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Sat, 31 Oct 2026 00:48:38 +0000 X-Mizu-Trace-ID: 8d4b375cdaecd94c X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset=us-ascii X-Archived-By: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3901.100.1.1.12\)) Subject: Re: [PATCH v2 4/5] memcg: use high_work for remote charges From: Muchun Song In-Reply-To: <20261030205418.341214-5-shakeel.butt@linux.dev> Date: Sat, 31 Oct 2026 08:48:21 +0800 Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Tejun Heo , Harry Yoo , Meta kernel team , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko Content-Transfer-Encoding: 7bit Message-Id: References: <20261030205418.341214-1-shakeel.butt@linux.dev> <20261030205418.341214-5-shakeel.butt@linux.dev> To: Shakeel Butt X-Mailer: Apple Mail (2.3901.100.1.1.12) X-Rspamd-Queue-Id: EB98840002 X-Stat-Signature: oktnhphxzb6oz5xr9m84ibgdnruduztd X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1793407719-477596 X-HE-Meta: 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 B5GkS9fT FcpLTTXjBFr4Zo8aV/p8DWp5onQ9KC/bmIhqf732EvT6R6hHp9Cg+Fza2DBBIRkwkGWEPSh8M4uAC+ueYZXBcptzSYpARPu75cRbB+7ieudrw168eF0gQQoRlyqYyrntmr3sv58JrMUdEm9Qy3iYIXh0ACrTx+l+TiecJEpyG2MnKFgptHcjEzFFaISTBJ/at+skYXqAWIhafi8rrVZIOWdZpFZ+1G3FTkXjzN6DO/Eryquad7oZ2YnXrW7CxApfv77vRBTaZj6OnW4kU5dqtG9zT+d8r2f3yIX0VkOdnOBRK/hil+BoPeJSqdhLUM6psur+/5S0jDEglExvQktz9RWRgM+QrwmRQqqXnzdhbPufYWQcqDU49OjLvyxkJ/g9o/eYt6o0f2a9M+XE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 > On Oct 31, 2026, at 04:54, Shakeel Butt wrote: > > Some charges go to a cgroup outside the current mm's cgroup and its > ancestors. The high handler uses current->mm, so it cannot handle these > overages. Filesystem notifications and remote page faults can take > this path. > > Use mm_match_cgroup() before checking the high limits. If it does not > match, use high_work instead of recording task overage or doing > synchronous reclaim and throttling. Charges to the current mm's cgroup > or one of its ancestors keep their current handling. Tasks without an > mm also use the worker. > > Like kernel threads, remote chargers skip memory.swap.high throttling > and its high-event reporting, and a fast allocator can outrun the worker. > The memory.max and memory.swap.max checks stay the same. > > Suggested-by: Tejun Heo > Signed-off-by: Shakeel Butt > Acked-by: Michal Hocko Acked-by: Muchun Song Thanks.