sched/fair: Add sched_smt_active check for fastpaths

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For fastpaths such as wakeup and load balance even minimal code additions
can add up. is_core_idle is accessed during load balance.

Other callsites of is_core_idle make sched_smt_active() check first.
Make the same check in should_we_balance.

Rest of access to cpu_smt_mask isn't in fastpath.

Note: Remove the stale comment above is_core_idle. Enqueue methods
of fair aren't close to it anymore.

Suggested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://patch.msgid.link/20260515172456.542799-4-sshegde@linux.ibm.com

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Shrikanth Hegde 2026-05-15 22:54:55 +05:30 • committed by Peter Zijlstra

parent 5bc6ab2d42

commit 3dbb362f90

1 changed files with 4 additions and 5 deletions

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kernel/sched/fair.c

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