bbf8 category: performance bugzilla: https://gitee.com/openeuler/kernel/issues/I9AYM3 CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

--------------------------------

When destroying maple tree, preserve its attributes and then turn it into an empty tree. This allows it to be reused without needing to be reinitialized.

Link: https://lkml.kernel.org/r/20231027033845.90608-10-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang zhangpeng.00@bytedance.com Reviewed-by: Liam R. Howlett Liam.Howlett@oracle.com Cc: Christian Brauner brauner@kernel.org Cc: Jonathan Corbet corbet@lwn.net Cc: Mateusz Guzik mjguzik@gmail.com Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Matthew Wilcox willy@infradead.org Cc: Michael S. Tsirkin mst@redhat.com Cc: Mike Christie michael.christie@oracle.com Cc: Nicholas Piggin npiggin@gmail.com Cc: Peter Zijlstra peterz@infradead.org Cc: Suren Baghdasaryan surenb@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: ZhangPeng zhangpeng362@huawei.com --- lib/maple_tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c index bf4951fa7cd8..50f8a44f16db 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -6774,7 +6774,7 @@ void __mt_destroy(struct maple_tree *mt) if (xa_is_node(root)) mte_destroy_walk(root, mt);

- mt->ma_flags = 0; + mt->ma_flags = mt_attr(mt); } EXPORT_SYMBOL_GPL(__mt_destroy);