On Tue,  9 Oct 2018 14:47:32 -0400 Johannes Weiner <[email protected]> wrote:

> --- a/mm/workingset.c
> +++ b/mm/workingset.c
> @@ -378,11 +378,17 @@ void workingset_update_node(struct xa_node *node)
>        * as node->private_list is protected by the i_pages lock.
>        */
>       if (node->count && node->count == node->nr_values) {
> -             if (list_empty(&node->private_list))
> +             if (list_empty(&node->private_list)) {
>                       list_lru_add(&shadow_nodes, &node->private_list);
> +                     __inc_lruvec_page_state(virt_to_page(node),
> +                                             WORKINGSET_NODES);
> +             }
>       } else {
> -             if (!list_empty(&node->private_list))
> +             if (!list_empty(&node->private_list)) {
>                       list_lru_del(&shadow_nodes, &node->private_list);
> +                     __dec_lruvec_page_state(virt_to_page(node),
> +                                             WORKINGSET_NODES);
> +             }
>       }
>  }

A bit worried that we're depending on the caller's caller to have
disabled interrupts to avoid subtle and rare errors.

Can we do this?

--- a/mm/workingset.c~mm-workingset-add-vmstat-counter-for-shadow-nodes-fix
+++ a/mm/workingset.c
@@ -377,6 +377,8 @@ void workingset_update_node(struct radix
         * already where they should be. The list_empty() test is safe
         * as node->private_list is protected by the i_pages lock.
         */
+       WARN_ON_ONCE(!irqs_disabled()); /* For __inc_lruvec_page_state */
+
        if (node->count && node->count == node->exceptional) {
                if (list_empty(&node->private_list)) {
                        list_lru_add(&shadow_nodes, &node->private_list);
_

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