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

From: Chao Yu
Date: Wed Mar 06 2024 - 20:09:03 EST


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@xxxxxxxxxxxxxxxxx>

Reviewed-by: Chao Yu <chao@xxxxxxxxxx>

Thanks,