[PATCH v2 0/3] sched/fair: Update decision matrix and rename pinned-task group state

[Jemmy Wong <jemmywong512@gmail.com>]

Patch 1 updates the group-type decision matrix above
sched_balance_find_src_group(), which was never extended for
group_smt_balance (fee1759e4f04) and group_llc_balance (f38cc2f0d8a3).

Patches 2-3 rename the state that records balancing failures caused by
cpus_ptr-pinned tasks. Since commit 6263322c5e8f ("sched/fair: Rewrite
group_imb trigger") it is an affinity flag, not a load-skew measure,
yet it kept the names group_imbalanced and sgc->imbalance, which
suggest a load skew and are easily confused with env->imbalance. They
become group_pinned_imb and sgc->pinned_imb.

Patch 1 does not depend on patches 2-3. No functional change.

Changes in v2:
 - Patch 1: llc_balance vs. local has_spare is "force", not "nr_idle"
   (Tim Chen); reword the changelog accordingly.
 - Patch 2: Rename to group_pinned_imb instead of group_pinned_task
   (Tim Chen).
 - Patch 3: Rename sgc->pinned_task to sgc->pinned_imb and the reader to
   sg_pinned_imb(), to match.

v1: https://lore.kernel.org/all/20260928042018.10618-1-jemmywong512@gmail.com/

Jemmy Wong (3):
  sched/fair: Add smt_balance and llc_balance to the decision matrix
  sched/fair: Rename group_imbalanced to group_pinned_imb
  sched/fair: Rename sgc->imbalance to sgc->pinned_imb

 kernel/sched/fair.c  | 66 +++++++++++++++++++++++---------------------
 kernel/sched/sched.h |  6 +++-
 2 files changed, 39 insertions(+), 33 deletions(-)

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2.54.0 (Apple Git-157)