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McKenney" , Steven Rostedt , Masami Hiramatsu , Dennis Zhou , Tejun Heo , Christoph Lameter , Martin Liu , David Rientjes , christian.koenig@amd.com, Shakeel Butt , SeongJae Park , Michal Hocko , Johannes Weiner , Sweet Tea Dorminy , Lorenzo Stoakes , "Liam R . Howlett" , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , Christian Brauner , Wei Yang , David Hildenbrand , Miaohe Lin , Al Viro , linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, Yu Zhao , Roman Gushchin , Mateusz Guzik , Matthew Wilcox , Baolin Wang , Aboorva Devarajan Subject: [PATCH v15 0/3] mm: Reduce latency of OOM killer task selection Date: Tue, 13 Jan 2026 15:04:25 -0500 Message-Id: <20260113200428.30614-1-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.5 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-HE-Meta: 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tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Andrew, This series use the hierarchical tree counter approximation (hpcc) to implement the OOM killer task selection with a 2-pass algorithm. This is a latency reduction improvement of the OOM killer task selection. Testing the execution time of select_bad_process() with a single tail -f /dev/zero: AMD EPYC 9654 96-Core (2 sockets) Within a KVM, configured with 256 logical cpus. | precise sum | hpcc | ----------------------------------|-------------|----------| nr_processes=40 | 0.5 ms | 0.3 ms | nr_processes=10000 | 80.0 ms | 7.9 ms | Notable changes for v15: This series becomes a OOM killer latency improvement, rather than a bug fix. This series is based on v6.19-rc4, on top of the following three preparation series: https://lore.kernel.org/linux-mm/20251224173358.647691-1-mathieu.desnoyers@efficios.com/T/#t https://lore.kernel.org/linux-mm/20251224173810.648699-1-mathieu.desnoyers@efficios.com/T/#t https://lore.kernel.org/linux-mm/20260113194734.28983-1-mathieu.desnoyers@efficios.com/T/#t This series replaces v14, aimed at mm-new. Thanks, Matheu Cc: Andrew Morton Cc: "Paul E. McKenney" Cc: Steven Rostedt Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Dennis Zhou Cc: Tejun Heo Cc: Christoph Lameter Cc: Martin Liu Cc: David Rientjes Cc: christian.koenig@amd.com Cc: Shakeel Butt Cc: SeongJae Park Cc: Michal Hocko Cc: Johannes Weiner Cc: Sweet Tea Dorminy Cc: Lorenzo Stoakes Cc: "Liam R . Howlett" Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Christian Brauner Cc: Wei Yang Cc: David Hildenbrand Cc: Miaohe Lin Cc: Al Viro Cc: linux-mm@kvack.org Cc: linux-trace-kernel@vger.kernel.org Cc: Yu Zhao Cc: Roman Gushchin Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Baolin Wang Cc: Aboorva Devarajan Mathieu Desnoyers (3): lib: Introduce hierarchical per-cpu counters mm: Use hierarchical per-cpu counters for RSS tracking mm: Reduce latency of OOM killer task selection with 2-pass algorithm .../core-api/percpu-counter-tree.rst | 75 ++ fs/proc/base.c | 2 +- include/linux/mm.h | 46 +- include/linux/mm_types.h | 54 +- include/linux/oom.h | 11 +- include/linux/percpu_counter_tree.h | 367 ++++++++++ include/trace/events/kmem.h | 2 +- init/main.c | 2 + kernel/fork.c | 22 +- lib/Makefile | 1 + lib/percpu_counter_tree.c | 679 ++++++++++++++++++ mm/oom_kill.c | 84 ++- 12 files changed, 1296 insertions(+), 49 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 -- 2.39.5