On Mon, Aug 15, 2022 at 8:42 AM Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote: > > On Mon, Aug 15, 2022 at 8:31 AM Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > > > On Mon, Aug 15, 2022 at 06:46:46AM -0700, Yosry Ahmed wrote: > > > Yeah I understand this much, what I don't understand is why we charge > > > the zswap memory through objcg (thus tying it to memcg kmem charging) > > > rather than directly through memcg. > > > > The charged quantities are smaller than a page, so we have to use the > > byte interface. > > > > The byte interface (objcg) was written for slab originally, hence the > > link to the kmem option. But note that CONFIG_MEMCG_KMEM is no longer > > a user-visible option, and for all intents and purposes a fixed part > > of CONFIG_MEMCG. > > > > (There is the SLOB quirk. But I'm not sure anybody uses slob, let > > alone slob + memcg.) > > Thanks for the clarification, it makes sense to use the byte interface > here for this, and thanks for pointing out that CONFIC_MEMCG_KMEM is > not part of CONFIG_MEMCG. > > One more question :) memcg kmem charging can still be disabled even > with !CONFIG_MEMCG_KMEM, right? In this case zswap charging will also > be off, which seems like an unintended side effect, right? memcg kmem charging can still be disabled even with CONFIG_MEMCG_KMEM***
