git: 06ff5c4c600a - stable/12 - sched_ule(4): Fix interactive threads stealing.
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Date: Tue, 05 Oct 2021 02:29:00 UTC
The branch stable/12 has been updated by mav: URL: https://cgit.FreeBSD.org/src/commit/?id=06ff5c4c600a28c8c317aea3ca6c669bb8c50cf7 commit 06ff5c4c600a28c8c317aea3ca6c669bb8c50cf7 Author: Alexander Motin <mav@FreeBSD.org> AuthorDate: 2021-09-21 19:56:49 +0000 Commit: Alexander Motin <mav@FreeBSD.org> CommitDate: 2021-10-05 02:28:58 +0000 sched_ule(4): Fix interactive threads stealing. In scenarios when first thread in the queue can migrate to specified CPU, but later ones can't runq_steal_from() incorrectly returned NULL. MFC after: 2 weeks (cherry picked from commit bd84094a51c4648a7c97ececdaccfb30bc832096) --- sys/kern/sched_ule.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/sys/kern/sched_ule.c b/sys/kern/sched_ule.c index 50f037076f46..20835a0b2c5f 100644 --- a/sys/kern/sched_ule.c +++ b/sys/kern/sched_ule.c @@ -1127,10 +1127,12 @@ again: continue; rqh = &rq->rq_queues[bit + (i << RQB_L2BPW)]; TAILQ_FOREACH(td, rqh, td_runq) { - if (first && THREAD_CAN_MIGRATE(td) && - THREAD_CAN_SCHED(td, cpu)) - return (td); - first = td; + if (first) { + if (THREAD_CAN_MIGRATE(td) && + THREAD_CAN_SCHED(td, cpu)) + return (td); + } else + first = td; } } }