From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-129.mta0.migadu.com [91.218.175.129]) (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 890593DD523 for ; Fri, 25 Sep 2026 05:44:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.129 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790315068; cv=none; b=KudJaAFearTvH0el8UyFG7vH9ZrjiyVz/5PHOnJ/1NKwHxC6sqJWItTLQ8SdBiF/3sJ24aprMG5dqDNrg+rZEc7gASNgveyKyHo98MZ7l12MMzdGNlmprK+YW4e70IJqFrqhegJKqmcg/WOAPWX7y/JigLUOMFud2cQc8UFh9h4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790315068; c=relaxed/simple; bh=5F6F7qba1uzyjFZMv+EeaWChEVyxbKI9bB3fX112gzw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=Wf99/q/VWGoukd5W5oOWtamNZ/IrOAy/k2IsMH66LNuhY9nfslh9ajfUMOyiEOig2u1tnlOEAc3caf+L2fWUq9g6cgINXjpi0s95D7PVQXKhtCsviXUJDAaQOzbJMG+h6oW9Rc1HxRWPwNmJyGTla1BnZBOi7bA+Nf9g9iBkj3Q= 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=o1wGczzr; arc=none smtp.client-ip=91.218.175.129 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="o1wGczzr" X-Envelope-To: damon@lists.linux.dev DKIM-Signature: a=rsa-sha256; bh=5F6F7qba1uzyjFZMv+EeaWChEVyxbKI9bB3fX112gzw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790315063; v=1; x=1790919863; b=o1wGczzrshXxLV2QjROjX1EmaKEI+0NMLUy52U0HQRDzLQ1pMkq3GfvTcrNhQLweCSz3Vq0p mKs/NXaNpLLLX8qmPmIFndk87LGkzNsUM8ScNLgiC30XOBgqrRq9P71CcH6O+gKfnl8HlO00qov NsLoSHYcJb3mTj81aMk9vn+o= X-Envelope-To: damon@lists.linux.dev Received: by smtp.migadu.com with ESMTPS id 14310745666562df; Fri, 25 Sep 2026 05:44:13 +0000 X-Mizu-Trace-ID: 14310745666562df X-Migadu-Flow: FLOW_OUT From: Lance Yang To: sj@kernel.org, mst@redhat.com, david@kernel.org Cc: damon@lists.linux.dev, linux-mm@kvack.org, virtualization@lists.linux.dev, ryncsn@gmail.com, kunwu.chan@gmail.com, lianux.mm@gmail.com, baohua@kernel.org, xueyuan.chen21@gmail.com, Lance Yang Subject: [FYI] DAMON and virtio-balloon in DeepSeek's DSec paper Date: Fri, 25 Sep 2026 13:44:08 +0800 Message-ID: <20260925054408.10431-1-lance.yang@linux.dev> X-Mailer: git-send-email 2.49.0 Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi all, I was reading DeepSeek's new DSec paper[1] and found a nice use of DAMON and virtio-balloon: With this kind of workload, an agent may read a file once and never touch it again, while those pages remain in the guest page cache. Without memory pressure in the guest, they can stay cached even though the host would like that memory back ... The trick is DAMON + virtio-balloon free-page reporting :) DAMON reclaims cold file pages from the guest page cache; buddy gets a chance to coalesce them into reportable blocks, and virtio-balloon passes those blocks to Firecracker. Firecracker can then drop the host backing with MADV_DONTNEED. And it worked: time-integrated host memory use fell by 21.2%, while peak usage stayed about the same, with no significant CPU overhead. Pretty cool to see these pieces show up in another real, large-scale system :) Kernel work still changes the world. Cheers to that! Anyhow, I still don't know DAMON and virtio-balloon as well as I should (mostly I just know the people who built them) :P [1] https://arxiv.org/html/2609.22978 Cheers, Lance