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From:   Chuyi Zhou <zhouchuyi@bytedance.com>
To:     hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev,
        ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
        muchun.song@linux.dev
Cc:     bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        wuyun.abel@bytedance.com, robin.lu@bytedance.com,
        Chuyi Zhou <zhouchuyi@bytedance.com>
Subject: [RFC PATCH 0/2] mm: Select victim using bpf_select_task
Date:   Fri,  4 Aug 2023 17:38:02 +0800
Message-Id: <20230804093804.47039-1-zhouchuyi@bytedance.com>
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This patchset adds a new interface and use it to select victim when OOM
is invoked. The mainly motivation is the need to customizable OOM victim
selection functionality.

The new interface is a bpf hook plugged in oom_evaluate_task. It takes oc
and current task as parameters and return a result indicating which one is
selected by the attached bpf program.

There are several conserns when designing this interface suggested by
Michal:

1. Hooking into oom_evaluate_task can keep the consistency of global and
memcg OOM interface. Besides, it seems the least disruptive to the existing
oom killer implementation.

2. Userspace can handle a lot on its own and provide the input to the BPF
program to make a decision. Since the oom scope iteration will be
implemented already in the kernel so all the BPF program has to do is to
rank processes or memcgs.

Previous discussion link:
[1]https://lore.kernel.org/lkml/20230727073632.44983-1-zhouchuyi@bytedance.com/

Chuyi Zhou (2):
  mm, oom: Introduce bpf_select_task
  bpf: Add OOM policy test

 mm/oom_kill.c                                 |  57 ++++++-
 .../bpf/prog_tests/test_oom_policy.c          | 140 ++++++++++++++++++
 .../testing/selftests/bpf/progs/oom_policy.c  |  77 ++++++++++
 3 files changed, 267 insertions(+), 7 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/test_oom_policy.c
 create mode 100644 tools/testing/selftests/bpf/progs/oom_policy.c

-- 
2.20.1