[PATCH v19 0/6] Hierarchical Percpu Counters for RSS

From: Mathieu Desnoyers

Date: Thu Jul 02 2026 - 15:40:07 EST


Hi Andrew,

Here is the hierarchical percpu counters series rebased on top of
v7.2-rc1. It includes small bootup fixes which were needed to fix
bootup sequence on specific architectures.

This aims at replacing the prior version of the series you had
in mm.

As a reminder, the goal here is to provide more precise RSS counters
through /proc.

Thanks,

Mathieu

Mathieu Desnoyers (6):
lib: introduce hierarchical per-cpu counters
lib: test hierarchical per-cpu counters
mm: improve RSS counter approximation accuracy for proc interfaces
mm: reorder mm_struct flexible array to place mm_cpumask first
init: move percpu_counter_tree_subsystem_init() earlier in boot
lib: inline percpu_counter_tree_items_size with boot-safety sentinel

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-kernel@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: 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>
Cc: David Carlier <devnexen@xxxxxxxxx>
Cc: Josh Law <objecting@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>

.../core-api/percpu-counter-tree.rst | 75 ++
include/linux/mm.h | 20 +-
include/linux/mm_types.h | 65 +-
include/linux/percpu_counter_tree.h | 387 ++++++++++
include/trace/events/kmem.h | 2 +-
init/main.c | 2 +
kernel/fork.c | 24 +-
lib/Kconfig | 12 +
lib/Makefile | 1 +
lib/percpu_counter_tree.c | 694 ++++++++++++++++++
lib/tests/Makefile | 2 +
lib/tests/percpu_counter_tree_kunit.c | 399 ++++++++++
12 files changed, 1651 insertions(+), 32 deletions(-)
create mode 100644 Documentation/core-api/percpu-counter-tree.rst
create mode 100644 include/linux/percpu_counter_tree.h
create mode 100644 lib/percpu_counter_tree.c
create mode 100644 lib/tests/percpu_counter_tree_kunit.c

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2.43.0