Received-SPF: pass (google.com: domain of linux-kernel+bounces-76325-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Date: Thu, 22 Feb 2024 13:26:44 +0300
From: Alexey Dobriyan <adobriyan@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpu: mark cpu_possible_mask as __ro_after_init
Message-ID: <f076212f-9b2a-4eb5-980b-3043e6dd57aa@p183>
References: <41cd78af-92a3-4f23-8c7a-4316a04a66d8@p183>
 <a1fafb71-cbd9-4d0b-8c3c-2b69be97db3e@roeck-us.net>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <a1fafb71-cbd9-4d0b-8c3c-2b69be97db3e@roeck-us.net>

On Wed, Feb 21, 2024 at 10:00:26PM -0800, Guenter Roeck wrote:
> On Mon, Feb 05, 2024 at 01:01:19PM +0300, Alexey Dobriyan wrote:
> > cpu_possible_mask is by definition "cpus which could be hotplugged
> > without reboot" -- property which is fixed after kernel enumerates
> > motheboard capabilities and hardware configuration.
> > 
> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> > ---
> > 
> >  kernel/cpu.c |    4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > --- a/kernel/cpu.c
> > +++ b/kernel/cpu.c
> > @@ -3107,10 +3107,10 @@ const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
> >  EXPORT_SYMBOL(cpu_all_bits);
> >  
> >  #ifdef CONFIG_INIT_ALL_POSSIBLE
> > -struct cpumask __cpu_possible_mask __read_mostly
> > +struct cpumask __cpu_possible_mask __ro_after_init;
> >  	= {CPU_BITS_ALL};
> 
> I guess you didn't compile test this code.

On parisc, no. Oh well.

> >  #else
> > -struct cpumask __cpu_possible_mask __read_mostly;
> > +struct cpumask __cpu_possible_mask __ro_after_init;