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Subject: Re: [PATCH 4/5] fs/proc/page: use a folio in stable_page_flags()
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To:     Matthew Wilcox <willy@infradead.org>, <gourry.memverge@gmail.com>
CC:     Andrew Morton <akpm@linux-foundation.org>,
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From:   Kefeng Wang <wangkefeng.wang@huawei.com>
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On 2023/11/3 20:28, Matthew Wilcox wrote:
> On Fri, Nov 03, 2023 at 03:29:05PM +0800, Kefeng Wang wrote:
>> Replace ten compound_head() calls with one page_folio().
> 
> This is going to conflict with Gregory Price's work:
> 
> https://lore.kernel.org/linux-mm/ZUCD1dsbrFjdZgVv@memverge.com/
> 
> Perhaps the two of you can collaborate on a patch series?

Will check this patch.

> 
>>   	u |= kpf_copy_bit(k, KPF_SLAB,		PG_slab);
>> -	if (PageTail(page) && PageSlab(page))
>> +	if (PageTail(page) && folio_test_slab(folio))
>>   		u |= 1 << KPF_SLAB;
> 
> This doesn't make sense ...
> 

Yes, after commit dcb351cd095a ("page-flags: define behavior SL*B-
related flags on compound pages"), the slab could not be a tail,
I will drop this line.