Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> writes:
> For the worst case (MAX_NUMNODES=1024), the node_demotion structure can
> consume 32k bytes, which appears too large, so we can change to allocate
> node_demotion dynamically at initialization time. Meanwhile allocating
> the target demotion nodes array dynamically to select a suitable size
> according to the MAX_NUMNODES.
>
> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
> ---
> mm/migrate.c | 38 +++++++++++++++++++++++++++++---------
> 1 file changed, 29 insertions(+), 9 deletions(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 126e9e6..0145b38 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1152,10 +1152,11 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
> #define DEFAULT_DEMOTION_TARGET_NODES 15
> struct demotion_nodes {
> unsigned short nr;
> - short nodes[DEFAULT_DEMOTION_TARGET_NODES];
> + short nodes[];
> };
>
> -static struct demotion_nodes node_demotion[MAX_NUMNODES] __read_mostly;
> +static struct demotion_nodes *node_demotion[MAX_NUMNODES] __read_mostly;
> +static unsigned short target_nodes_max;
I think we can use something as below,
#if MAX_NUMNODES < DEFAULT_DEMOTION_TARGET_NODES
#define DEMOTION_TARGET_NODES (MAX_NUMNODES - 1)
#else
#define DEMOTION_TARGET_NODES DEFAULT_DEMOTION_TARGET_NODES
#endif
static struct demotion_nodes *node_demotion;
Then we can allocate nr_node_ids * sizeof(struct demotion_nodes) for node_demotion.
Best Regards,
Huang, Ying
[snip]
