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Fri, 31 Oct 2025 09:48:56 -0700 (PDT) Received: from localhost.localdomain ([124.156.216.125]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7a7db0a26f2sm2755863b3a.41.2025.10.31.09.48.49 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 31 Oct 2025 09:48:55 -0700 (PDT) From: Lance Yang To: mhocko@suse.com Cc: akpm@linux-foundation.org, andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, hannes@cmpxchg.org, inwardvessel@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, martin.lau@kernel.org, memxor@gmail.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, song@kernel.org, surenb@google.com, tj@kernel.org, Lance Yang Subject: Re: [PATCH v2 00/23] mm: BPF OOM Date: Sat, 1 Nov 2025 00:48:44 +0800 Message-ID: <20251031164844.27060-1-ioworker0@gmail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: E340380004 X-Rspamd-Server: rspam03 X-Stat-Signature: ioqqk9h9b3hs6qks5j9sn1634ien7m57 X-HE-Tag: 1761929337-955249 X-HE-Meta: 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 65zeLhwS zzs8yRtfk7KrIMRQdmJWjPinxlm46UlASy+pNwHn6qzfMgyQc+ub2kgQoPmir8HITjFYBCUuPV3nhatamaIwX+6vvh9zdvhLa4Qi2dZQMWPKDeyYhvjF7D7RaaiQTtwU5NcuPOxppmjjPdJC3cmJJM36rkD03XGaA72wI4Xfg3WqqW8bgnRaX3ccCRVNFISOv+qogjsSEec3cLyXcm4VTzQWUqVHcN+b08qQWznEcZJ8x97stERgyRxbOQSCUYqtWYfAQOFKp/clqSY/dXsfOk9aUcc+UM9fatWk7/MGTblwxusp7yjh/+90xRFUn8r6BNAZq7z0P1sLzxpaLRBKRucC2ytwNYeLu8wiTzRaMhXlrSZ6Y5rNk4V/usplu24Hrg+swGuB9G4B7ckg= 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: From: Lance Yang On Fri, 31 Oct 2025 10:31:36 +0100, Michal Hocko wrote: > On Mon 27-10-25 16:17:03, Roman Gushchin wrote: > > The second part is related to the fundamental question on when to > > declare the OOM event. It's a trade-off between the risk of > > unnecessary OOM kills and associated work losses and the risk of > > infinite trashing and effective soft lockups. In the last few years > > several PSI-based userspace solutions were developed (e.g. OOMd [3] or > > systemd-OOMd [4]). The common idea was to use userspace daemons to > > implement custom OOM logic as well as rely on PSI monitoring to avoid > > stalls. In this scenario the userspace daemon was supposed to handle > > the majority of OOMs, while the in-kernel OOM killer worked as the > > last resort measure to guarantee that the system would never deadlock > > on the memory. But this approach creates additional infrastructure > > churn: userspace OOM daemon is a separate entity which needs to be > > deployed, updated, monitored. A completely different pipeline needs to > > be built to monitor both types of OOM events and collect associated > > logs. A userspace daemon is more restricted in terms on what data is > > available to it. Implementing a daemon which can work reliably under a > > heavy memory pressure in the system is also tricky. > > I do not see this part addressed in the series. Am I just missing > something or this will follow up once the initial (plugging to the > existing OOM handling) is merged? I noticed that this thread only shows up to patch 10/23. The subsequent patches (11-23) appear to be missing ... This might be why we're not seeing the userspace OOM daemon part addressed. I suspect the relevant code is likely in those subsequent patches. Cheers, Lance