2024-03-06 05:34:21

by Gao Xiang

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

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 <[email protected]>
---
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

2024-03-06 06:52:15

by Gao Xiang

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

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 <[email protected]>
> ---
> 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,
> };

2024-03-06 07:55:21

by Jingbo Xu

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

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 <[email protected]>
>> ---
>>   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 \<[email protected]>

--
Thanks,
Jingbo

2024-03-07 01:09:32

by Chao Yu

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

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 <[email protected]>

Reviewed-by: Chao Yu <[email protected]>

Thanks,

2024-03-07 02:02:44

by Gao Xiang

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

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 <[email protected]>
>
> Reviewed-by: Chao Yu <[email protected]>

Thanks, added!

Thanks,
Gao Xiang

>
> Thanks,