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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: Re: [PATCH v9 1/2] lib: Introduce hierarchical per-cpu counters Message-Id: <20251122111336.56b060c86ff6ba41fe76bfd4@linux-foundation.org> In-Reply-To: References: <20251120210354.1233994-1-mathieu.desnoyers@efficios.com> <20251120210354.1233994-2-mathieu.desnoyers@efficios.com> <20251121100308.65b36af9e090a78a66144c6c@linux-foundation.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 3B39040017 X-Stat-Signature: g8orcw5dcciqxzgkz8b1krg665i3q31r X-Rspam-User: X-HE-Tag: 1763838820-302590 X-HE-Meta: U2FsdGVkX1/CgzR0TVt6nLRKn0Bzl/WsO470t1Y/IMscILCa4kG/0eeuOU2SG4c/wI+HW/z/jgSAiobCl7lJWOHRB43TEyl7J1cAJLQhR2MYswGXPlPKS8WDsW5eXjaUnFec6SRtlGZQPnCyGT75a378XKY0uXSUdGscDocLUvcpALDvIjwvRG1nUuJAsUg6no/cy6axq1/ZWum5cFomTnWvtjLVjoKJfX2YWum6aBNuRLdvp7GvZvTi5LwBbO3uqTabci/8NHc253aP4Ie9xUsWTVIgZexyziV02znbU0kNy1mEVlt4YDA5qmsFXv5HCQHGIQs3vQvHLFR96q/xgYS8jHIg0UAD2sdCKBtTmO10JeffOs6g7uq1wDKhWGuNwpCnjdsSsS7+2JNPF3b/rzUNscnGb2BcWuC/TZN4PtEt4dWJ2wWQsEuQxiNBQ+/lLm9JOH3BfBomIhsSNh87ctIwJIWcuJz4HNun+CsTkIafXZs4R9xwOp/8cTMmmpDggknKSlVnlms3RR5aYJNimQ8tqBCfdmc8ht2/DkX0caIb60aoy9AJYdooeZ2SAikFyJ8ox/DTOjIIxqIFmjWW+DbW2zNiAP0+qhtUNTrbwefDgLBCsdm3PoMMHpks9tX8ZpX3coulLpYiqN5yXcc//V1VkPVJXLv0K1D6aToc1NrdQ0cWIeFxgxvrFUB1qqhZIwfheZhoi+7upFcL0vvYcTJKThvljQRF6OAInHI3oNVFn44ci+pIDeljOZmgeyhSnTwdgnn3JkItM7MchwHjP9LBvkW7OAQ8ihPzRERl/5EJLvC/9UpFgdjSW1K66mUdyyQV2Ogk2QaejrXHsI4a/eA3Qzo59mgljGX/wsAgTovPpGvOT3sXl/Ur7EdVeRX2DgMdhsvbcNEqVJTkuwGGzRkLSw5B8/UU2NVwH6zVtPr6hFwkYvgerA0dCTh2aXpb2DVnJkzUm2raQvSHX3q HL8KV8a5 fTwW6MSy1lMcnqg3mnDsRZkh6CO9Qq19isjdFK7a2WzjpJOo/tyVUuiVUSOWrVMe+ZaoKWExbTBkhE2SyRcz3ouuxujnQkM4UvXVKcozSDKj99GmPdzY70GPRys7bToZHdUpk9Ln7Jmd0YaLoNXTyn1cJkr77aCOE4HO2TnwzCWQ2fLkHiLw0/V9NHhCqYxpLElUoyRRprMKQz9OV8hnKnn9K/Xhnkzr14H74LmKwAMUh8HYZWazAvExCi2W1fn8xLxJ4vDwwa7Up7ncugpk1PmwgkhOzg+QJ9r8Ri1YiuDXLGk0mqRAryY0PBd1SumujjK/DRrUPAwPWDsOsIczKUPm3pnEFOGCtZnwqMvoYVff0QOu9ouKPIfCQpCCxipdDoMWH X-Bogosity: Ham, 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: On Sat, 22 Nov 2025 12:15:02 -0500 Mathieu Desnoyers wrote: > > > >> include/linux/percpu_counter_tree.h | 239 +++++++++++++++ > >> init/main.c | 2 + > >> lib/Makefile | 1 + > >> lib/percpu_counter_tree.c | 443 ++++++++++++++++++++++++++++ > >> 4 files changed, 685 insertions(+) > >> create mode 100644 include/linux/percpu_counter_tree.h > >> create mode 100644 lib/percpu_counter_tree.c > > > > An in-kernel test suite would be great. Like lib/*test*.c or > > tools/testing/. > > I'll keep a note to port the tests from my userspace librseq > percpu counters feature branch to the kernel. I did not do it > initially because I wanted to see if the overall approach was > deemed interesting for the kernel. It deems interesting to me - certainly seems useful in addressing some nasty problems. If it hasn't been massacred by reviewers, please poke me in a week or so and I'll look at giving it some exposure in mm.git's mm-new branch (which isn't included in linux-next).