The patch titled Subject: mm/memcg: non-hierarchical mode is deprecated has been added to the -mm tree. Its filename is mm-memcg-non-hierarchical-mode-is-deprecated.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-non-hierarchical-mode-is-deprecated.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-non-hierarchical-mode-is-deprecated.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Wei Yang <richard.weiyang@xxxxxxxxx> Subject: mm/memcg: non-hierarchical mode is deprecated After commit bef8620cd8e0 ("mm: memcg: deprecate the non-hierarchical mode"), we won't have a NULL parent except root_mem_cgroup. And this case is handled when (memcg == root). Link: https://lkml.kernel.org/r/20220403020833.26164-1-richard.weiyang@xxxxxxxxx Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Roman Gushchin <roman.gushchin@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 3 --- 1 file changed, 3 deletions(-) --- a/mm/memcontrol.c~mm-memcg-non-hierarchical-mode-is-deprecated +++ a/mm/memcontrol.c @@ -6588,9 +6588,6 @@ void mem_cgroup_calculate_protection(str return; parent = parent_mem_cgroup(memcg); - /* No parent means a non-hierarchical mode on v1 memcg */ - if (!parent) - return; if (parent == root) { memcg->memory.emin = READ_ONCE(memcg->memory.min); _ Patches currently in -mm which might be from richard.weiyang@xxxxxxxxx are mm-memcg-mz-already-removed-from-rb_tree-if-not-null.patch mm-memcg-set-memcg-after-css-verified-and-got-reference.patch mm-memcg-set-pos-explicitly-for-reclaim-and-reclaim.patch mm-memcg-move-generation-assignment-and-comparison-together.patch mm-memcg-non-hierarchical-mode-is-deprecated.patch mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order.patch mm-vmscan-reclaim-only-affects-managed_zones.patch mm-vmscan-make-sure-wakeup_kswapd-with-managed-zone.patch mm-vmscan-make-sure-wakeup_kswapd-with-managed-zone-v2.patch mm-vmscan-sc-reclaim_idx-must-be-a-valid-zone-index.patch