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Linus Torvalds cb95904b47 Scheduler updates:
Kconfig updates:
 
  - Simplify PREEMPT_DYNAMIC (Mark Rutland)
 
 Fair scheduler updates:
 
  - Remove redundant RUN_TO_PARITY check (Elif Topuz)
 
  - Declare augmented callbacks per field, fix rb_add_augmented_cached()
    descent (Yiwei Lin, Peter Zijlstra)
 
  - Restart fair hrtick after same-task repicks (Shubhang Kaushik)
 
  - Improve the scheduling latency of short slice tasks (Vincent Guittot)
 
 Deadline/RT scheduler updates:
 
  - Check start_dl_timer expiry with ktime_before()
    (Liang Hao)
 
  - irq_work: CPU-hotplug improvements on PREEMPT_RT (Sebastian Andrzej
    Siewior)
 
 Energy-aware scheduling updates:
 
  - Implement the steal_governor, introduce preferred CPUs and
    steal-driven vCPU backoff (Shrikanth Hegde)
 
 Multi-processor load-balancing updates:
 
  - Enable preferred SMT siblings on NVIDIA Olympus (Andrea Righi)
 
  - Randomize equally shallow idle CPU picks (Christian Loehle)
 
  - Remove redundant core_sched_seq (Hui Su)
 
 Cache-aware scheduling updates:
 
  - Avoid publishing partial LLC utilization (Jemmy Wong)
 
 NUMA-balancing updates:
 
  - Reset NUMA fault locality after scan period update (Eric Kim)
 
 Proxy execution updates:
 
  - Ongoing work to implement sleeping owner handling for proxy
    execution (John Stultz, Vasily Gorbik)
 
  - Preparatory steps to make sched_ext compatible with proxy
    execution (Andrea Righi)
 
 Scheduler infrastructure updates & fixes:
 
  - Remove the RCU wait from PSI trigger destruction (Shakeel Butt)
 
  - Avoid modifying wait-entry on failed priority registration
    (Hui Su)
 
  - Use the new static key API for sched_feat (Hongyan Xia)
 
  - Convert paravirt_steal to new static key APIs (Hongyan Xia)
 
  - cputime: Don't account idle time twice after dyntick-idle
    (Stian Halseth)
 
 Scheduler debugging updates:
 
  - Set TIF_NEED_RESCHED before calling __trace_set_need_resched()
    (Sechang Lim)
 
  - Fix context analysis errors in non-preferred CPU push (Shrikanth
    Hegde)
 
 Misc cleanups and fixes by Christian Loehle, Shubhang Kaushik,
 Thomas Huth and Vladimir Zapolskiy.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2026-10-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
 "Kconfig updates:

   - Simplify PREEMPT_DYNAMIC (Mark Rutland)

  Fair scheduler updates:

   - Remove redundant RUN_TO_PARITY check (Elif Topuz)

   - Declare augmented callbacks per field, fix
     rb_add_augmented_cached() descent (Yiwei Lin, Peter Zijlstra)

   - Restart fair hrtick after same-task repicks (Shubhang Kaushik)

   - Improve the scheduling latency of short slice tasks (Vincent
     Guittot)

  Deadline/RT scheduler updates:

   - Check start_dl_timer expiry with ktime_before() (Liang Hao)

   - irq_work: CPU-hotplug improvements on PREEMPT_RT (Sebastian Andrzej
     Siewior)

  Energy-aware scheduling updates:

   - Implement the steal_governor, introduce preferred CPUs and
     steal-driven vCPU backoff (Shrikanth Hegde)

  Multi-processor load-balancing updates:

   - Enable preferred SMT siblings on NVIDIA Olympus (Andrea Righi)

   - Randomize equally shallow idle CPU picks (Christian Loehle)

   - Remove redundant core_sched_seq (Hui Su)

  Cache-aware scheduling updates:

   - Avoid publishing partial LLC utilization (Jemmy Wong)

  NUMA-balancing updates:

   - Reset NUMA fault locality after scan period update (Eric Kim)

  Proxy execution updates:

   - Ongoing work to implement sleeping owner handling for proxy
     execution (John Stultz, Vasily Gorbik)

   - Preparatory steps to make sched_ext compatible with proxy execution
     (Andrea Righi)

  Scheduler infrastructure updates & fixes:

   - Remove the RCU wait from PSI trigger destruction (Shakeel Butt)

   - Avoid modifying wait-entry on failed priority registration
     (Hui Su)

   - Use the new static key API for sched_feat (Hongyan Xia)

   - Convert paravirt_steal to new static key APIs (Hongyan Xia)

   - cputime: Don't account idle time twice after dyntick-idle
     (Stian Halseth)

  Scheduler debugging updates:

   - Set TIF_NEED_RESCHED before calling __trace_set_need_resched()
     (Sechang Lim)

