[PATCH 4/4] mm: remove direct calling of migration

Vlastimil Babka
Mon, 27 Jul 2015 13:58:09 -0000

On 07/13/2015 10:35 AM, Gioh Kim wrote:
> From: Gioh Kim <gurugio at hanmail.net>
>
> Migration is completely generalized so that migrating mobile page
> is processed with lru-pages in move_to_new_page.
>
> Signed-off-by: Gioh Kim <gioh.kim at lge.com>
> Acked-by: Rafael Aquini <aquini at redhat.com>

Why not just fold this to Patch 3? You already modify this hunk there,
and prior to patch 3, the hunk was balloon-pages specific. You made it
look generic only to remove it, which is unneeded code churn and I don't
think it adds anything wrt e.g. bisectability.

> ---
>   mm/migrate.c | 15 ---------------
>   1 file changed, 15 deletions(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 53f0081d..e6644ac 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -844,21 +844,6 @@ static int __unmap_and_move(struct page *page, struct
page *newpage,
>   		}
>   	}
>
> -	if (unlikely(mobile_page(page))) {
> -		/*
> -		 * A mobile page does not need any special attention from
> -		 * physical to virtual reverse mapping procedures.
> -		 * Skip any attempt to unmap PTEs or to remap swap cache,
> -		 * in order to avoid burning cycles at rmap level, and perform
> -		 * the page migration right away (proteced by page lock).
> -		 */
> -		lock_page(newpage);
> -		rc = page->mapping->a_ops->migratepage(page->mapping,
> -						       newpage, page, mode);
> -		unlock_page(newpage);
> -		goto out_unlock;
> -	}
> -
>   	/*
>   	 * Corner case handling:
>   	 * 1. When a new swap-cache page is read into, it is added to the LRU
>