[PATCH v4 2/2] erofs: decompress in endio if possible

[Gao Xiang]

On Fri, Mar 05, 2021 at 04:21:42PM +0800, Huang Jianan via Linux-erofs wrote:
> z_erofs_decompressqueue_endio may not be executed in the atomic
> context, for example, when dm-verity is turned on. In this scenario,
> data can be decompressed directly to get rid of additional kworker
> scheduling overhead. Also, it makes no sense to apply synchronous
> decompression for such case.

Could you resend the whole patchset [v4 RESEND] as a whole? Or you
can use --in-reply-to to attach the original version.

Yet I'd suggest you could resend them all this time...

> 
> Signed-off-by: Huang Jianan <huangjianan at oppo.com>
> Signed-off-by: Guo Weichao <guoweichao at oppo.com>
> ---
>  fs/erofs/internal.h |  3 +++
>  fs/erofs/super.c    |  4 ++++
>  fs/erofs/zdata.c    | 16 +++++++++++++---
>  3 files changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 67a7ec945686..b817cb85d67b 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -70,6 +70,9 @@ struct erofs_sb_info {
>  
>  	/* pseudo inode to manage cached pages */
>  	struct inode *managed_cache;
> +
> +	/* decide whether to decompress synchronously */
> +	bool readahead_sync_decompress;
>  #endif	/* CONFIG_EROFS_FS_ZIP */
>  	u32 blocks;
>  	u32 meta_blkaddr;
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index d5a6b9b888a5..77819efe9b15 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -175,6 +175,10 @@ static int erofs_read_superblock(struct super_block *sb)
>  	sbi->root_nid = le16_to_cpu(dsb->root_nid);
>  	sbi->inos = le64_to_cpu(dsb->inos);
>  
> +#ifdef CONFIG_EROFS_FS_ZIP
> +	sbi->readahead_sync_decompress = false;
> +#endif

How about moving this stuff to erofs_default_options() as what we
did for max_sync_decompress_pages?

Thanks,
Gao Xiang