From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 3A6BF3E51D2 for ; Tue, 7 Jul 2026 10:25:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783419948; cv=none; b=Eu36+EfLhhHDxX8Lr4jSydIuUYRPLd5FnWTydGqnQHGUbRSseQNaem2fO8AqmL3ht0cJqeNSNPxgnEJCxH9If1qrSESfgznS8bmNWQBPldj9Ur7XlLZgIUyBgvCl3SSGTulu6wQvUx36hYvyeIdvyG4YD+4o8u7QFOfkKhRoQAk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783419948; c=relaxed/simple; bh=gqOFLV/X0owYRcnHzvrsp/DH0uPVs/VkzGR4wK4JoEk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QbqOWnUCIvFVLnCC9tYLMP4K18ORUE0LBxEPT8cudfuheg74D+SWpt/QlHQ/19+8JRw/4/AYStYDcmN5HmHuafOI6Wjri4t7k0FSwnRJRJ2iBZmPlYlj0j+g8aIFg57KNCCaj0UFppbUpJm5OoaOiO9v+nADjZYdkegfY+AQ8Hw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=UMqazu3Q; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=OZdLAA90; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UMqazu3Q"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="OZdLAA90" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783419943; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VR1L8Tfvs37DPjneOYKS8+jqtMz73BhJHMeN7x0oADU=; b=UMqazu3QrR8Yyd6QZ8fXhCk9DN/PZD6NYTTXO1EoLHWHBk5klGHolsl8okD4q9M7aVah7y fE/x7LoIvAhyVKL76md/6s3iUgJCrCgs1sLQc/U9nKFH/6PRC8ykihVtDNRzzgdRPi95p8 YxFGMQx7KwANzmSkwko9cZC6OTiC7mI= Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-17-pTQLfgkvPDmi5opsAPnUgg-1; Tue, 07 Jul 2026 06:25:42 -0400 X-MC-Unique: pTQLfgkvPDmi5opsAPnUgg-1 X-Mimecast-MFC-AGG-ID: pTQLfgkvPDmi5opsAPnUgg_1783419941 Received: by mail-wm1-f72.google.com with SMTP id 5b1f17b1804b1-493c20d0468so54496175e9.1 for ; Tue, 07 Jul 2026 03:25:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1783419941; x=1784024741; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=VR1L8Tfvs37DPjneOYKS8+jqtMz73BhJHMeN7x0oADU=; b=OZdLAA90hZClBd9ZaS4A7GjeCRQeL+VBh5NO0bYmK/mSaXddnnOcNQgZOZnyhN5hgt 6hUk1EniddSpJeDE9mN2CoPlOQGFwYyf8tWKHPLV5W7WghRV4qfqwPAc+jOgKSxSWLc8 kebgulCLg1ZrAgu4Q/MQJEVK7JEJsyFfOkCfu40zHfz2hrZ2vZO7pRydmuyy5E8OuIS5 kOyCRtCp2XpsD93hM6dwiMMZar0eXrX4ykHFhPryvH/CTLlyiDUnzjk7kv7JWEXOm63n DMjTu1gPno/GnO6PpZcdk5RhvM6w78LZUGvPFRmicJ+aQd5G5JHJLvBiXXFdaZduUJWD Z5lQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783419941; x=1784024741; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=VR1L8Tfvs37DPjneOYKS8+jqtMz73BhJHMeN7x0oADU=; b=DS3di8bEqTF9ylg5/BwT2a0XqKulpx0laRypIaKAcRc0HPTvcP5t+zHmMI7WXNTKD7 OT/QG4y96q2lMEyvIC0tVfKniggvUDKDSO2XzL9oTzQjASkKggXk7DvGTNHP5jBiwDln 9U4alxbZSicw2TCj3ZiGshkxU5QZFFzFesmCe006+BTM8rYeC8Q9Pkn/3ac36DCIK77F kcvhIr1ftSi0kl5J77XiB7Sd665lC+v/9EjGQrADwFOIuVa0HpeangDW+N+5M0U6FYPR WJqV6ft/IYFpSRRYI5LHY3ofY1z2uUdk9vgSmcaAnsctcwb3M2oxva5lRFHzLnoTAHMl A+bA== X-Forwarded-Encrypted: i=1; AHgh+RoIKWRf4dBoQrtmYvkEIp/yh5Tr64KNjzpOQOSmdGC8O3rsL0CrOqWAwV3rRkArGlkloKW4o7lyIAA=@vger.kernel.org X-Gm-Message-State: AOJu0YwREkqnbqOuVzEJwSHRXpzjNT0o2xBYS1emkxscpmzrVwjrK1nV +d0JzBH9wH/lbvT/KNwHlEbWfO5O4C3RsZcPZxaIsBPFpCbRQ5nnP84egt9OY19E5K8ECja7wTo kl6ficeB9CLnlYSbRgidlCmrroIMHkEO+32GjlYFC8Ui+orGB8QshMQn8yRRDVg== X-Gm-Gg: