Re: [PATCH v2 01/12] mm/page_isolation: prefer the node of the source page

[Vlastimil Babka]

On 5/27/20 8:44 AM, js1304@xxxxxxxxx wrote:
> From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> 
> For locality, it's better to migrate the page to the same node
> rather than the node of the current caller's cpu.

Should be, yeah.

> Acked-by: Roman Gushchin <guro@xxxxxx>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
>  mm/page_isolation.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 2c11a38..7df89bd 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -300,5 +300,7 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
>  
>  struct page *alloc_migrate_target(struct page *page, unsigned long private)
>  {
> -	return new_page_nodemask(page, numa_node_id(), &node_states[N_MEMORY]);
> +	int nid = page_to_nid(page);
> +
> +	return new_page_nodemask(page, nid, &node_states[N_MEMORY]);

I wonder why this and others uses node_states[N_MEMORY] and not just NULL. But
maybe that's addressed later.

>  }
>