From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-184.mta1.migadu.com [95.215.58.184]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 04DE6391842 for ; Thu, 27 Aug 2026 10:36:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.184 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787827022; cv=none; b=m7CHKHdBVtV0h/h8/0fnJQ7t6s6/+ILrUbb3xKOlAOUG5kuM4qRgQgveZufOfh9y8LYWKzt9dhdKPJ9frUTDDFFD/rcbxxTHalVw//blTbV7F3eMST+mCR/TIu/6vr49gA1EcTsKaKBPPash+N8g78mba77hofptg9hqfaUm+s4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787827022; c=relaxed/simple; bh=eBC1hmrN/najiAXcokA+qH1/b3vDj9vs9vwMDANb+no=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=YXsfr/U8jMhx/g8JiPmI9xfSf4GUUTSkrUOT1HVi/4K5yciYZN8tA83pU3Crm6WGYJLQubXyQRH7zL/joz8skntVdnxohSv1rQj4q/R4SWyVhKAaL6yvlGZytFGHaOMkw/VLbjS9iItws7UTTWTm9oDGSdiA2/m1sifeBV8Ksj0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Yhx70kXZ; arc=none smtp.client-ip=95.215.58.184 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Yhx70kXZ" X-Envelope-To: linux-kselftest@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=eBC1hmrN/najiAXcokA+qH1/b3vDj9vs9vwMDANb+no=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787827017; v=1; x=1788431817; b=Yhx70kXZKYKAQ5vO0KaAwPPEUUGrf3DtASy7UyRuwX50dLrkafn0tHR0sSOeBm7O2KsvfY3p vV6mjy61F+drdbWMfNOxln7QZp6hhFRY4t56gPcc+moB31HVJMNql0NQQfyGha0NMD9LJWS6nJA ggcEpT2iWzXgmnl6jTTQISJw= X-Envelope-To: linux-kselftest@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 1d9f78061294dc88; Thu, 27 Aug 2026 10:36:57 +0000 X-Mizu-Trace-ID: 1d9f78061294dc88 X-Migadu-Flow: FLOW_OUT From: "Hui Zhu" To: Roman Gushchin , JP Kobryn , Shakeel Butt , Andrew Morton , Andrii Nakryiko , Eduard Zingerman , Ihor Solodrai , Alexei Starovoitov , Daniel Borkmann , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Shuah Khan , Barry Song , Geliang Tang , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Cc: Hui Zhu Subject: [PATCH bpf-next v5 0/2] bpf: BPF-driven proactive memcg reclaim Date: Thu, 27 Aug 2026 18:36:28 +0800 Message-ID: X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 on a chosen cgroup requires writing to memory.reclaim, which BPF cannot do. This series adds bpf_proactive_reclaim(), a sleepable kfunc performing one proactive reclaim pass on a target memcg, so when and how hard to reclaim is BPF policy rather than hard-coded thresholds. The use case we are looking at is protecting high-priority workloads: a BPF program monitors the state of a high-priority cgroup and, when it degrades (e.g. PSI rises or refaults increase, as in the selftest), asynchronously reclaims memory from low-priority cgroups via bpf_wq and bpf_proactive_reclaim(), giving the pressured cgroup more free pages. Another use case: several vendor-maintained kernels carry private implementations that trigger asynchronous reclaim when a memcg enters a certain state. These exist for historical and partly psychological reasons, but the underlying demand is real. We expect BPF-driven proactive reclaim, combined with the BPF hooks for the memory controller currently under discussion and development, to serve these needs in mainline, reducing kernel fragmentation and improving kernel maintainability. Hui Zhu (2): mm/bpf: Add bpf_proactive_reclaim kfunc selftests/bpf: Add memcg async reclaim test mm/bpf_memcontrol.c | 46 ++ .../bpf/prog_tests/memcg_async_reclaim.c | 480 ++++++++++++++++++ .../selftests/bpf/progs/memcg_async_reclaim.c | 181 +++++++ 3 files changed, 707 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/memcg_async_reclaim.c create mode 100644 tools/testing/selftests/bpf/progs/memcg_async_reclaim.c -- 2.53.0