On Wed 15-11-17 01:32:16, Yang Shi wrote: > > > On 11/14/17 1:39 AM, Michal Hocko wrote: > >On Tue 14-11-17 03:10:22, Yang Shi wrote: > >> > >> > >>On 11/9/17 5:54 AM, Michal Hocko wrote: > >>>[Sorry for the late reply] > >>> > >>>On Tue 31-10-17 11:12:38, Jan Kara wrote: > >>>>On Tue 31-10-17 00:39:58, Yang Shi wrote: > >>>[...] > >>>>>I do agree it is not fair and not neat to account to producer rather than > >>>>>misbehaving consumer, but current memcg design looks not support such use > >>>>>case. And, the other question is do we know who is the listener if it > >>>>>doesn't read the events? > >>>> > >>>>So you never know who will read from the notification file descriptor but > >>>>you can simply account that to the process that created the notification > >>>>group and that is IMO the right process to account to. > >>> > >>>Yes, if the creator is de-facto owner which defines the lifetime of > >>>those objects then this should be a target of the charge. > >>> > >>>>I agree that current SLAB memcg accounting does not allow to account to a > >>>>different memcg than the one of the running process. However I *think* it > >>>>should be possible to add such interface. Michal? > >>> > >>>We do have memcg_kmem_charge_memcg but that would require some plumbing > >>>to hook it into the specific allocation path. I suspect it uses kmalloc, > >>>right? > >> > >>Yes. > >> > >>I took a look at the implementation and the callsites of > >>memcg_kmem_charge_memcg(). It looks it is called by: > >> > >>* charge kmem to memcg, but it is charged to the allocator's memcg > >>* allocate new slab page, charge to memcg_params.memcg > >> > >>I think this is the plumbing you mentioned, right? > > > >Maybe I have misunderstood, but you are using slab allocator. So you > >would need to force it to use a different charging context than current. > > Yes. > > >I haven't checked deeply but this doesn't look trivial to me. > > I agree. This is also what I explained to Jan and Amir in earlier > discussion. And I also agree. But the fact that it is not trivial does not mean that it should not be done... Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
