Re: [PATCH 2/2] erofs: clean up preload_compressed_pages()

[Yue Hu]

On Wed,  2 Mar 2022 03:49:51 +0800
Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx> wrote:

> Rename preload_compressed_pages() as z_erofs_bind_cache()
> since we're try to prepare for adapting folios.
> 
> Also, add a comment for the gfp setting. No logic changes.
> 
> Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
> ---
>  fs/erofs/zdata.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index 2673fc105861..59aecf42e45c 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -219,13 +219,17 @@ struct z_erofs_decompress_frontend {
>  static struct page *z_pagemap_global[Z_EROFS_VMAP_GLOBAL_PAGES];
>  static DEFINE_MUTEX(z_pagemap_global_lock);
>  
> -static void preload_compressed_pages(struct z_erofs_decompress_frontend *fe,
> -				     struct address_space *mc,
> -				     enum z_erofs_cache_alloctype type,
> -				     struct page **pagepool)
> +static void z_erofs_bind_cache(struct z_erofs_decompress_frontend *fe,
> +			       enum z_erofs_cache_alloctype type,
> +			       struct page **pagepool)
>  {
> +	struct address_space *mc = MNGD_MAPPING(EROFS_I_SB(fe->inode));
>  	struct z_erofs_pcluster *pcl = fe->pcl;
>  	bool standalone = true;
> +	/*
> +	 * optimistic allocation without direct reclaim since inplace I/O
> +	 * can be used if low memory otherwise.
> +	 */
>  	gfp_t gfp = (mapping_gfp_mask(mc) & ~__GFP_DIRECT_RECLAIM) |
>  			__GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
>  	struct page **pages;
> @@ -703,17 +707,15 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
>  		WRITE_ONCE(fe->pcl->compressed_pages[0], fe->map.buf.page);
>  		fe->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
>  	} else {
> -		/* preload all compressed pages (can change mode if needed) */
> +		/* bind cache first when cached decompression is preferred */
>  		if (should_alloc_managed_pages(fe, sbi->opt.cache_strategy,
>  					       map->m_la))
>  			cache_strategy = TRYALLOC;
>  		else
>  			cache_strategy = DONTALLOC;
>  
> -		preload_compressed_pages(fe, MNGD_MAPPING(sbi),
> -					 cache_strategy, pagepool);
> +		z_erofs_bind_cache(fe, cache_strategy, pagepool);
>  	}
> -
>  hitted:
>  	/*
>  	 * Ensure the current partial page belongs to this submit chain rather

Reviewed-by: Yue Hu <huyue2@xxxxxxxxxxx>