Messages in this thread | | | Date | Fri, 4 Feb 2022 14:22:40 -0500 | From | Johannes Weiner <> | Subject | Re: [PATCH v2] memcg: add per-memcg total kernel memory stat |
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On Thu, Feb 03, 2022 at 07:38:56PM +0000, Yosry Ahmed wrote: > Currently memcg stats show several types of kernel memory: > kernel stack, page tables, sock, vmalloc, and slab. > However, there are other allocations with __GFP_ACCOUNT > (or supersets such as GFP_KERNEL_ACCOUNT) that are not accounted > in any of those stats, a few examples are: > - various kvm allocations (e.g. allocated pages to create vcpus) > - io_uring > - tmp_page in pipes during pipe_write() > - bpf ringbuffers > - unix sockets > > Keeping track of the total kernel memory is essential for the ease of > migration from cgroup v1 to v2 as there are large discrepancies between > v1's kmem.usage_in_bytes and the sum of the available kernel memory stats > in v2. Adding separate memcg stats for all __GFP_ACCOUNT kernel > allocations is an impractical maintenance burden as there a lot of those > all over the kernel code, with more use cases likely to show up in the > future. > > Therefore, add a "kernel" memcg stat that is analogous to kmem > page counter, with added benefits such as using rstat infrastructure > which aggregates stats more efficiently. Additionally, this provides a > lighter alternative in case the legacy kmem is deprecated in the future > > Signed-off-by: Yosry Ahmed <yosryahmed@google.com> > Acked-by: Shakeel Butt <shakeelb@google.com> > Acked-by: Johannes Weiner <hannes@cmpxchg.org> > Reported-by: kernel test robot <lkp@intel.com>
Looks good, thanks Yosry!
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