AfdE7cnFUXuHi3IWiNnB7cz6eEac5klvQHbW+5gzt/ippNY5tkbai/MXAYCZVbhvQlH fzosuf1DyvVZaIEtAoUGZOyhx17fVtwgyv33tOKpSb4E6Vkgjk72aaYBJHIOSNDEeDGfxQAAXN+ mTZeLikqIrNT48lu0tsyF2fF6oyNhlFHJU4nWY11VewieXIWOuOzbj11pHalyH7AH8CS4sTmnHs 9vXmyCV/atqHxiI3kmzpnWUg3pJAFZGvRM3aJaugY6P7myjIalCvbKw/Dxwcm2Fl69UDUaGjl6z cddiNYM5eN2JidmyR/Qlglgi1HnTj/tyMedqMocmqDry4Gka8+SFN5Bk1/s8AkpRVH6J+/pidpe n35kWObIzjh60UtWzE94sq8lZffpjHIsW X-Received: by 2002:a05:600c:1383:b0:493:b647:1acd with SMTP id 5b1f17b1804b1-493df090a95mr49448565e9.36.1783419941244; Tue, 07 Jul 2026 03:25:41 -0700 (PDT) X-Received: by 2002:a05:600c:1383:b0:493:b647:1acd with SMTP id 5b1f17b1804b1-493df090a95mr49448105e9.36.1783419940603; Tue, 07 Jul 2026 03:25:40 -0700 (PDT) Received: from redhat.com (IGLD-80-230-68-31.inter.net.il. [80.230.68.31]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47aa039b126sm32286020f8f.24.2026.07.07.03.25.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Jul 2026 03:25:40 -0700 (PDT) Date: Tue, 7 Jul 2026 06:25:36 -0400 From: "Michael S. Tsirkin" To: "David Hildenbrand (Arm)" Cc: Sourav Panda , muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, mhklinux@outlook.com, fvdl@google.com, gthelen@google.com, mike.kravetz@oracle.com, pasha.tatashin@soleen.com, rientjes@google.com, riel@surriel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [RFC PATCH 0/6] mm/hugetlb: Dynamic, NUMA-aware HugePage Cache & Free Page Reporting Message-ID: <20260707062428-mutt-send-email-mst@kernel.org> References: <20260707064235.1386552-1-souravpanda@google.com> <9624988a-366e-4884-9408-3f3b88c27290@kernel.org> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9624988a-366e-4884-9408-3f3b88c27290@kernel.org> On Tue, Jul 07, 2026 at 09:29:07AM +0200, David Hildenbrand (Arm) wrote: > On 7/7/26 08:42, Sourav Panda wrote: > > Overview > > This patch series introduces a dynamic, NUMA-aware HugePage Cache, > > backed by a kernel shrinker to safely return memory under pressure, and > > integrates it with Free Page Reporting (virtio-balloon) for HugeTLB, > > specifically targeting gigantic (1GB) hugepages. The goal is to solve > > the tradeoff between allocation latency and memory > > fungibility in virtualized and heterogeneous cloud environments. > > Hi, > > in general, we consider hugetlb nowadays to be mostly in feature freeze, as we > realized a while ago that adding more special casing on top of something too > special for all of MM is only going to hurt us more in the long run. > > We want to have less special casing and less special sauce, not more. > > Now, there is nothing wrong in making hugetlb be less special, by making it use > more of core infrastructure etc. > > But optimizing for surplus hugetlb pages by teaching hugetlb about new caches > and its custom free-page-reporting support rather looks like the wrong direction > for me? > > -- > Cheers, > > David It is currently bypassing free-page-reporting completely. Making existing free lists not ignore free-page-reporting would maybe considered "making it be less special"?