Hello Tim,
On Tue, Feb 09, 2021 at 12:29:47PM -0800, Tim Chen wrote:
> @@ -6849,7 +6850,9 @@ static void uncharge_page(struct page *page, struct
> uncharge_gather *ug)
> * exclusive access to the page.
> */
>
> - if (ug->memcg != page_memcg(page)) {
> + if (ug->memcg != page_memcg(page) ||
> + /* uncharge batch update soft limit tree on a node basis */
> + (ug->dummy_page && ug->nid != page_to_nid(page))) {
The fix makes sense to me.
However, unconditionally breaking up the batch by node can
unnecessarily regress workloads in cgroups that do not have a soft
limit configured, and cgroup2 which doesn't have soft limits at
all. Consider an interleaving allocation policy for example.
Can you please further gate on memcg->soft_limit != PAGE_COUNTER_MAX,
or at least on !cgroup_subsys_on_dfl(memory_cgrp_subsys)?
Thanks
