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Linus Torvalds ed3b7923a8 Scheduler changes for v6.5:
- Scheduler SMP load-balancer improvements:
 
     - Avoid unnecessary migrations within SMT domains on hybrid systems.
 
       Problem:
 
         On hybrid CPU systems, (processors with a mixture of higher-frequency
 	SMT cores and lower-frequency non-SMT cores), under the old code
 	lower-priority CPUs pulled tasks from the higher-priority cores if
 	more than one SMT sibling was busy - resulting in many unnecessary
 	task migrations.
 
       Solution:
 
         The new code improves the load balancer to recognize SMT cores with more
         than one busy sibling and allows lower-priority CPUs to pull tasks, which
         avoids superfluous migrations and lets lower-priority cores inspect all SMT
         siblings for the busiest queue.
 
     - Implement the 'runnable boosting' feature in the EAS balancer: consider CPU
       contention in frequency, EAS max util & load-balance busiest CPU selection.
 
       This improves CPU utilization for certain workloads, while leaves other key
       workloads unchanged.
 
 - Scheduler infrastructure improvements:
 
     - Rewrite the scheduler topology setup code by consolidating it
       into the build_sched_topology() helper function and building
       it dynamically on the fly.
 
     - Resolve the local_clock() vs. noinstr complications by rewriting
       the code: provide separate sched_clock_noinstr() and
       local_clock_noinstr() functions to be used in instrumentation code,
       and make sure it is all instrumentation-safe.
 
 - Fixes:
 
     - Fix a kthread_park() race with wait_woken()
 
     - Fix misc wait_task_inactive() bugs unearthed by the -rt merge:
        - Fix UP PREEMPT bug by unifying the SMP and UP implementations.
        - Fix task_struct::saved_state handling.
 
     - Fix various rq clock update bugs, unearthed by turning on the rq clock
       debugging code.
 
     - Fix the PSI WINDOW_MIN_US trigger limit, which was easy to trigger by
       creating enough cgroups, by removing the warnign and restricting
       window size triggers to PSI file write-permission or CAP_SYS_RESOURCE.
 
     - Propagate SMT flags in the topology when removing degenerate domain
 
     - Fix grub_reclaim() calculation bug in the deadline scheduler code
 
     - Avoid resetting the min update period when it is unnecessary, in
       psi_trigger_destroy().
 
     - Don't balance a task to its current running CPU in load_balance(),
       which was possible on certain NUMA topologies with overlapping
       groups.
 
     - Fix the sched-debug printing of rq->nr_uninterruptible
 
 - Cleanups:
 
     - Address various -Wmissing-prototype warnings, as a preparation
       to (maybe) enable this warning in the future.
 
     - Remove unused code
 
     - Mark more functions __init
 
     - Fix shadow-variable warnings
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
 "Scheduler SMP load-balancer improvements:

   - Avoid unnecessary migrations within SMT domains on hybrid systems.

     Problem:

        On hybrid CPU systems, (processors with a mixture of
        higher-frequency SMT cores and lower-frequency non-SMT cores),
        under the old code lower-priority CPUs pulled tasks from the
        higher-priority cores if more than one SMT sibling was busy -
        resulting in many unnecessary task migrations.

     Solution:

        The new code improves the load balancer to recognize SMT cores
        with more than one busy sibling and allows lower-priority CPUs
        to pull tasks, which avoids superfluous migrations and lets
        lower-priority cores inspect all SMT siblings for the busiest
        queue.

   - Implement the 'runnable boosting' feature in the EAS balancer:
     consider CPU contention in frequency, EAS max util & load-balance
     busiest CPU selection.

     This improves CPU utilization for certain workloads, while leaves
     other key workloads unchanged.

  Scheduler infrastructure improvements:

   - Rewrite the scheduler topology setup code by consolidating it into
     the build_sched_topology() helper function and building it
     dynamically on the fly.

   - Resolve the local_clock() vs. noinstr complications by rewriting
     the code: provide separate sched_clock_noinstr() and
     local_clock_noinstr() functions to be used in instrumentation code,
     and make sure it is all instrumentation-safe.

  Fixes:

   - Fix a kthread_park() race with wait_woken()

   - Fix misc wait_task_inactive() bugs unearthed by the -rt merge:
       - Fix UP PREEMPT bug by unifying the SMP and UP implementations
       - Fix task_struct::saved_state handling

   - Fix various rq clock update bugs, unearthed by turning on the rq
     clock debugging code.

