From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 076DF51357C; Wed, 16 Sep 2026 15:22:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789572163; cv=none; b=sc/vGphRwUu1JlYRORmDNpBdNC8B5wdc3Ix2Y7+Edqu4xFFUq88ieJ6oiiX4M/CUesYbzVWNQJccVRqy2uuEDZFeCd4HAqYINrWo2O3soIY8hpdeup2BYwks7js1k5ZjVVurblpi40oSaA2ifdwnJDhSRZeXL5D+WXgvZ5ll5c8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789572163; c=relaxed/simple; bh=MdSYXNcj5cpRxN9+K4F4LkrmAThRRmL35UayAoBa7fs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=TZR6BDs3gBdwyl/uUmlc3+J/1qN0XNNIPiGQf5kly2DnDDMteksA88oChToyu1ifF826XZFJyeeGlHXdXgsVjjMpSIEjF8FLq1ViI08y+R+wjDnD/Dveb7CSe0e3FHMVTsOjd6TB+L4NukBdPym46LCiEWabYbqZXeg0YNonNCc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VTzvFepa; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VTzvFepa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D9981F000FF; Wed, 16 Sep 2026 15:22:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789572159; bh=AuNmQA5s10qS4VTTL4v5s8UJsbG/ZONw29ACJG8o3kA=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=VTzvFepapuMdEsmQOK1nJWTfIC9oryTuBzH3wAtW5cW7djRLKD9vRibINmbgqLfV0 Dd1+5D9STEb8HHfB0Kxw4xWx7JfkKyTpPJqU3O8NSDVebC801uRdbYWPcy4SpJLrFQ gdzhpfcn/gcXWbX3Rrz2NiFnZu7LNEadUzvImie2OQbbZTu684/X0ysV0nacmcm0cr FPEo/2C+DtYpM0uQPgqbJpP4KFQUvFpyxTx/KlGlBDJj0+1mhh/ZlvSsjMoq7mDIox TK68BiyrEe2bBcNUlfumABJfDnLuS1yzZZOweN4HPgPz8+pohI7VWRu6j6yD4Zj7O2 9m6HQaaXKT4Rw== Message-ID: <8bdc32dd-9d0a-40c7-908f-6f3a18b46a7b@kernel.org> Date: Wed, 16 Sep 2026 17:22:32 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next v11 1/2] mm/bpf: Add bpf_proactive_reclaim kfunc To: Kumar Kartikeya Dwivedi , Shakeel Butt , Hui Zhu 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 , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Hui Zhu References: From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/16/26 17:12, Kumar Kartikeya Dwivedi wrote: > 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 more to > address some of the selftest concerns. > > After that, any objections to taking this through bpf-next? Fine with me, I don't expect any conflicts in mm/internal.h. -- Cheers, David