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Date: Thu, 7 Mar 2024 09:07:01 +0800
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Subject: Re: [PATCH] erofs: apply proper VMA alignment for memory mapped files
 on THP
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To: Gao Xiang <hsiangkao@linux.alibaba.com>, linux-erofs@lists.ozlabs.org
Cc: LKML <linux-kernel@vger.kernel.org>
References: <20240306053138.2240206-1-hsiangkao@linux.alibaba.com>
 <30300dc7-3063-4e09-bb21-22951ec23a38@linux.alibaba.com>
From: Chao Yu <chao@kernel.org>
In-Reply-To: <30300dc7-3063-4e09-bb21-22951ec23a38@linux.alibaba.com>
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On 2024/3/6 14:51, Gao Xiang wrote:
> 
> 
> On 2024/3/6 13:31, Gao Xiang wrote:
>> There are mainly two reasons that thp_get_unmapped_area() should be
>> used for EROFS as other filesystems:
>>
>>   - It's needed to enable PMD mappings as a FSDAX filesystem, see
>>     commit 74d2fad1334d ("thp, dax: add thp_get_unmapped_area for pmd
>>     mappings");
>>
>>   - It's useful together with CONFIG_READ_ONLY_THP_FOR_FS which enables
>>     THPs for read-only mmapped files (e.g. shared libraries) even without
>>     FSDAX.  See commit 1854bc6e2420 ("mm/readahead: Align file mappings
>>     for non-DAX").
> 
> Refine this part as
> 
>   - It's useful together with large folios and CONFIG_READ_ONLY_THP_FOR_FS
>     which enable THPs for mmapped files (e.g. shared libraries) even without
>     ...
> 
>>
>> Fixes: 06252e9ce05b ("erofs: dax support for non-tailpacking regular file")
> 
> Fixes: ce529cc25b18 ("erofs: enable large folios for iomap mode")
> Fixes: be62c5198861 ("erofs: enable large folios for fscache mode")
> 
>> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,