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Message-ID: <4b0d600e-654b-488f-8ac7-2a83d71d91d0@bytedance.com>
Date: Wed, 27 Mar 2024 10:00:46 +0800
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Subject: Re: [PATCH 1/3] mm: pgtable: correct the wrong comment about
 ptdesc->__page_flags
To: Vishal Moola <vishal.moola@gmail.com>
Cc: akpm@linux-foundation.org, hughd@google.com, david@redhat.com,
 rppt@kernel.org, willy@infradead.org, muchun.song@linux.dev,
 linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <cover.1709541697.git.zhengqi.arch@bytedance.com>
 <cc42d5915fd98fd802f920de243f535efcfe01db.1709541697.git.zhengqi.arch@bytedance.com>
 <ZgMeKa3ee7oHrkq5@fedora>
From: Qi Zheng <zhengqi.arch@bytedance.com>
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On 2024/3/27 03:12, Vishal Moola wrote:
> On Mon, Mar 04, 2024 at 07:07:18PM +0800, Qi Zheng wrote:
>> The commit 32cc0b7c9d50 ("powerpc: add pte_free_defer() for pgtables
>> sharing page") introduced the use of PageActive flag to page table
>> fragments tracking, so the ptdesc->__page_flags is not unused, so
>> correct the wrong comment.
> 
> Thanks for catching this!
> 
> In regards to naming, we're trying to prefix unused variables with
> __underscores so I'd prefer to see the __ eliminated from the
> ptdesc->page_flags field here as well. This doesn't warrant a fix
> as it is already in 6.9-rc1, but is something to keep in
> mind for the future. 

Got it.

> Aside from that, LGTM.
> 
> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>

Thanks!

>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>> ---
>>   include/linux/mm_types.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
>> index a7223ba3ea1e..5ea77969daae 100644
>> --- a/include/linux/mm_types.h
>> +++ b/include/linux/mm_types.h
>> @@ -419,7 +419,7 @@ FOLIO_MATCH(compound_head, _head_2a);
>>   
>>   /**
>>    * struct ptdesc -    Memory descriptor for page tables.
>> - * @__page_flags:     Same as page flags. Unused for page tables.
>> + * @__page_flags:     Same as page flags. Powerpc only.
>>    * @pt_rcu_head:      For freeing page table pages.
>>    * @pt_list:          List of used page tables. Used for s390 and x86.
>>    * @_pt_pad_1:        Padding that aliases with page's compound head.
>> -- 
>> 2.30.2
>>