   - Fix the PSI WINDOW_MIN_US trigger limit, which was easy to trigger
     by creating enough cgroups, by removing the warnign and restricting
     window size triggers to PSI file write-permission or
     CAP_SYS_RESOURCE.

   - Propagate SMT flags in the topology when removing degenerate domain

   - Fix grub_reclaim() calculation bug in the deadline scheduler code

   - Avoid resetting the min update period when it is unnecessary, in
     psi_trigger_destroy().

   - Don't balance a task to its current running CPU in load_balance(),
     which was possible on certain NUMA topologies with overlapping
     groups.

   - Fix the sched-debug printing of rq->nr_uninterruptible

  Cleanups:

   - Address various -Wmissing-prototype warnings, as a preparation to
     (maybe) enable this warning in the future.

   - Remove unused code

   - Mark more functions __init

   - Fix shadow-variable warnings"

* tag 'sched-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
  sched/core: Avoid multiple calling update_rq_clock() in __cfsb_csd_unthrottle()
  sched/core: Avoid double calling update_rq_clock() in __balance_push_cpu_stop()
  sched/core: Fixed missing rq clock update before calling set_rq_offline()
  sched/deadline: Update GRUB description in the documentation
  sched/deadline: Fix bandwidth reclaim equation in GRUB
  sched/wait: Fix a kthread_park race with wait_woken()
  sched/topology: Mark set_sched_topology() __init
  sched/fair: Rename variable cpu_util eff_util
  arm64/arch_timer: Fix MMIO byteswap
  sched/fair, cpufreq: Introduce 'runnable boosting'
  sched/fair: Refactor CPU utilization functions
  cpuidle: Use local_clock_noinstr()
  sched/clock: Provide local_clock_noinstr()
  x86/tsc: Provide sched_clock_noinstr()
  clocksource: hyper-v: Provide noinstr sched_clock()
  clocksource: hyper-v: Adjust hv_read_tsc_page_tsc() to avoid special casing U64_MAX
  x86/vdso: Fix gettimeofday masking
  math64: Always inline u128 version of mul_u64_u64_shr()
  s390/time: Provide sched_clock_noinstr()
  loongarch: Provide noinstr sched_clock_read()
  ...
2023-06-27 14:03:21 -07:00
arch Scheduler changes for v6.5: 2023-06-27 14:03:21 -07:00
block for-6.5/block-2023-06-23 2023-06-26 12:47:20 -07:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto KEYS: asymmetric: Copy sig and digest in public_key_verify_signature() 2023-06-02 15:36:23 +02:00
Documentation Scheduler changes for v6.5: 2023-06-27 14:03:21 -07:00
drivers Scheduler changes for v6.5: 2023-06-27 14:03:21 -07:00
fs - Add support for unaccepted memory as specified in the UEFI spec v2.9. 2023-06-26 15:32:39 -07:00
include Scheduler changes for v6.5: 2023-06-27 14:03:21 -07:00
init Updates for the x86 boot process: 2023-06-26 13:39:10 -07:00
io_uring for-6.5/io_uring-2023-06-23 2023-06-26 12:30:26 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel Scheduler changes for v6.5: 2023-06-27 14:03:21 -07:00
lib - Remove the local symbols prefix of the get/put_user() exception 2023-06-27 12:25:42 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm - Address -Wmissing-prototype warnings 2023-06-26 16:43:54 -07:00
net for-6.5/io_uring-2023-06-23 2023-06-26 12:30:26 -07:00
rust rust: error: impl Debug for Error with errname() integration 2023-06-13 01:24:42 +02:00
samples samples/bpf: Drop unnecessary fallthrough 2023-05-16 19:44:05 +02:00
scripts Rust changes for v6.5 2023-06-26 09:35:50 -07:00
security fsverity updates for 6.5 2023-06-26 10:56:13 -07:00
sound ASoC: Fix for v6.4 2023-06-21 15:23:23 +02:00
tools - Remove the local symbols prefix of the get/put_user() exception 2023-06-27 12:25:42 -07:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Avoid illegal stage2 mapping on invalid memory slot 2023-06-22 15:14:57 -04:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap NFSD 6.5 Release Notes 2023-06-26 10:48:57 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS - Address -Wmissing-prototype warnings 2023-06-26 16:43:54 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Move the Arm architecture documentation under Documentation/arch/. This 2023-06-27 11:58:16 -07:00
Makefile Linux 6.4 2023-06-25 16:29:58 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.