[RFC PATCH v8 0/2] mm: Fix OOM killer inaccuracy on large many-core systems

[Mathieu Desnoyers]

Introduce hierarchical per-cpu counters and use them for rss tracking to
fix the per-mm RSS tracking which has become too inaccurate for OOM
killer purposes on large many-core systems.

The approach proposed here is to replace this by the hierarchical
per-cpu counters, which bounds the inaccuracy based on the system
topology with O(N*logN).

Relevant delta since v7: Initialize the subsystem earlier in
start_kernel() so it is ready before any mm is created. Introduce and
use a precise sum positive API to cover the scenario where an unlucky
precise sum iteration happens concurrently with a sequence of counter
updates that makes it observe a negative sum.

Testing and feedback are welcome!

Thanks,

Mathieu

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Martin Liu <liumartin@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: christian.koenig@xxxxxxx
Cc: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Sweet Tea Dorminy <sweettea@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: "Liam R . Howlett" <liam.howlett@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: linux-trace-kernel@xxxxxxxxxxxxxxx
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Mateusz Guzik <mjguzik@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Aboorva Devarajan <aboorvad@xxxxxxxxxxxxx>

Mathieu Desnoyers (2):
  lib: Introduce hierarchical per-cpu counters
  mm: Fix OOM killer inaccuracy on large many-core systems

 include/linux/mm.h                  |  10 +-
 include/linux/mm_types.h            |   4 +-
 include/linux/percpu_counter_tree.h | 217 +++++++++++++++
 include/trace/events/kmem.h         |   2 +-
 init/main.c                         |   2 +
 kernel/fork.c                       |  32 ++-
 lib/Makefile                        |   1 +
 lib/percpu_counter_tree.c           | 392 ++++++++++++++++++++++++++++
 8 files changed, 641 insertions(+), 19 deletions(-)
 create mode 100644 include/linux/percpu_counter_tree.h
 create mode 100644 lib/percpu_counter_tree.c

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2.39.5