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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Thu, 8 Dec 2022 14:01:53 +0100
Message-ID: <CAJZ5v0iEYwrNjD5wqq-VA4C4KLwYL6O9SXu2bEEh87-4WmsExQ@mail.gmail.com>
Subject: Re: [PATCH 1/2][v2] cpuidle-haltpoll: Replace default_idle with arch_cpu_idle
To:     "Li,Rongqing" <lirongqing@baidu.com>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "bp@alien8.de" <bp@alien8.de>,
        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
        "x86@kernel.org" <x86@kernel.org>,
        "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        "tony.luck@intel.com" <tony.luck@intel.com>,
        "jpoimboe@kernel.org" <jpoimboe@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>
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On Thu, Dec 8, 2022 at 1:43 PM Li,Rongqing <lirongqing@baidu.com> wrote:
>
> > >
> > > When cpuidle-haltpoll is built as module,
> >
> > But it isn't now.
>
> Centos is compiling it as module, it will fail;
> Other user wants to compile it as module, they will fail,
> Syzbot random configuration building will fail
>
> Unless prohibit to build it as module as below:
>
> config HALTPOLL_CPUIDLE
> -        tristate "Halt poll cpuidle driver"
> +        bool "Halt poll cpuidle driver"
>         depends on X86 && KVM_GUEST
>         default y
>         help

Ah, OK.  Sorry about the confusion.

Yes, the driver (not the governor, though), can be modular, so yes you
need the export, but please change it to EXPORT_SYMBOL_GPL().