Re: [PATCH v4 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one

[Oscar Salvador]

On Wed, Jan 13, 2021 at 01:22:04PM +0800, Muchun Song wrote:
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 4385f2fb5d18..a6631c4eb6a6 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1279,6 +1279,12 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
>  		return -ENOSYS;
>  	}
>  
> +	if (page_count(hpage) == 1) {
> +		/* page was freed from under us. So we are done. */
> +		putback_active_hugepage(hpage);
> +		return MIGRATEPAGE_SUCCESS;
> +	}
> +

I was a bit puzzled as why we did not go to the "goto" block that already does
this, but then I saw the put_new_page/new_hpage handlind further down.
It could be re-arranged but out of scope, so:

Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>


-- 
Oscar Salvador
SUSE L3