Re: [PATCH 2/8] mm: merge writeout into pageout

[Baoquan He <baoquan.he@linux.dev>]

On 06/01/26 at 01:34pm, Christoph Hellwig wrote:
> writeout is only called from pageout, and a straight flow at the end, so
> merge the two functions.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  mm/vmscan.c | 63 ++++++++++++++++++++++++-----------------------------
>  1 file changed, 29 insertions(+), 34 deletions(-)

Reviewed-by: Baoquan He <baoquan.he@linux.dev>

> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index e8a90911bf88..d7303eea1265 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -612,45 +612,14 @@ typedef enum {
>  	PAGE_CLEAN,
>  } pageout_t;
>  
> -static pageout_t writeout(struct folio *folio, struct address_space *mapping,
> -		struct swap_iocb **plug, struct list_head *folio_list)
> -{
> -	int res;
> -
> -	folio_set_reclaim(folio);
> -
> -	/*
> -	 * The large shmem folio can be split if CONFIG_THP_SWAP is not enabled
> -	 * or we failed to allocate contiguous swap entries, in which case
> -	 * the split out folios get added back to folio_list.
> -	 */
> -	if (shmem_mapping(mapping))
> -		res = shmem_writeout(folio, plug, folio_list);
> -	else
> -		res = swap_writeout(folio, plug);
> -
> -	if (res < 0)
> -		handle_write_error(mapping, folio, res);
> -	if (res == AOP_WRITEPAGE_ACTIVATE) {
> -		folio_clear_reclaim(folio);
> -		return PAGE_ACTIVATE;
> -	}
> -
> -	/* synchronous write? */
> -	if (!folio_test_writeback(folio))
> -		folio_clear_reclaim(folio);
> -
> -	trace_mm_vmscan_write_folio(folio);
> -	node_stat_add_folio(folio, NR_VMSCAN_WRITE);
> -	return PAGE_SUCCESS;
> -}
> -
>  /*
>   * pageout is called by shrink_folio_list() for each dirty folio.
>   */
>  static pageout_t pageout(struct folio *folio, struct address_space *mapping,
>  			 struct swap_iocb **plug, struct list_head *folio_list)
>  {
> +	int res;
> +
>  	/*
>  	 * We no longer attempt to writeback filesystem folios here, other
>  	 * than tmpfs/shmem.  That's taken care of in page-writeback.
> @@ -674,7 +643,33 @@ static pageout_t pageout(struct folio *folio, struct address_space *mapping,
>  		return PAGE_ACTIVATE;
>  	if (!folio_clear_dirty_for_io(folio))
>  		return PAGE_CLEAN;
> -	return writeout(folio, mapping, plug, folio_list);
> +
> +	folio_set_reclaim(folio);
> +
> +	/*
> +	 * The large shmem folio can be split if CONFIG_THP_SWAP is not enabled
> +	 * or we failed to allocate contiguous swap entries, in which case
> +	 * the split out folios get added back to folio_list.
> +	 */
> +	if (shmem_mapping(mapping))
> +		res = shmem_writeout(folio, plug, folio_list);
> +	else
> +		res = swap_writeout(folio, plug);
> +
> +	if (res < 0)
> +		handle_write_error(mapping, folio, res);
> +	if (res == AOP_WRITEPAGE_ACTIVATE) {
> +		folio_clear_reclaim(folio);
> +		return PAGE_ACTIVATE;
> +	}
> +
> +	/* synchronous write? */
> +	if (!folio_test_writeback(folio))
> +		folio_clear_reclaim(folio);
> +
> +	trace_mm_vmscan_write_folio(folio);
> +	node_stat_add_folio(folio, NR_VMSCAN_WRITE);
> +	return PAGE_SUCCESS;
>  }
>  
>  /*
> -- 
> 2.53.0
>