Re: [RFC 06/10] rcu/hotplug: Make rcutree_dead_cpu() parallel

From: Jason A. Donenfeld
Date: Wed Aug 24 2022 - 09:51:30 EST


On 8/22/22, Pingfan Liu <kernelfans@xxxxxxxxx> wrote:
> On Mon, Aug 22, 2022 at 02:08:38PM -0400, Joel Fernandes wrote:
>> On Sun, Aug 21, 2022 at 10:16 PM Pingfan Liu <kernelfans@xxxxxxxxx>
>> wrote:
>> >
>> > In order to support parallel, rcu_state.n_online_cpus should be
>> > atomic_dec()
>>
>> What does Parallel mean? Is that some kexec terminology?
>>
>
> 'Parallel' means concurrent. It is not a kexec terminology, instead,
> should be SMP.

Only sort of. See section A.6 of Paul 's book:
http://kernel.org/pub/linux/kernel/people/paulmck/perfbook/perfbook.html

Jason