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Sat, 31 Oct 2026 00:47:46 +0000 X-Mizu-Trace-ID: 5b6af64fea02a9fd 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 3/5] memcg: use high_work for kernel threads From: Muchun Song In-Reply-To: <20261030205418.341214-4-shakeel.butt@linux.dev> Date: Sat, 31 Oct 2026 08:47:30 +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> <20261030205418.341214-4-shakeel.butt@linux.dev> To: Shakeel Butt X-Mailer: Apple Mail (2.3901.100.1.1.12) X-Rspamd-Queue-Id: CB288C0003 X-Stat-Signature: xhs193r6kiozz3oqogcujczjjb5xfwau X-Rspamd-Server: rspam04 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-HE-Tag: 1793407667-405717 X-HE-Meta: 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 /mOLNiW9 HLuCKg1dIaOsn5v5MGOvsFfDB3HLt956wFuqCpV3oSA0cyNW47wbpADZI9E0E6S8HR7wtFL9S+l+HDhhbj2XAWTPcAxE89ISGCXDjSn0DPAAh6YNh+1B9Ea+Fi8fzXsfNIdm/Wqk/cH3hj9vs4wAXUMkczGAfP0/tzOONCoKMPdLiRzSkfERhCCYYCPU3Csut6nRWj1gvusP+h57l2tcdO8kQ3/90ZSpKIf562CQm8eLZKkEkcOf0PHsw12AONd6ZiYrMZMdbwR2qbLh4p/JxA55kHQ6gdTtjD2XJt3wK8bNDYjW2ggej+QhW4mpUYXmtGUbwqfRwPjaFW8+H795JLrEpzJcdmfCTgAvWbqUrjpGZdLYn4FnfHZx72P3rrU4V/88dbDAWZkk9LRc= 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: > > Kernel threads never return to userspace, so deferred memory.high > reclaim does not run. Reclaim and throttling during a charge can also > delay work they do for other tasks. > > Treat kernel threads like interrupts. Queue high_work for the first > cgroup over memory.high and skip reclaim and throttling in the charging > thread. > > User workers created by create_io_thread() and vhost_task_create() keep > their current behavior. Vhost kernel threads use the new path, even when > they borrow the owner's mm. > > The worker requests a fixed batch of pages each time. A fast allocator > can keep usage well above memory.high. Kernel threads also skip > memory.swap.high throttling and its high-event reporting. 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.