Messages in this thread |  | | From | Usama Arif <> | | Subject | Re: [PATCH v6 31/33] mm: memcontrol: convert objcg to be per-memcg per-node type | | Date | Fri, 6 Mar 2026 12:29:28 -0800 |
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On Thu, 5 Mar 2026 19:52:49 +0800 Qi Zheng <qi.zheng@linux.dev> wrote:
> From: Qi Zheng <zhengqi.arch@bytedance.com> > > Convert objcg to be per-memcg per-node type, so that when reparent LRU > folios later, we can hold the lru lock at the node level, thus avoiding > holding too many lru locks at once. > > Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> > Acked-by: Shakeel Butt <shakeel.butt@linux.dev> > --- > include/linux/memcontrol.h | 23 +++++------ > include/linux/sched.h | 2 +- > mm/memcontrol.c | 79 +++++++++++++++++++++++--------------- > 3 files changed, 62 insertions(+), 42 deletions(-) >
[...]
> @@ -4087,7 +4100,13 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css) > xa_store(&mem_cgroup_private_ids, memcg->id.id, memcg, GFP_KERNEL); > > return 0; > -free_shrinker: > +free_objcg: > + for_each_node(nid) { > + struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid]; > + > + if (pn && pn->orig_objcg) > + obj_cgroup_put(pn->orig_objcg);
Is it possible that you might call obj_cgroup_put twice on the same cgroup?
If css_create fails, css_free_rwork_fn is queued, which ends up calling mem_cgroup_css_free which calls obj_cgroup_put again?
Maybe adding pn->orig_objcg = NULL overhere after obj_cgroup_put is enough to prevent the double put from causing issues?
> + } > free_shrinker_info(memcg); > offline_kmem: > memcg_offline_kmem(memcg); > -- > 2.20.1 > >
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