Merge tag 'sched_ext-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext

Pull sched_ext updates from Tejun Heo:

- Code organization cleanup. Separate internal types and accesso

Merge tag 'sched_ext-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext

Pull sched_ext updates from Tejun Heo:

- Code organization cleanup. Separate internal types and accessors to
ext_internal.h to reduce the size of ext.c and improve
maintainability.

- Prepare for cgroup sub-scheduler support by adding @sch parameter to
various functions and helpers, reorganizing scheduler instance
handling, and dropping obsolete helpers like scx_kf_exit() and
kf_cpu_valid().

- Add new scx_bpf_cpu_curr() and scx_bpf_locked_rq() BPF helpers to
provide safer access patterns with proper RCU protection.
scx_bpf_cpu_rq() is deprecated with warnings due to potential race
conditions.

- Improve debugging with migration-disabled counter in error state
dumps, SCX_EFLAG_INITIALIZED flag, bitfields for warning flags, and
other enhancements to help diagnose issues.

- Use cgroup_lock/unlock() for cgroup synchronization instead of
scx_cgroup_rwsem based synchronization. This is simpler and allows
enable/disable paths to synchronize against cgroup changes
independent of the CPU controller.

- rhashtable_lookup() replacement to avoid redundant RCU locking was
reverted due to RCU usage warnings. Will be redone once rhashtable is
updated to use rcu_dereference_all().

- Other misc updates and fixes including bypass handling improvements,
scx_task_iter_relock() improvements, tools/sched_ext updates, and
compatibility helpers.

* tag 'sched_ext-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (28 commits)
Revert "sched_ext: Use rhashtable_lookup() instead of rhashtable_lookup_fast()"
sched_ext: Misc updates around scx_sched instance pointer
sched_ext: Drop scx_kf_exit() and scx_kf_error()
sched_ext: Add the @sch parameter to scx_dsq_insert_preamble/commit()
sched_ext: Drop kf_cpu_valid()
sched_ext: Add the @sch parameter to ext_idle helpers
sched_ext: Add the @sch parameter to __bstr_format()
sched_ext: Separate out scx_kick_cpu() and add @sch to it
tools/sched_ext: scx_qmap: Make debug output quieter by default
sched_ext: Make qmap dump operation non-destructive
sched_ext: Add SCX_EFLAG_INITIALIZED to indicate successful ops.init()
sched_ext: Use bitfields for boolean warning flags
sched_ext: Fix stray scx_root usage in task_can_run_on_remote_rq()
sched_ext: Improve SCX_KF_DISPATCH comment
sched_ext: Use rhashtable_lookup() instead of rhashtable_lookup_fast()
sched_ext: Verify RCU protection in scx_bpf_cpu_curr()
sched_ext: Add migration-disabled counter to error state dump
sched_ext: Fix NULL dereference in scx_bpf_cpu_rq() warning
tools/sched_ext: Add compat helper for scx_bpf_cpu_curr()
sched_ext: deprecation warn for scx_bpf_cpu_rq()
...

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sched_ext: Add SCX_EFLAG_INITIALIZED to indicate successful ops.init()

ops.exit() may be called even if the loading failed before ops.init()
finishes successfully. This is because ops.exit() allows

sched_ext: Add SCX_EFLAG_INITIALIZED to indicate successful ops.init()

ops.exit() may be called even if the loading failed before ops.init()
finishes successfully. This is because ops.exit() allows rich exit info
communication. Add SCX_EFLAG_INITIALIZED flag to scx_exit_info.flags to
indicate whether ops.init() finished successfully.

This enables BPF schedulers to distinguish between exit scenarios and
handle cleanup appropriately based on initialization state.

Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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sched_ext: Use bitfields for boolean warning flags

Convert warned_zero_slice and warned_deprecated_rq in scx_sched struct to
single-bit bitfields. While this doesn't reduce struct size immediately,

sched_ext: Use bitfields for boolean warning flags

Convert warned_zero_slice and warned_deprecated_rq in scx_sched struct to
single-bit bitfields. While this doesn't reduce struct size immediately,
it prepares for future bitfield additions.

v2: Update patch description.

Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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sched_ext: deprecation warn for scx_bpf_cpu_rq()

scx_bpf_cpu_rq() works on an unlocked rq which generally isn't safe.
For the common use-cases scx_bpf_locked_rq() and
scx_bpf_cpu_curr() work, so add

sched_ext: deprecation warn for scx_bpf_cpu_rq()

scx_bpf_cpu_rq() works on an unlocked rq which generally isn't safe.
For the common use-cases scx_bpf_locked_rq() and
scx_bpf_cpu_curr() work, so add a deprecation warning
to scx_bpf_cpu_rq() so it can eventually be removed.

Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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sched_ext: Put event_stats_cpu in struct scx_sched_pcpu

scx_sched.event_stats_cpu is the percpu counters that are used to track
stats. Introduce struct scx_sched_pcpu and move the counters inside. T

sched_ext: Put event_stats_cpu in struct scx_sched_pcpu

scx_sched.event_stats_cpu is the percpu counters that are used to track
stats. Introduce struct scx_sched_pcpu and move the counters inside. This
will ease adding more per-cpu fields. No functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Andrea Righi <arighi@nvidia.com>

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sched_ext: Move internal type and accessor definitions to ext_internal.h

There currently isn't a place to place SCX-internal types and accessors to
be shared between ext.c and ext_idle.c. Create ker

sched_ext: Move internal type and accessor definitions to ext_internal.h

There currently isn't a place to place SCX-internal types and accessors to
be shared between ext.c and ext_idle.c. Create kernel/sched/ext_internal.h
and move internal type and accessor definitions there. This trims ext.c a
bit and makes future additions easier. Pure code reorganization. No
functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Andrea Righi <arighi@nvidia.com>

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