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From:   Thomas Gleixner <tglx@linutronix.de>
To:     "Rafael J. Wysocki" <rafael@kernel.org>, lirongqing@baidu.com
Cc:     mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
        x86@kernel.org, rafael@kernel.org, daniel.lezcano@linaro.org,
        peterz@infradead.org, akpm@linux-foundation.org,
        tony.luck@intel.com, jpoimboe@kernel.org,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH] cpuidle-haltpoll: Disable kvm guest polling when
 mwait_idle is used
In-Reply-To: <CAJZ5v0gG93BXZWOcRVpng_EN-h4+sOyUqTc1XRt4xZkqMnaZZw@mail.gmail.com>
References: <1670308998-12313-1-git-send-email-lirongqing@baidu.com>
 <CAJZ5v0gG93BXZWOcRVpng_EN-h4+sOyUqTc1XRt4xZkqMnaZZw@mail.gmail.com>
Date:   Tue, 06 Dec 2022 13:08:10 +0100
Message-ID: <87mt80g2fp.ffs@tglx>
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On Tue, Dec 06 2022 at 12:59, Rafael J. Wysocki wrote:
> On Tue, Dec 6, 2022 at 7:43 AM <lirongqing@baidu.com> wrote:
>>
>> +bool is_mwait_idle(void)
>> +{
>> +       return x86_idle == mwait_idle;
>> +}
>> +EXPORT_SYMBOL_GPL(is_mwait_idle);

No, this is just another adhoc check, which scratches ONE particular itch.

>> @@ -111,6 +112,9 @@ static int __init haltpoll_init(void)
>>         if (!kvm_para_available() || !haltpoll_want())
>>                 return -ENODEV;
>>
>> +       if (is_mwait_idle())
>> +               return -ENODEV;
>> +
>
> So perhaps you could make default_enter_idle() be a bit more careful
> about what it calls as the "default idle" routine?

Correct. arch_cpu_idle() is the one which should be called.

Thanks,

        tglx