linux-kernel - Re: [patch V3 06/11] x86/mm/cpa: Add large page preservation statistics

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Message-ID: <e72bda71-9aa6-3c1f-c224-09df181c38ec@intel.com>
Date:   Fri, 21 Sep 2018 12:59:39 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Peter Zijlstra <peterz@...radead.org>,
        Bin Yang <bin.yang@...el.com>,
        Mark Gross <mark.gross@...el.com>
Subject: Re: [patch V3 06/11] x86/mm/cpa: Add large page preservation
 statistics

On 09/17/2018 07:29 AM, Thomas Gleixner wrote:
> The large page preservation mechanism is just magic and provides no
> information at all. Add optional statistic output in debugfs so the magic can
> be evaluated. Defaults is off.
> 
> Output:
> 
>  1G pages checked:                    2
>  1G pages sameprot:                   0
>  1G pages preserved:                  0
>  2M pages checked:                  540
>  2M pages sameprot:                 466
>  2M pages preserved:                 47
>  4K pages checked:               800770
>  4K pages set-checked:             7668

Very nice, of course.

We've all rigged one of these up as we've played with this code, and
this will certainly help the next issue that we have.

Reviewed-by: Dave Hansen <dave.hansen@...el.com>