Messages in this thread | | | Date | Tue, 14 Aug 2012 15:00:53 +0400 | From | Glauber Costa <> | Subject | Re: [PATCH v2 06/11] memcg: kmem controller infrastructure |
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On 08/10/2012 09:27 PM, Kamezawa Hiroyuki wrote: >> +bool __memcg_kmem_new_page(gfp_t gfp, void *_handle, int order) >> > +{ >> > + struct mem_cgroup *memcg; >> > + struct mem_cgroup **handle = (struct mem_cgroup **)_handle; >> > + bool ret = true; >> > + size_t size; >> > + struct task_struct *p; >> > + >> > + *handle = NULL; >> > + rcu_read_lock(); >> > + p = rcu_dereference(current->mm->owner); >> > + memcg = mem_cgroup_from_task(p); >> > + if (!memcg_kmem_enabled(memcg)) >> > + goto out; >> > + >> > + mem_cgroup_get(memcg); >> > + > This mem_cgroup_get() will be a potentioal performance problem. > Don't you have good idea to avoid accessing atomic counter here ? > I think some kind of percpu counter or a feature to disable "move task" > will be a help. > >
I have just sent out a proposal to deal with this. I tried the trick of marking only the first charge and last uncharge, and it works quite alright at the cost of a bit test on most calls to memcg_kmem_charge.
Please let me know what you think.
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