Re: [PATCH v3 05/35] mm: introduce slabobj_ext to support slab object extensions

On Mon, Feb 12, 2024 at 2:14 PM Kees Cook [off-list ref] wrote:

On Mon, Feb 12, 2024 at 01:38:51PM -0800, Suren Baghdasaryan wrote:

quoted

Currently slab pages can store only vectors of obj_cgroup pointers in
page->memcg_data. Introduce slabobj_ext structure to allow more data
to be stored for each slab object. Wrap obj_cgroup into slabobj_ext
to support current functionality while allowing to extend slabobj_ext
in the future.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>

It looks like this doesn't change which buckets GFP_KERNEL_ACCOUNT comes
out of, is that correct? I'd love it if we didn't have separate buckets
so GFP_KERNEL and GFP_KERNEL_ACCOUNT came from the same pools (so that
the randomized pools would cover GFP_KERNEL_ACCOUNT ...)

This should not affect KMEM accounting in any way. We are simply
changing the vector of obj_cgroup objects to hold complex objects
which can contain more fields in addition to the original obj_cgroup
(in our case it's the codetag reference).
Unless I misunderstood your question?

Regardless:

Reviewed-by: Kees Cook <redacted>

--
Kees Cook