   - Fix context analysis errors in non-preferred CPU push (Shrikanth
     Hegde)

  Misc cleanups and fixes by Christian Loehle, Shubhang Kaushik,
  Thomas Huth and Vladimir Zapolskiy"

* tag 'sched-core-2026-10-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  sched: Replace nr_iowait_cpu() with a bool accessor
  Revert "sched/fair: Remove dead code on enqueue_task_fair()"
  sched/cache: Avoid publishing partial LLC utilization
  sched/cputime: Don't account idle time twice after dyntick-idle
  sched/psi: Remove the RCU wait from trigger destruction
  sched/eevdf: Remove redundant RUN_TO_PARITY check
  sched/wait: Avoid modifying entry on failed priority registration
  rbtree_test: Use rb_add_augmented_cached() for the cached augmented test
  rbtree: Update augmented data on the way down in rb_add_augmented_cached()
  rbtree: Declare augmented callbacks per field with RB_AUG()
  rbtree_test: Use rb_add() and rb_add_cached() for the basic tests
  smpboot: Don't park the thread if work is pending
  irq_work: Flush lazy work CPU down on PREEMPT_RT
  irq_work: Update a comment regarding CPU hotplug invocation
  sched/topology: Add asymmetric SMT packing override
  sched/fair: Honor asymmetric SMT priority in idle selection
  sched: Set TIF_NEED_RESCHED before calling __trace_set_need_resched()
  sched/core: Fix context analysis errors in non-preferred CPU push
  virt/steal_governor: Enable the driver
  virt/steal_governor: Implement steal_governor policy loop
  ...
2026-10-20 12:35:35 -10:00
arch Scheduler updates: 2026-10-20 12:35:35 -10:00
block vfs-7.4-rc1.iomap 2026-10-19 18:33:02 -10:00
certs treewide: fix indentation and whitespace in Kconfig files 2026-05-28 21:24:42 -07:00
crypto crypto: aes - Fix undesired override of some optimized AES modes 2026-09-30 08:38:06 -07:00
Documentation Scheduler updates: 2026-10-20 12:35:35 -10:00
drivers Scheduler updates: 2026-10-20 12:35:35 -10:00
fs Scheduler updates: 2026-10-20 12:35:35 -10:00
include Scheduler updates: 2026-10-20 12:35:35 -10:00
init vfs-7.4-rc1.misc 2026-10-19 19:30:45 -10:00
io_uring vfs-7.4-rc1.file 2026-10-19 17:35:50 -10:00
ipc vfs-7.4-rc1.idmap 2026-10-19 17:57:49 -10:00
kernel Scheduler updates: 2026-10-20 12:35:35 -10:00
lib Scheduler updates: 2026-10-20 12:35:35 -10:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm vfs-7.4-rc1.idmap 2026-10-19 17:57:49 -10:00
net vfs-7.4-rc1.shared.net-next.pidfd 2026-10-19 20:32:52 -10:00
rust rust: net: netlink: validate attribute length before casting to c_int 2026-09-29 12:28:03 +02:00
samples samples: pidfd: fix userprogs typo 2026-10-14 22:08:01 +02:00
scripts Core features: 2026-10-20 07:55:19 -10:00
security vfs-7.4-rc1.idmap 2026-10-19 17:57:49 -10:00
sound ASoC: amd: yc: disable MSI on resume 2026-10-13 14:32:22 +01:00
tools Scheduler updates: 2026-10-20 12:35:35 -10:00
usr usr: Correct a spelling by changing a letter 2026-08-05 14:51:58 +02:00
virt vfs-7.4-rc1.idmap 2026-10-19 17:57:49 -10:00
.clang-format drm/bridge: rename drm_for_each_bridge_in_chain_scoped() to drm_for_each_bridge_in_chain() 2026-07-14 17:55:51 +02:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +02:00
.cocciconfig
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add myself 2026-09-07 10:01:33 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore SPDX patches for 7.2-rc1 2026-06-22 12:06:22 -07:00
.mailmap 7 hotfixes. 4 are cc:stable. 2026-10-08 12:35:20 +02:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS vfs-7.4-rc1.bfs 2026-10-19 16:55:31 -10:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Scheduler updates: 2026-10-20 12:35:35 -10:00
Makefile Linux 7.3 2026-10-18 13:14:58 -10:00
README README: remove out of place emdashes 2026-07-15 10:51:29 -06:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer: Getting started with kernel development
* Academic Researcher: Studying kernel internals and architecture
* Security Expert: Hardening and vulnerability analysis
* Backport/Maintenance Engineer: Maintaining stable kernels
* System Administrator: Configuring and troubleshooting
* Maintainer: Leading subsystems and reviewing patches
* Hardware Vendor: Writing drivers for new hardware
* Distribution Maintainer: Packaging kernels for distros
* AI Coding Assistant: LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst