On Fri, 24 Apr 2020, Roman Gushchin wrote: > > The patch seems to only use it for setup and debugging? It is used for > > every "accounted" allocation???? Where? And what is an "accounted" > > allocation? > > > > > > Please, take a look at the whole series: > https://lore.kernel.org/linux-mm/20200422204708.2176080-1-guro@xxxxxx/T/#t > > I'm sorry, I had to cc you directly for the whole thing. Your feedback > will be highly appreciated. > > It's used to calculate the offset of the memcg pointer for every slab > object which is charged to a memory cgroup. So it must be quite hot. Ahh... Thanks. I just looked at it. You need this because you have a separate structure attached to a page that tracks membership of the slab object to the cgroup. This is used to calculate the offset into that array.... Why do you need this? Just slap a pointer to the cgroup as additional metadata onto the slab object. Is that not much simpler, safer and faster?
