On 2/9/21 11:12 PM, Miaohe Lin wrote:
> We should not transfer the per-node surplus state when we do not cross the
> node in order to save some cpu cycles
>
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/hugetlb.c | 6 ++++++
> 1 file changed, 6 insertions(+)
Thanks,
I was going to comment that the usual case is migrating to another node
and old_nid != new_nid. However, this really is workload and system
configuration dependent. In any case, the quick check is worth potentially
saving a lock/unlock cycle.
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
--
Mike Kravetz
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index da347047ea10..4f2c92ddbca4 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -5632,6 +5632,12 @@ void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
> SetHPageTemporary(oldpage);
> ClearHPageTemporary(newpage);
>
> + /*
> + * There is no need to transfer the per-node surplus state
> + * when we do not cross the node.
> + */
> + if (new_nid == old_nid)
> + return;
> spin_lock(&hugetlb_lock);
> if (h->surplus_huge_pages_node[old_nid]) {
> h->surplus_huge_pages_node[old_nid]--;
>
