Messages in this thread | | | From | Yun Levi <> | Date | Sat, 22 Jul 2023 10:23:26 +0100 | Subject | Re: [PATCH] rcu: remove unnecessary check cpu_no_qs.norm on rcu_report_qs_rdp |
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Hi, Paul.
Thanks for looking into this :)
> Except that rcu_report_qs_rdp() is invoked with interrupts enabled, > which means that there is some possibility of state changes up to the > raw_spin_lock_irqsave_rcu_node(rnp, flags) statement. > > So, did you check whether RCU's interrupt paths change this state?
In my narrow view, only a new gp started, cpu_no_qs.b.norm changes as true in the path of rcu_sched_clock_irq. But in that case, rcu_report_qs_rdp isn't called.
Did I understand your question well and are there any missed paths I didn't see?
> Why not start with something like this? > > if (!WARN_ON_ONCE(!rdp->cpu_no_qs.b.norm) || > rdp->gp_seq != rnp->gp_seq || rdp->gpwrap) { >
Yes. but with different message
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