linux-kernel - Re: [PATCH v2 0/2] arm64/mm: Enable color zero pages

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Message-ID: <2047fb91-da03-7774-ef5e-d194b92813c3@redhat.com>
Date:   Thu, 24 Sep 2020 08:47:09 +1000
From:   Gavin Shan <gshan@...hat.com>
To:     Catalin Marinas <catalin.marinas@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        mark.rutland@....com, anshuman.khandual@....com,
        robin.murphy@....com, will@...nel.org, shan.gavin@...il.com
Subject: Re: [PATCH v2 0/2] arm64/mm: Enable color zero pages

Hi Catalin,

On 9/23/20 6:43 PM, Catalin Marinas wrote:
> On Wed, Sep 23, 2020 at 03:37:19PM +1000, Gavin Shan wrote:
>> The feature of color zero pages isn't enabled on arm64, meaning all
>> read-only (anonymous) VM areas are backed up by same zero page. It
>> leads pressure to L1 (data) cache on reading data from them. This
>> tries to enable color zero pages.
>>
>> PATCH[1/2] decouples the zero PGD table from zero page
>> PATCH[2/2] allocates the needed zero pages according to L1 cache size
> 
> To save you (and potential reviewers) some time, please include in the
> cover letter details of a realistic workload/benchmark that is improved
> by this patchset, backed by numbers. Just because it's doable and the
> patches aren't too complex is not a good enough reason for merging.
> 

Sure, Please ignore this (v2) series for now. I'll try to provide
performance data in v3 even I'm not positive about that because
it depends on CPU's L1 dCache size :)

Cheers,
Gavin