Re: [v2 PATCH 1/2] mm: swap: check if swap backing device is congested or not

[Tim Chen]

On 12/20/18 4:21 PM, Yang Shi wrote:

> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -538,11 +538,17 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
>  	bool do_poll = true, page_allocated;
>  	struct vm_area_struct *vma = vmf->vma;
>  	unsigned long addr = vmf->address;
> +	struct inode *inode = si->swap_file->f_mapping->host;
>  
>  	mask = swapin_nr_pages(offset) - 1;
>  	if (!mask)
>  		goto skip;
>  
> +	if (si->flags & (SWP_BLKDEV | SWP_FS)) {

Maybe move the inode dereference here: 

		inode = si->swap_file->f_mapping->host;

> +		if (inode_read_congested(inode))
> +			goto skip;
> +	}
> +

Thanks.

Tim