linux-kernel - RE: [PATCH 2/2][v2] cpuidle-haltpoll: Build as module by default

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Message-ID: <17a6782c79a44aada31246ddefe02bfb@baidu.com>
Date:   Thu, 8 Dec 2022 02:32:15 +0000
From:   "Li,Rongqing" <lirongqing@...du.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
CC:     "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "daniel.lezcano@...aro.org" <daniel.lezcano@...aro.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "jpoimboe@...nel.org" <jpoimboe@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>
Subject: RE: [PATCH 2/2][v2] cpuidle-haltpoll: Build as module by default


> > Allow user to unload it in running
> 
> Just like that?  And corrupt things left and right while at it?
> 
> No way.
> 
> And why do you need this?

Cpuidle-haltpoll can not improve performance for all cases, like when guest has mwait, unixbench shows a small performance drop; 
So change it as module, user can insmod this drivers and rmmod this driver at run time

And some downstream os, centos and ubuntu build it module

Of cause, it will cause performance drop since it is not installed by default, but user insmod this module, this performance can restore, so I think this is acceptable
If this reasom is acceptable, I will add v3; or drop this patch.

Thanks

-Li