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Subject: Re: [PATCH 0/3] add page_ext_data to get client data in page_ext
To:     Mike Rapoport <rppt@kernel.org>
Cc:     akpm@linux-foundation.org, pasha.tatashin@soleen.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20230718145812.1991717-1-shikemeng@huaweicloud.com>
 <20230719094421.GI1901145@kernel.org>
From:   Kemeng Shi <shikemeng@huaweicloud.com>
Message-ID: <aa2134aa-3767-b9fe-1504-d6945e8c2f7b@huaweicloud.com>
Date:   Thu, 20 Jul 2023 10:38:39 +0800
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on 7/19/2023 5:44 PM, Mike Rapoport wrote:
> On Tue, Jul 18, 2023 at 10:58:09PM +0800, Kemeng Shi wrote:
>> Current client get data from page_ext by adding offset which is auto
>> generated in page_ext core and expose the data layout design insdie
>> page_ext core. This series adds a page_ext_data to hide offset from
>> client. Thanks!
> 
> Implementers of page_ext_operations are anyway intimately related to
> page_ext, so I'm not convinced this has any value.
>  
Hi Mike, thanks for reply. I thinks page_ext_operations can be futher splited
into public part which used by client to simply register and private part which
only page_ext core cares and should not be accessed by client directly
to reduce decoupling. This series makes offset to be private which client
doesn't really care to hide data layout inside page_ext core from client.
There are some concrete gains I can list for now:
1. Future client cound call page_ext_data directly instead of define a
new function like get_page_owner to get it's data.
2. No change to client if layout of page_ext data change.
I hope this could be more convincing to you now.
Thanks!

-- 
Best wishes
Kemeng Shi