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b=SdogaS6+LIPuo6XrzKc4ZRQ+7witXcilXONT3n7r34/LM37IrHGLhCySHeXGsVOMr xwTZHZLO2TDfb6JCiCWxILKwZgSqnUMtTTtzSK56q9qT2QvNCqx5o1F7ZvZQuLbnPV aYLwOJa/gdB5jSIQ/P/QZMZ7W4E9pza3j+jeiz4ILX9kLZpkGseRSIbCrQFJH+2MFg sqilqCC5FPu1IqNFqd52bdulInQzvHIrTN1Bz72H/wkXkk4AJrdphWE4jlqAd4EPbH I2E07VUNX1ii8raeV4+zt5kqbhnAUldgX6lALNNcEKmVTm/IWPeOZQ+4wsZ37TOvn2 9C2pHjlTVsunA== Date: Tue, 28 Oct 2025 07:32:54 -1000 From: Tejun Heo To: Roman Gushchin Cc: Andrew Morton , linux-kernel@vger.kernel.org, Alexei Starovoitov , Suren Baghdasaryan , Michal Hocko , Shakeel Butt , Johannes Weiner , Andrii Nakryiko , JP Kobryn , linux-mm@kvack.org, cgroups@vger.kernel.org, bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Kumar Kartikeya Dwivedi Subject: Re: [PATCH v2 15/23] mm: introduce bpf_task_is_oom_victim() kfunc Message-ID: References: <20251027232206.473085-1-roman.gushchin@linux.dev> <20251027232206.473085-5-roman.gushchin@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251027232206.473085-5-roman.gushchin@linux.dev> X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 4BDE1C0004 X-Stat-Signature: jc6kum5q3yf836oxr47x3jn8u1dgxduq X-Rspam-User: X-HE-Tag: 1761672776-592318 X-HE-Meta: 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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, Oct 27, 2025 at 04:21:58PM -0700, 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 > --- > mm/oom_kill.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 72a346261c79..90bb86dee3cf 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -1397,11 +1397,25 @@ __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); > +} In general, I'm not sure it's a good idea to add kfuncs for things which are trivially accessible. Why can't things like this be provided as BPF helpers? Thanks. -- tejun