linux-kernel - Re: [RFC PATCH 0/1] sched/isolation: Warn when maxcpus= is specified with nohz

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Message-ID: <5ba0869d-ac79-0776-7829-9c0856160918@atomlin.com>
Date: Wed, 8 Jan 2025 21:10:52 +0000 (GMT)
From: Aaron Tomlin <atomlin@...mlin.com>
To: Aaron Tomlin <atomlin@...mlin.com>
cc: oleg@...hat.com, frederic@...nel.org, peterz@...radead.org, 
    nick.lange@...il.com, seun.ewulomi@...il.com, mtosatti@...hat.com, 
    atomlin@...mlin.com, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 0/1] sched/isolation: Warn when maxcpus= is specified
 with nohz_full= or isolcpus=

On Sun, 1 Dec 2024, Aaron Tomlin wrote:
> Hi Oleg, Frederic, Peter,
>
> I have seen a case where maxcpus=1 and e.g. nohz_full=1,3-31, was used to
> force the CPU affinity of certain unbound or non CPU-specific kernel
> threads at boot-time. Albeit, since commit 9cc5b8656892a ("isolcpus: Affine
> unbound kernel threads to housekeeping cpus") this is handled entirely via
> nohz_full=. I thought it might be worth adding a warning.
>
>
> Aaron Tomlin (1):
>   sched/isolation: Warn when maxcpus= is specified with nohz_full= or
>     isolcpus=
>
>  kernel/sched/isolation.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> --
> 2.47.1

Hi Oleg, Frederic, Peter,

Any thoughts?


-- 
Aaron Tomlin