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[34.90.50.93]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-658b4691d0asm7521455a12.18.2026.02.01.21.39.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 01 Feb 2026 21:39:52 -0800 (PST) Date: Mon, 2 Feb 2026 05:39:48 +0000 From: Matt Bobrowski To: Roman Gushchin Cc: bpf@vger.kernel.org, Michal Hocko , Alexei Starovoitov , Shakeel Butt , JP Kobryn , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Suren Baghdasaryan , Johannes Weiner , Andrew Morton Subject: Re: [PATCH bpf-next v3 10/17] mm: introduce bpf_task_is_oom_victim() kfunc Message-ID: References: <20260127024421.494929-1-roman.gushchin@linux.dev> <20260127024421.494929-11-roman.gushchin@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260127024421.494929-11-roman.gushchin@linux.dev> X-Rspamd-Server: rspam11 X-Stat-Signature: q35bacagk99bf73irefeqj63xisqjrkj X-Rspam-User: X-Rspamd-Queue-Id: 0BB7210000C X-HE-Tag: 1770010794-739397 X-HE-Meta: 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 3pMNcrBm 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 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 Mon, Jan 26, 2026 at 06:44:13PM -0800, Roman Gushchin wrote: > Export tsk_is_oom_victim() helper as a BPF kfunc. > It's very useful to avoid redundant oom kills. > > Signed-off-by: Roman Gushchin > Suggested-by: Michal Hocko > --- > mm/oom_kill.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 8f63a370b8f5..53f9f9674658 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -1381,10 +1381,24 @@ __bpf_kfunc int bpf_out_of_memory(struct mem_cgroup *memcg__nullable, > return ret; > } > > +/** > + * bpf_task_is_oom_victim - Check if the task has been marked as an OOM victim > + * @task: task to check > + * > + * Returns true if the task has been previously selected by the OOM killer > + * to be killed. It's expected that the task will be destroyed soon and some > + * memory will be freed, so maybe no additional actions required. > + */ > +__bpf_kfunc bool bpf_task_is_oom_victim(struct task_struct *task) > +{ > + return tsk_is_oom_victim(task); > +} Why not just do a direct memory read (i.e., task->signal->oom_mm) within the BPF program? I'm not quite convinced that a BPF kfunc wrapper for something like tsk_is_oom_victim() is warranted as you can literally achieve the same semantics without one.