linux-kernel - [PATCH v1 08/14] mm: introduce bpf_task_is_oom

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Message-ID: <20250818170136.209169-9-roman.gushchin@linux.dev>
Date: Mon, 18 Aug 2025 10:01:30 -0700
From: Roman Gushchin <roman.gushchin@...ux.dev>
To: linux-mm@...ck.org,
	bpf@...r.kernel.org
Cc: Suren Baghdasaryan <surenb@...gle.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Michal Hocko <mhocko@...e.com>,
	David Rientjes <rientjes@...gle.com>,
	Matt Bobrowski <mattbobrowski@...gle.com>,
	Song Liu <song@...nel.org>,
	Kumar Kartikeya Dwivedi <memxor@...il.com>,
	Alexei Starovoitov <ast@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	Roman Gushchin <roman.gushchin@...ux.dev>
Subject: [PATCH v1 08/14] mm: introduce bpf_task_is_oom_victim() kfunc

Export tsk_is_oom_victim() helper as a bpf kfunc.
It's very useful to avoid redundant oom kills.

Signed-off-by: Roman Gushchin <roman.gushchin@...ux.dev>
---
 mm/oom_kill.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 67afcd43a5f7..fe6e69dfbdba 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -1388,11 +1388,25 @@ __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);
+}
+
 __bpf_kfunc_end_defs();
 
 BTF_KFUNCS_START(bpf_oom_kfuncs)
 BTF_ID_FLAGS(func, bpf_oom_kill_process, KF_SLEEPABLE | KF_TRUSTED_ARGS)
 BTF_ID_FLAGS(func, bpf_out_of_memory, KF_SLEEPABLE | KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_task_is_oom_victim, KF_TRUSTED_ARGS)
 BTF_KFUNCS_END(bpf_oom_kfuncs)
 
 static const struct btf_kfunc_id_set bpf_oom_kfunc_set = {
-- 
2.50.1