[PATCHSET v2 sched_ext/for-6.16] sched_ext: Introduce scx_sched

[Tejun Heo <tj@kernel.org>]

v[1] -> v2:

- 0003-sched_ext-Use-dynamic-allocation-for-scx_sched.patch updated to store
  scx_sched pointer in sched_ext_ops->priv so that bpf_scx_unreg() can
  determine the scx_sched to destroy regardless of where initialization
  failed. This will also help with supporting multiple schedulers.

- Minor updates to 0010-sched_ext-Move-event_stats_cpu-into-scx_sched.patch.

In preparation of supporting multiple hierarchical schedulers, this patchset
packages the states which are currently global but need to become per
scheduler instance into the new struct scx_sched.

Currently, the only supported scheduler instance is the system-wide root one
(scx_root) and the code assumes scx_root in many places. A follow-up
patchset will introduce multiple scheduler support scrutinizing and updating
each such occurrence appropriately.

There's significant amount of churning but most changes are straightforward
if not trivial, and no user visible changes are expected.

 0001-sched_ext-Introduce-scx_sched.patch
 0002-sched_ext-Avoid-NULL-scx_root-deref-through-SCX_HAS_.patch
 0003-sched_ext-Use-dynamic-allocation-for-scx_sched.patch
 0004-sched_ext-Inline-create_dsq-into-scx_bpf_create_dsq.patch
 0005-sched_ext-Factor-out-scx_alloc_and_add_sched.patch
 0006-sched_ext-Move-dsq_hash-into-scx_sched.patch
 0007-sched_ext-Move-global_dsqs-into-scx_sched.patch
 0008-sched_ext-Relocate-scx_event_stats-definition.patch
 0009-sched_ext-Factor-out-scx_read_events.patch
 0010-sched_ext-Move-event_stats_cpu-into-scx_sched.patch
 0011-sched_ext-Move-disable-machinery-into-scx_sched.patch
 0012-sched_ext-Clean-up-SCX_EXIT_NONE-handling-in-scx_dis.patch

and is also available in the following git branch:

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext.git scx_sched-v2

diffstat follows. Thanks.

 kernel/sched/ext.c      |  892 ++++++++++++++++++++++++++----------------------
 kernel/sched/ext_idle.c |    3
 2 files changed, 496 insertions(+), 399 deletions(-)

--
tejun

[1] http://lkml.kernel.org/r/20250423234542.1890867-1-tj@kernel.org