linux/kernel/cgroup
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
..
cgroup-internal.h memcg: fix possible use-after-free in memcg_write_event_control() 2022-12-09 18:41:17 -08:00
cgroup-v1.c cgroup: fix missing cpus_read_{lock,unlock}() in cgroup_transfer_tasks() 2023-05-22 08:42:14 -10:00
cgroup.c Scheduler changes for v6.5: 2023-06-27 14:03:21 -07:00
cpuset.c cgroup changes for v6.4-rc1 2023-04-29 10:05:22 -07:00
debug.c kernel: cgroup: fix misuse of %x 2019-05-06 08:47:48 -07:00
freezer.c cgroup: cleanup comments 2022-03-13 19:19:27 -10:00
legacy_freezer.c cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex in freezer_css_{online,offline}() 2023-06-12 06:39:48 -10:00
Makefile cgroup: Add misc cgroup controller 2021-04-04 13:34:46 -04:00
misc.c misc_cgroup: remove error log to avoid log flood 2021-09-20 07:35:38 -10:00
namespace.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
pids.c cgroup: add pids.peak interface for pids controller 2022-09-04 09:26:51 -10:00
rdma.c cgroup: fix spelling mistakes 2021-05-24 12:45:26 -04:00
rstat.c - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of 2023-04-27 19:42:02 -07:00