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| author | Yosry Ahmed <yosryahmed@google.com> | 2022-03-23 00:40:10 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-23 01:57:02 +0300 |
| commit | a8c49af3be5f0b4e105ef678bcf14ef102c270be (patch) | |
| tree | 80f2c4728361aa90b71fec915c6c8b347f85f97e /Documentation | |
| parent | 086f694a75e1a283a11f9afa7bae258f30892b81 (diff) | |
| download | linux-a8c49af3be5f0b4e105ef678bcf14ef102c270be.tar.xz | |
memcg: add per-memcg total kernel memory stat
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
[yosryahmed@google.com: v2]
Link: https://lkml.kernel.org/r/20220203193856.972500-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20220201200823.3283171-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 5aa368d165da..69d7a6983f78 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1301,6 +1301,11 @@ PAGE_SIZE multiple when read back. Amount of memory used to cache filesystem data, including tmpfs and shared memory. + kernel (npn) + Amount of total kernel memory, including + (kernel_stack, pagetables, percpu, vmalloc, slab) in + addition to other kernel memory use cases. + kernel_stack Amount of memory allocated to kernel stacks. |