sched/core: Get this cpu once in ttwu_queue_cond()

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Calling smp_processor_id() on:
 - In CONFIG_DEBUG_PREEMPT=y, if preemption/irq is disabled, then it does
   not print any warning.
 - In CONFIG_DEBUG_PREEMPT=n, it doesn't do anything apart from getting
   __smp_processor_id

So with both CONFIG_DEBUG_PREEMPT=y/n, in preemption disabled section
it is better to cache the value. It could save a few cycles. Though
tiny, repeated could add up to a small value.

ttwu_queue_cond is called with interrupt disabled. So preemption is
disabled. Hence cache the value once instead.

Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Link: https://patch.msgid.link/20260323193630.640311-3-sshegde@linux.ibm.com

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Shrikanth Hegde 2026-03-24 01:06:28 +05:30 • committed by Peter Zijlstra

parent 76504bce4e

commit 0e81fe79fe

1 changed files with 4 additions and 2 deletions

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kernel/sched/core.c

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