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[192.26.29.3]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4870bf27a41sm7320342f8f.18.2026.09.16.08.12.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 16 Sep 2026 08:12:53 -0700 (PDT) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 16 Sep 2026 17:12:52 +0200 Message-Id: Cc: "Roman Gushchin" , "JP Kobryn" , "Andrew Morton" , "Andrii Nakryiko" , "Eduard Zingerman" , "Ihor Solodrai" , "Alexei Starovoitov" , "Daniel Borkmann" , "Martin KaFai Lau" , "Song Liu" , "Yonghong Song" , "Jiri Olsa" , "Emil Tsalapatis" , "Shuah Khan" , "Barry Song" , "Geliang Tang" , , , , , "Hui Zhu" , "David Hildenbrand (Arm)" Subject: Re: [PATCH bpf-next v11 1/2] mm/bpf: Add bpf_proactive_reclaim kfunc From: "Kumar Kartikeya Dwivedi" To: "Shakeel Butt" , "Hui Zhu" X-Mailer: aerc 0.21.0 References: In-Reply-To: On Tue Sep 15, 2026 at 7:26 PM CEST, Shakeel Butt wrote: > On Tue, Sep 15, 2026 at 08:29:35PM +0800, Hui Zhu wrote: >> From: Hui Zhu >> >> BPF programs can observe memory pressure on a cgroup, e.g. refault >> stats via bpf_mem_cgroup_page_state(), but cannot act on it: >> triggering reclaim requires writing to memory.reclaim, which BPF >> cannot do. >> >> Add bpf_proactive_reclaim(), a sleepable kfunc performing one >> proactive reclaim pass on a memcg, like a write to memory.reclaim >> but without retrying until the target is reached, so that when and >> how hard to reclaim is BPF policy rather than hard-coded thresholds. >> The reclaim target of a single call is capped at MEMCG_CHARGE_BATCH, >> as high_work_func() does for memory.high; reclaiming more is left to >> the program, which can call the kfunc once per bpf_wq callback and >> stop at any point. It is limited to BPF_PROG_TYPE_SYSCALL, because >> other sleepable programs may run with filesystem locks held, on >> which the reclaim path could deadlock via filesystem shrinkers. >> >> Convert MIN_SWAPPINESS, MAX_SWAPPINESS and SWAPPINESS_ANON_ONLY from >> macros to an enum so that they are emitted into BTF and usable from >> BPF programs via vmlinux.h. >> >> Signed-off-by: Hui Zhu > > Acked-by: Shakeel Butt Hi Andrew and David, This looks good to me (from BPF side) and Shakeel, Hui might respin once mo= re to address some of the selftest concerns. After that, any objections to taking this through bpf-next? Thanks