[PATCH] erofs: apply proper VMA alignment for memory mapped files on THP

[PATCH] erofs: apply proper VMA alignment for memory mapped files on THP

[Gao Xiang]

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").

Fixes: 06252e9ce05b ("erofs: dax support for non-tailpacking regular file")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
 fs/erofs/data.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index c98aeda8abb2..3d9721b3faa8 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -447,5 +447,6 @@ const struct file_operations erofs_file_fops = {
 	.llseek		= generic_file_llseek,
 	.read_iter	= erofs_file_read_iter,
 	.mmap		= erofs_file_mmap,
+	.get_unmapped_area = thp_get_unmapped_area,
 	.splice_read	= filemap_splice_read,
 };
-- 
2.39.3

Re: [PATCH] erofs: apply proper VMA alignment for memory mapped files on THP

[Gao Xiang]

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>
> ---
>   fs/erofs/data.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index c98aeda8abb2..3d9721b3faa8 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -447,5 +447,6 @@ const struct file_operations erofs_file_fops = {
>   	.llseek		= generic_file_llseek,
>   	.read_iter	= erofs_file_read_iter,
>   	.mmap		= erofs_file_mmap,
> +	.get_unmapped_area = thp_get_unmapped_area,
>   	.splice_read	= filemap_splice_read,
>   };

Re: [PATCH] erofs: apply proper VMA alignment for memory mapped files on THP

[Jingbo Xu]

On 3/6/24 2:51 PM, 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>
>> ---
>>   fs/erofs/data.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
>> index c98aeda8abb2..3d9721b3faa8 100644
>> --- a/fs/erofs/data.c
>> +++ b/fs/erofs/data.c
>> @@ -447,5 +447,6 @@ const struct file_operations erofs_file_fops = {
>>       .llseek        = generic_file_llseek,
>>       .read_iter    = erofs_file_read_iter,
>>       .mmap        = erofs_file_mmap,
>> +    .get_unmapped_area = thp_get_unmapped_area,
>>       .splice_read    = filemap_splice_read,
>>   };


LGTM.

Reviewed-by: Jingbo Xu \<jefflexu@linux.alibaba.com>

-- 
Thanks,
Jingbo

Re: [PATCH] erofs: apply proper VMA alignment for memory mapped files on THP

[Chao Yu]

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,

Re: [PATCH] erofs: apply proper VMA alignment for memory mapped files on THP

[Gao Xiang]

On 2024/3/7 09:07, Chao Yu wrote:
> 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, added!

Thanks,
Gao Xiang

> 
> Thanks,