[Deepin-Kernel-SIG] [linux 6.6-y] [Upstream] Sync maple_tree patch series from mainline

[opsiff]

Merge patch series "maple_tree: iterator state changes"
These patches have some general cleanup and a change to separate the
maple state status tracking from the maple state node.

The maple state status change allows for walks to continue from previous
places when the status needs to be recorded to make logical sense for
the next call to the maple state. For instance, it allows for prev/next
to function in a way that better resembles the linked list. It also
allows switch statements to be used to detect missed states during
compile, and the addition of fast-path "active" state is cleaner as an
enum.

While making the status change, perf showed some very small (one line)
functions that were not inlined even with the inline key word. Making
these small functions __always_inline is less expensive according to
perf. As part of that change, some inlines have been dropped from
larger functions.

Perf also showed that the commonly used mas_for_each() iterator was
spending a lot of time finding the end of the node. This series
introduces caching of the end of the node in the maple state (and
updating it during writes). This caching along with the inline changes
yielded at 23.25% improvement on the BENCH_MAS_FOR_EACH maple tree test
framework benchmark.

I've also included a change to mtree_range_walk and mtree_lookup_walk to
take advantage of Peng's change [1] to the initial pivot setup.

mmtests did not produce any significant gains.

[1] https://lore.kernel.org/all/[email protected]/T/#u

Liam R. Howlett (12):
maple_tree: Remove unnecessary default labels from switch statements
maple_tree: Make mas_erase() more robust
maple_tree: Move debug check to __mas_set_range()
maple_tree: Add end of node tracking to the maple state
maple_tree: Use cached node end in mas_next()
maple_tree: Use cached node end in mas_destroy()
maple_tree: Clean up inlines for some functions
maple_tree: Separate ma_state node from status.
maple_tree: Remove mas_searchable()
maple_tree: Use maple state end for write operations
maple_tree: Don't find node end in mtree_lookup_walk()
maple_tree: mtree_range_walk() clean up

• Fixes:
  lib/maple_tree.c: fix build error due to hotfix alteration
  maple_tree: remove a BUG_ON() in mas_alloc_nodes()

Summary by Sourcery

Sync Maple Tree patch series from upstream: refactor iterator state status tracking, add cached node end, improve performance, and align code with mainline.

New Features:

• Separate maple state status from node pointers via a new enum and add end-of-node caching for faster walks

Bug Fixes:

• Fix build error in lib/maple_tree.c and remove a BUG_ON in mas_alloc_nodes

Enhancements:

• Convert small mapper helper functions to __always_inline and clean up default switch labels for performance
• Update mtree_range_walk and mtree_lookup_walk to leverage upstream initial pivot setup changes

Documentation:

• Document the new maple state status enum and its semantics in maple_tree.h

Tests:

• Adjust tests in lib/test_maple_tree.c to use the new status enum and add bench_load benchmark

[sourcery-ai]

Reviewer's Guide

This PR backports and integrates the upstream maple_tree iterator state overhaul: sentinel node pointers are replaced by an explicit status enum in ma_state, each node’s end offset is cached for faster prev/next walks, performance‐critical small helpers are forced __always_inline, switch statements are cleaned up, Peng’s new pivot setup is leveraged in range and lookup walks, and a build error plus an invalid BUG_ON are fixed.

Class diagram for updated maple_tree iterator state (ma_state)

classDiagram
    class ma_state {
        +maple_tree* tree
        +maple_enode* node
        +unsigned long index
        +unsigned long last
        +unsigned long min
        +unsigned long max
        +maple_alloc* alloc
        +maple_status status
        +unsigned char depth
        +unsigned char offset
        +unsigned char mas_flags
        +unsigned char end
    }
    class maple_status {
        ma_active
        ma_start
        ma_root
        ma_none
        ma_pause
        ma_overflow
        ma_underflow
        ma_error
    }
    ma_state --> maple_status : status
    class ma_wr_state {
        +ma_state* mas
        +unsigned long r_min
        +unsigned long r_max
        +maple_type type
        +unsigned char offset_end
        +unsigned long* pivots
        +unsigned long end_piv
        +void __rcu** slots
        +void* entry
        +void* content
    }
    ma_wr_state --> ma_state : mas

