Re: [PATCH 10/11] btrfs: zstd use the passed through level instead of default

[Nikolay Borisov]

On 28.01.19 Ð. 23:24 Ñ., Dennis Zhou wrote:
> Zstd currently only supports the default level of compression. This
> patch switches to using the level passed in for btrfs zstd
> configuration.
> 
> Zstd workspaces now keep track of the requested level as this can differ
> from the size of the workspace.
> 
> Signed-off-by: Dennis Zhou <dennis@xxxxxxxxxx>

Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>

> ---
>  fs/btrfs/zstd.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
> index 43f3be755b8c..a951d4fe77f7 100644
> --- a/fs/btrfs/zstd.c
> +++ b/fs/btrfs/zstd.c
> @@ -21,10 +21,10 @@
>  #define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG)
>  #define ZSTD_BTRFS_DEFAULT_LEVEL 3
>  
> -static ZSTD_parameters zstd_get_btrfs_parameters(size_t src_len)
> +static ZSTD_parameters zstd_get_btrfs_parameters(unsigned int level,
> +						 size_t src_len)
>  {
> -	ZSTD_parameters params = ZSTD_getParams(ZSTD_BTRFS_DEFAULT_LEVEL,
> -						src_len, 0);
> +	ZSTD_parameters params = ZSTD_getParams(level, src_len, 0);
>  
>  	if (params.cParams.windowLog > ZSTD_BTRFS_MAX_WINDOWLOG)
>  		params.cParams.windowLog = ZSTD_BTRFS_MAX_WINDOWLOG;
> @@ -36,6 +36,7 @@ struct workspace {
>  	void *mem;
>  	size_t size;
>  	char *buf;
> +	unsigned int req_level;
>  	struct list_head list;
>  	ZSTD_inBuffer in_buf;
>  	ZSTD_outBuffer out_buf;
> @@ -55,7 +56,12 @@ static void zstd_cleanup_workspace_manager(void)
>  
>  static struct list_head *zstd_get_workspace(unsigned int level)
>  {
> -	return btrfs_get_workspace(&wsm, level);
> +	struct list_head *ws = btrfs_get_workspace(&wsm, level);
> +	struct workspace *workspace = list_entry(ws, struct workspace, list);
> +
> +	workspace->req_level = level;
> +
> +	return ws;
>  }
>  
>  static void zstd_put_workspace(struct list_head *ws)
> @@ -75,7 +81,7 @@ static void zstd_free_workspace(struct list_head *ws)
>  static struct list_head *zstd_alloc_workspace(unsigned int level)
>  {
>  	ZSTD_parameters params =
> -			zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT);
> +			zstd_get_btrfs_parameters(level, ZSTD_BTRFS_MAX_INPUT);
>  	struct workspace *workspace;
>  
>  	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
> @@ -117,7 +123,8 @@ static int zstd_compress_pages(struct list_head *ws,
>  	unsigned long len = *total_out;
>  	const unsigned long nr_dest_pages = *out_pages;
>  	unsigned long max_out = nr_dest_pages * PAGE_SIZE;
> -	ZSTD_parameters params = zstd_get_btrfs_parameters(len);
> +	ZSTD_parameters params = zstd_get_btrfs_parameters(workspace->req_level,
> +							   len);
>  
>  	*out_pages = 0;
>  	*total_out = 0;
>