[Deepin-Kernel-SIG] [linux 6.6-y] [Deepin] sched/fair: Disable newidle balance for KABI

[opsiff]

deepin inclusion
category: kabi

some kabi whitelist symbol changed, such as set_cpus_allowed_ptr..etc. the symbol chain is:
int wake_up_process(struct task_struct *tsk);->struct task_struct ->struct sched_dl_entity dl,*dl_server;
->struct rq *rq;
->struct sched_domain __rcu *sd;
->
+unsigned int newidle_call;
+unsigned int newidle_success;
+unsigned int newidle_ratio;

Before find the way to solve it, disable it for CONFIG_DEEPIN_KABI_RESERVE.

Log:

change set_cpus_allowed_ptr
change wake_up_process
change set_user_nice

Fixes: 97d5537 ("sched/fair: Proportional newidle balance")

Summary by Sourcery

Disable proportional newidle balancing when Deepin KABI reservation is enabled to preserve kernel ABI stability.

Enhancements:

• Guard newidle balancing statistics and randomized NI_RANDOM feature behind CONFIG_DEEPIN_KABI_RESERVE to avoid KABI-visible struct sched_domain changes.
• Initialize sched_domain instances without newidle statistics fields when KABI reservation is active.

Summary by Sourcery

Guard proportional newidle balancing and its statistics behind Deepin KABI reservation to avoid changing the sched_domain ABI layout.

Enhancements:

• Wrap newidle balance statistics fields in sched_domain and related initialization in sd_init() with CONFIG_DEEPIN_KABI_RESERVE to keep the struct layout stable.
• Disable NI_RANDOM-based proportional newidle balancing and its feature flag when Deepin KABI reservation is enabled.
• Include Deepin KABI header in scheduler topology to support the new configuration guard.

[deepin-ci-robot]

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[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

This PR conditionally disables the proportional newidle balancing feature and its associated statistics when Deepin KABI reservation is enabled, to keep sched_domain’s layout stable for KABI while preserving existing behavior otherwise.

Class diagram for sched_domain layout under CONFIG_DEEPIN_KABI_RESERVE

classDiagram
    class SchedulerConfig {
        <<config>>
        +bool CONFIG_DEEPIN_KABI_RESERVE
    }

    class sched_domain_non_kabi {
        +unsigned int nr_balance_failed
        +unsigned int newidle_call
        +unsigned int newidle_success
        +unsigned int newidle_ratio
        +u64 max_newidle_lb_cost
        +unsigned long last_decay_max_lb_cost
    }

    class sched_domain_kabi_reserve {
        +unsigned int nr_balance_failed
        +u64 max_newidle_lb_cost
        +unsigned long last_decay_max_lb_cost
    }

    SchedulerConfig --> sched_domain_non_kabi : CONFIG_DEEPIN_KABI_RESERVE = false
    SchedulerConfig --> sched_domain_kabi_reserve : CONFIG_DEEPIN_KABI_RESERVE = true

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Flow diagram for newidle balancing behavior with CONFIG_DEEPIN_KABI_RESERVE

flowchart TD
    A["CPU becomes newly idle"] --> B{CONFIG_DEEPIN_KABI_RESERVE}

    B -- false --> C["update_newidle_stats increments newidle_call and newidle_success"]
    C --> D{sched_feat NI_RANDOM}
    D -- true --> E["Apply randomized weighting for newidle balancing"]
    D -- false --> F["Use default weight for newidle balancing"]
    E --> G["Call load_balance with CPU_NEWLY_IDLE"]
    F --> G["Call load_balance with CPU_NEWLY_IDLE"]

    B -- true --> H["Skip newidle_call/newidle_success/newidle_ratio updates"]
    H --> I["NI_RANDOM feature disabled at compile time"]
    I --> J["Call load_balance with CPU_NEWLY_IDLE using default behavior"]

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File-Level Changes

Change	Details	Files
Hide newidle balancing statistics fields from sched_domain when Deepin KABI reservation is enabled to avoid KABI-visible struct changes.	Include Deepin KABI header in scheduler topology declarations to access CONFIG_DEEPIN_KABI_RESERVE. Wrap newidle_call, newidle_success, and newidle_ratio fields in struct sched_domain with a CONFIG_DEEPIN_KABI_RESERVE guard so they are omitted when KABI reservation is active.	include/linux/sched/topology.h
Disable runtime updating of newidle statistics under KABI reservation while keeping behavior unchanged otherwise.	Guard the body of update_newidle_stats with CONFIG_DEEPIN_KABI_RESERVE so calls become no-ops when KABI reservation is active. Ensure the function remains present so callers don’t need ifdefs, but internal accounting is skipped under KABI reservation.	kernel/sched/fair.c
Disable NI_RANDOM-based proportional newidle balancing when KABI reservation is enabled.	Wrap the NI_RANDOM feature definition in a CONFIG_DEEPIN_KABI_RESERVE guard so the feature is not available when KABI reservation is active. Guard the NI_RANDOM randomization logic in sched_balance_newidle with CONFIG_DEEPIN_KABI_RESERVE so the weight remains constant under KABI reservation.	kernel/sched/features.h kernel/sched/fair.c
Avoid initializing newidle statistics in sched_domain initialization when KABI reservation is enabled.	Guard initialization of newidle_call, newidle_success, and newidle_ratio in sd_init with CONFIG_DEEPIN_KABI_RESERVE so those fields are only set when they exist. Preserve all other sched_domain initialization paths unchanged.	kernel/sched/topology.c

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[Copilot]

Pull request overview

This PR disables proportional newidle balancing to preserve kernel ABI stability for Deepin by guarding struct members and features with CONFIG_DEEPIN_KABI_RESERVE. The changes prevent ABI breakage in exported symbols like wake_up_process and set_cpus_allowed_ptr by conditionally removing three new fields (newidle_call, newidle_success, newidle_ratio) from struct sched_domain that were added by commit 97d5537.

Changes:

• Conditionally removes three newidle statistics fields from struct sched_domain
• Guards the NI_RANDOM scheduler feature flag to disable proportional balancing
• Protects all code paths that use the removed fields and feature

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
include/linux/sched/topology.h	Adds deepin_kabi.h include and guards newidle statistics fields in struct sched_domain with CONFIG_DEEPIN_KABI_RESERVE
kernel/sched/topology.c	Conditionally excludes initialization of newidle statistics fields in sd_init()
kernel/sched/features.h	Guards the NI_RANDOM feature flag definition
kernel/sched/fair.c	Guards update_newidle_stats() implementation and NI_RANDOM-based proportional balancing logic

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[Avenger-285714]

This way of fixing is kind of gross...