linux-kernel - Re: [PATCH v3 5/6] sparc/init: Remove on-stack cpumask var

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Date: Tue, 23 Apr 2024 19:32:26 +0200
From: Sam Ravnborg <sam@...nborg.org>
To: Dawei Li <dawei.li@...ngroup.cn>
Cc: davem@...emloft.net, andreas@...sler.com, sparclinux@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 5/6] sparc/init: Remove on-stack cpumask var

Hi Dawei.

On Tue, Apr 23, 2024 at 04:30:42PM +0800, Dawei Li wrote:
> In general it's preferable to avoid placing cpumasks on the stack, as
> for large values of NR_CPUS these can consume significant amounts of
> stack space and make stack overflows more likely.
> 
> Since the cpumask var resides in __init function, which means it's free
> of any concurrenct access, it can be safely marked with static to get
> rid of allocation on stack.
> 
> Signed-off-by: Dawei Li <dawei.li@...ngroup.cn>

I am not convinced this patch is the right approach, and I am not sure
it is worth trying to fix it.
This patch adds complexity, where the other patches simplified code.
I recommend to drop this, we can re-visit if this turns out to be a real
problem.

	Sam