On Mon 15-08-16 08:34:07, Johannes Weiner wrote: > 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).
You are right. I am just wondering whether it matters. Nobody should see the id so nobody will be looking it up, no? > > 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? Yes, I will drop it. Thanks! -- Michal Hocko SUSE Labs
