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    SubjectRe: [PATCH 2/3] task: RCU protect tasks on the runqueue
    On Mon, Sep 02, 2019 at 11:52:01PM -0500, Eric W. Biederman wrote:

    > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
    > index 2b037f195473..802958407369 100644
    > --- a/kernel/sched/core.c
    > +++ b/kernel/sched/core.c

    > @@ -3857,7 +3857,7 @@ static void __sched notrace __schedule(bool preempt)
    >
    > if (likely(prev != next)) {
    > rq->nr_switches++;
    > - rq->curr = next;
    > + rcu_assign_pointer(rq->curr, next);
    > /*
    > * The membarrier system call requires each architecture
    > * to have a full memory barrier after updating

    This one is sad; it puts a (potentially) expensive barrier in here. And
    I'm not sure I can explain the need for it. That is, we've not changed
    @next before this and don't need to 'publish' it as such.

    Can we use RCU_INIT_POINTER() or simply WRITE_ONCE(), here?

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