Re: [PATCH] mm/khugepaged: use page_cache_sync_ra() directly

[Dev Jain]

On 16/07/26 2:02 pm, Aditya Prakash Srivastava wrote:
> The static inline page_cache_sync_readahead() wrapper in pagemap.h
> is legacy and only wraps page_cache_sync_ra() after initializing

How exactly is this a legacy interface?

> a local readahead_control structure using DEFINE_READAHEAD.
> 
> Modernize the khugepaged readahead call by using page_cache_sync_ra()
> directly. This avoids the legacy wrapper and aligns the khugepaged
> readahead implementation with other subsystems in the kernel.

I can see multiple callers of page_cache_sync_readahead.
> 
> No functional change is introduced, as the logic and behavior
> remain identical.
> 
> Signed-off-by: Aditya Prakash Srivastava <aditya.ansh182@xxxxxxxxx>
> ---
>  mm/khugepaged.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 617bca76db49..2682b39401b2 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -2331,10 +2331,10 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr,
>  			}
>  		} else {	/* !is_shmem */
>  			if (!folio || xa_is_value(folio)) {
> +				DEFINE_READAHEAD(ractl, file, &file->f_ra, mapping, index);
> +
>  				xas_unlock_irq(&xas);
> -				page_cache_sync_readahead(mapping, &file->f_ra,
> -							  file, index,
> -							  end - index);
> +				page_cache_sync_ra(&ractl, end - index);
>  				/* drain lru cache to help folio_isolate_lru() */
>  				lru_add_drain();
>  				folio = filemap_lock_folio(mapping, index);