Loading

Class diagram for removal of sentinel node pointers in ma_state

classDiagram
    class ma_state {
        -maple_enode* node
        -MAS_START
        -MAS_ROOT
        -MAS_NONE
        -MAS_PAUSE
        -MAS_OVERFLOW
        -MAS_UNDERFLOW
        +enum maple_status status
        +maple_enode* node
    }
    class maple_status {
        ma_active
        ma_start
        ma_root
        ma_none
        ma_pause
        ma_overflow
        ma_underflow
        ma_error
    }
    ma_state --> maple_status : status

Loading

Class diagram for updated debug macros and counters (CONFIG_DEBUG_MAPLE_TREE)

classDiagram
    class maple_tree_tests_run {
        atomic_t maple_tree_tests_run
    }
    class maple_tree_tests_passed {
        atomic_t maple_tree_tests_passed
    }
    class mt_dump_format {
        mt_dump_dec
        mt_dump_hex
    }
    class mt_dump {
        +void mt_dump(const maple_tree*, mt_dump_format)
    }
    class mas_dump {
        +void mas_dump(const ma_state*)
    }
    class mas_wr_dump {
        +void mas_wr_dump(const ma_wr_state*)
    }
    class mt_validate {
        +void mt_validate(maple_tree*)
    }
    class mt_cache_shrink {
        +void mt_cache_shrink()
    }

Loading

File-Level Changes

Change	Details	Files
Introduce explicit enum maple_status and replace sentinel pointer values	Add enum maple_status and status field to struct ma_state Remove MAS_* pointer macros and update mas_is_* predicates and state transitions to use status Adjust mas_reset, mas_for_each and related APIs to initialize and test status Update test_maple_tree and tools/testing code to reference status instead of MAS_*	include/linux/maple_tree.h lib/maple_tree.c include/linux/mm_types.h mm/internal.h lib/test_maple_tree.c tools/testing/radix-tree/maple.c
Cache node end offset in ma_state for faster iteration	Add ‘end’ field to ma_state Set mas->end in mas_start, mas_next_node, mas_next_slot, mas_prev_slot, mas_wr_* paths Replace calls to ma_data_end in loops with cached mas->end	include/linux/maple_tree.h lib/maple_tree.c
Force inline key routines with __always_inline	Annotate small helpers (mte_node_type, ma_is_dense/leaf, mte_to_node, mt_locked, etc.) with __always_inline Drop redundant inlining attributes from callers	lib/maple_tree.c
Clean up switch statements and remove unnecessary defaults	Remove redundant default labels in mte_set_pivot and ma_slots switches Add explicit return NULL or unreachable paths as needed	lib/maple_tree.c
Leverage updated initial pivot setup in walks	Use mt_pivots[type] as end in mtree_lookup_walk instead of recalculated max Simplify mtree_range_walk logic by caching previous min/max and using early-offset detection	lib/maple_tree.c
Fix build error and remove invalid BUG_ON	Resolve build break in lib/maple_tree.c caused by hotfix alteration Remove an invalid BUG_ON in mas_alloc_nodes	lib/maple_tree.c

---

Tips and commands

Interacting with Sourcery

• Trigger a new review: Comment @sourcery-ai review on the pull request.
• Continue discussions: Reply directly to Sourcery's review comments.
• Generate a GitHub issue from a review comment: Ask Sourcery to create an
  issue from a review comment by replying to it. You can also reply to a
  review comment with @sourcery-ai issue to create an issue from it.
• Generate a pull request title: Write @sourcery-ai anywhere in the pull
  request title to generate a title at any time. You can also comment
  @sourcery-ai title on the pull request to (re-)generate the title at any time.
• Generate a pull request summary: Write @sourcery-ai summary anywhere in
  the pull request body to generate a PR summary at any time exactly where you
  want it. You can also comment @sourcery-ai summary on the pull request to
  (re-)generate the summary at any time.
• Generate reviewer's guide: Comment @sourcery-ai guide on the pull
  request to (re-)generate the reviewer's guide at any time.
• Resolve all Sourcery comments: Comment @sourcery-ai resolve on the
  pull request to resolve all Sourcery comments. Useful if you've already
  addressed all the comments and don't want to see them anymore.
• Dismiss all Sourcery reviews: Comment @sourcery-ai dismiss on the pull
  request to dismiss all existing Sourcery reviews. Especially useful if you
  want to start fresh with a new review - don't forget to comment
  @sourcery-ai review to trigger a new review!

