Hi Michal, thanks for doing this. There is only one issue I can see: On Fri, Aug 12, 2016 at 11:56:17AM +0200, Michal Hocko wrote: > @@ -4171,17 +4211,27 @@ static struct mem_cgroup *mem_cgroup_alloc(void) > if (!memcg) > return NULL; > > + memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL, > + 1, MEM_CGROUP_ID_MAX, > + GFP_KERNEL); > + if (memcg->id.id < 0) > + goto out_free; > + > memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu); > if (!memcg->stat) > - goto out_free; > + goto out_idr; > > if (memcg_wb_domain_init(memcg, GFP_KERNEL)) > goto out_free_stat; > > + idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
This publishes the memcg object too early. Before 4.5, the memcg is not fully initialized in mem_cgroup_alloc(). You have to move the idr_replace() down to that function (and idr_remove() on free_out). > return memcg; > > out_free_stat: > free_percpu(memcg->stat); > +out_idr: > + if (memcg->id.id > 0) > + idr_remove(&mem_cgroup_idr, memcg->id.id); The > 0 check seems unnecessary, no?
