Re: [PATCH v20 0/6] Hierarchical Percpu Counters for RSS

[Mathieu Desnoyers]

On 2026-07-23 13:53, Mathieu Desnoyers wrote:
> On 2026-07-07 09:15, Mathieu Desnoyers wrote:
> > Hi Andrew,
> >
> > Here is the hierarchical percpu counters series rebased on top of
> > v7.2-rc2. It includes small bootup fixes which were needed to fix
> > bootup sequence on specific architectures, and a rename of the
> > test config option to include "KUNIT_".
> >
> > 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.
>
> Hello,
>
> Just a gentle ping for feedback whenever it's convenient.

Hi Andrew,

Can you pick this up after the upcoming merge window ?

That's of course assuming this is solving an issue which is
still relevant.

If there is no interest in solving this issue anymore, kindly
let me know and I'll drop this series.

Thanks,

Mathieu

> Thanks,
>
> Mathieu
>
> > 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


--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com