From: Frederic Weisbecker <frederic@kernel.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Uladzislau Rezki <urezki@gmail.com>,
Boqun Feng <boqun.feng@gmail.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Neeraj Upadhyay <neeraju@codeaurora.org>,
Josh Triplett <josh@joshtriplett.org>,
Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH 1/2] srcu: Fix broken node geometry after early ssp init
Date: Mon, 19 Apr 2021 02:23:45 +0200 [thread overview]
Message-ID: <20210419002345.GA161053@lothringen> (raw)
In-Reply-To: <20210418044616.GE5006@paulmck-ThinkPad-P17-Gen-1>
On Sat, Apr 17, 2021 at 09:46:16PM -0700, Paul E. McKenney wrote:
> On Sat, Apr 17, 2021 at 03:16:49PM +0200, Frederic Weisbecker wrote:
> > On Wed, Apr 14, 2021 at 08:55:38AM -0700, Paul E. McKenney wrote:
> > > > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> > > > index 75ed367d5b60..24db97cbf76b 100644
> > > > --- a/kernel/rcu/rcu.h
> > > > +++ b/kernel/rcu/rcu.h
> > > > @@ -278,6 +278,7 @@ extern void resched_cpu(int cpu);
> > > > extern int rcu_num_lvls;
> > > > extern int num_rcu_lvl[];
> > > > extern int rcu_num_nodes;
> > > > +extern bool rcu_geometry_initialized;
> > >
> > > Can this be a static local variable inside rcu_init_geometry()?
> > >
> > > After all, init_srcu_struct() isn't called all that often, and its overhead
> > > is such that an extra function call and check is going to hurt it. This
> > > of course requires removing __init from rcu_init_geometry(), but it is not
> > > all that large, so why not just remove the __init?
> > >
> > > But if we really are worried about reclaiming rcu_init_geometry()'s
> > > instructions (maybe we are?), then rcu_init_geometry() can be split
> > > into a function that just does the check (which is not __init) and the
> > > remainder of the function, which could remain __init.
> >
> > There you go:
>
> Queued, thank you!
Thanks!
And please also consider "[PATCH 2/2] srcu: Early test SRCU polling start"
if you want to expand testing coverage to polling.
next prev parent reply other threads:[~2021-04-19 0:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 13:24 [PATCH 0/2] srcu: Fix early boot hang v3 Frederic Weisbecker
2021-04-14 13:24 ` [PATCH 1/2] srcu: Fix broken node geometry after early ssp init Frederic Weisbecker
2021-04-14 15:55 ` Paul E. McKenney
2021-04-16 23:38 ` Frederic Weisbecker
2021-04-17 13:16 ` Frederic Weisbecker
2021-04-18 4:46 ` Paul E. McKenney
2021-04-19 0:23 ` Frederic Weisbecker [this message]
2021-04-19 17:00 ` Paul E. McKenney
2021-04-14 13:24 ` [PATCH 2/2] srcu: Early test SRCU polling start Frederic Weisbecker
2021-04-14 15:56 ` Paul E. McKenney
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