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Split the function in preparation for calling > ttwu_do_migration() while already holding rq->lock. > [ ... ] This patch regresses schbench -L -m 4 -M auto -t 256 -n 0 -r 0 -s 0 from 5.2M RPS to 4.5M RPS, and profiles show that CPU 0-3 are spending more time in __task_rq_lock() > -static inline void psi_ttwu_dequeue(struct task_struct *p) > +static inline bool psi_ttwu_need_dequeue(struct task_struct *p) > { > if (static_branch_likely(&psi_disabled)) > - return; > + return false; > /* > * Is the task being migrated during a wakeup? Make sure to > * deregister its sleep-persistent psi states from the old > * queue, and let psi_enqueue() know it has to requeue. > */ > - if (unlikely(p->psi_flags)) { > - struct rq_flags rf; > - struct rq *rq; > - > - rq = __task_rq_lock(p, &rf); > - psi_task_change(p, p->psi_flags, 0); > - __task_rq_unlock(rq, &rf); > - } > + if (!likely(!p->psi_flags)) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ I think we need roughly one less bang? -chris