Re: [PATCH v7 1/1] rcu: Simplify rcu_init_nohz() cpumask handling

From: Paul E. McKenney
Date: Thu Sep 15 2022 - 16:25:10 EST


On Wed, Sep 14, 2022 at 04:30:06AM -0700, Paul E. McKenney wrote:
> On Wed, Sep 14, 2022 at 12:46:34PM +0200, Frederic Weisbecker wrote:
> > On Tue, Sep 13, 2022 at 11:00:36AM +0800, Zhen Lei wrote:
> > > In kernels built with either CONFIG_RCU_NOCB_CPU_DEFAULT_ALL=y or
> > > CONFIG_NO_HZ_FULL=y, additional CPUs must be added to rcu_nocb_mask.
> > > Except that kernels booted without the rcu_nocbs= will not have
> > > allocated rcu_nocb_mask. And the current rcu_init_nohz() function uses
> > > its need_rcu_nocb_mask and offload_all local variables to track the
> > > rcu_nocb and nohz_full state.
> > >
> > > But there is a much simpler approach, namely creating a cpumask pointer
> > > to track the default and then using cpumask_available() to check the
> > > rcu_nocb_mask state. This commit takes this approach, thereby simplifying
> > > and shortening the rcu_init_nohz() function.
> > >
> > > Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
> > > Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
> > > Acked-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
> >
> > Looks good, thanks!
>
> Queued and pushed, thank you all!

And this time, actually queued the most recent version. Apologies for
my confusion.

Thanx, Paul