Customizing Your Experience

Access your dashboard to:

• Enable or disable review features such as the Sourcery-generated pull request
  summary, the reviewer's guide, and others.
• Change the review language.
• Add, remove or edit custom review instructions.
• Adjust other review settings.

Getting Help

• Contact our support team for questions or feedback.
• Visit our documentation for detailed guides and information.
• Keep in touch with the Sourcery team by following us on X/Twitter, LinkedIn or GitHub.

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please ask for approval from opsiff. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• deepin/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[deepin-ci-robot]

deepin pr auto review

代码审查分析

总体概述

这个补丁主要是对 Maple Tree 实现进行了重构和优化，主要改进包括：

1. 引入了新的枚举类型 maple_status 来替代之前使用特殊指针值表示的状态
2. 改进了状态管理和错误处理机制
3. 增加了更多的边界检查和验证
4. 优化了一些关键路径的性能

具体分析

1. 状态管理改进

优点：

• 引入 enum maple_status 使状态管理更加清晰和类型安全
• 状态值不再依赖于特殊的指针值，提高了代码可读性
• 统一了状态检查函数，如 mas_is_active(), mas_is_none() 等

改进建议：

• 可以考虑为状态转换添加更多的验证，确保状态转换的合法性
• 在状态转换处添加更多的注释，说明转换的上下文和条件

2. 错误处理改进

优点：

• 使用 ma_error 状态统一处理错误情况
• 错误处理更加一致和可预测
• 移除了对特殊指针值的依赖

改进建议：

• 可以考虑为不同的错误类型定义更具体的错误码
• 在错误处理路径上添加更多的日志记录，便于调试

3. 性能优化

优点：

• 使用 __always_inline 优化关键路径函数
• 减少了不必要的函数调用
• 优化了状态检查逻辑

改进建议：

• 对于频繁调用的函数，可以考虑使用 static inline 而不是 __always_inline，让编译器决定是否内联
• 在性能关键路径上，可以考虑添加性能计数器，以便后续分析

4. 安全性改进

优点：

• 增加了更多的边界检查
• 改进了指针操作的安全性
• 增加了更多的断言和验证

改进建议：

• 可以考虑添加更多的运行时检查，特别是在调试版本中
• 对于用户输入的参数，可以添加更多的验证

5. 代码结构改进

优点：

• 代码组织更加清晰
• 函数职责更加明确
• 减少了代码重复

改进建议：

• 可以考虑将一些通用的辅助函数提取到单独的文件中
• 对于复杂的逻辑，可以考虑添加更多的注释说明

具体问题

1. 状态转换的一致性：

   • 在某些地方，状态转换的逻辑可能不够清晰
   • 建议在状态转换处添加更多的注释

2. 错误处理的完整性：

   • 某些错误情况可能没有被充分处理
   • 建议检查所有可能的错误路径

3. 性能影响：

   • 一些优化可能会增加代码大小
   • 建议在后续版本中监控性能影响

总结

这个补丁总体上是积极的改进，提高了代码的可读性、安全性和性能。主要的改进集中在状态管理、错误处理和性能优化方面。建议在合并前进行充分的测试，确保所有功能正常工作，并且性能测试通过。

对于后续的开发，建议：

1. 保持状态管理的一致性
2. 完善错误处理机制
3. 持续优化性能关键路径
4. 增加更多的测试用例，特别是边界情况

[sourcery-ai]

Sorry @opsiff, you have reached your weekly rate limit for Sourcery. Please try again later