linux-kernel - Re: [PATCH v2 1/3] x86: Use HALT in default_idle when idle=nomwait cmdline arg is passed

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Message-ID: <965cacad-474e-aa72-d5a7-fda8f2dc20bc@amd.com>
Date:   Fri, 6 May 2022 16:53:36 +0530
From:   Wyes Karny <wyes.karny@....com>
To:     Dave Hansen <dave.hansen@...el.com>, linux-kernel@...r.kernel.org
Cc:     Lewis.Carroll@....com, Mario.Limonciello@....com,
        gautham.shenoy@....com, Ananth.Narayan@....com, bharata@....com,
        len.brown@...el.com, x86@...nel.org, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        hpa@...or.com, peterz@...radead.org, chang.seok.bae@...el.com,
        keescook@...omium.org, metze@...ba.org, zhengqi.arch@...edance.com,
        mark.rutland@....com, puwen@...on.cn, rafael.j.wysocki@...el.com,
        andrew.cooper3@...rix.com, jing2.liu@...el.com,
        jmattson@...gle.com, pawan.kumar.gupta@...ux.intel.com
Subject: Re: [PATCH v2 1/3] x86: Use HALT in default_idle when idle=nomwait
 cmdline arg is passed

On 5/5/2022 10:43 PM, Dave Hansen wrote:
> On 5/5/22 03:48, Wyes Karny wrote:
>> When kernel is booted with idle=nomwait avoid selecting MWAIT
>> as the  default idle state.
>>
>> If the user boots the kernel with idle=nomwait, it is a clear
>> indication that they do not prefer the use of mwait as the default
>> idle state.  However, the current code does not take this into
>> consideration while selecting the default idle state on x86.
>>
>> This patch fixes it by checking for the idle=nomwait boot option in
>> prefer_mwait_c1_over_halt().
> 
> There are a couple of places in the existing documentation that talk
> about idle=nomwait.  Could you please fix those up to make it clear that
> the option is no longer specific to intel_idle?  We don't need a rewrite
> or anything, just some small tweaks in the language.

Sure, will do. Thanks!