From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-189.mta0.migadu.com (out-189.mta0.migadu.com [91.218.175.189]) (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 6F3C72EA154 for ; Tue, 7 Jul 2026 08:10:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.189 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783411827; cv=none; b=X1aW8QAPNaNQlRlbDQfS1xfIKKsLMjUioGz8iTKAPKKSREYq+Pnpqi6hfgfBZhSIIRIw44qBjjbcOr5AlStZF5QwyXRfRbyOtsKZgYczSF1JOAQmpuQDwLpgtYQ4CxsY7UbJkGytMaYgjEy/1U5EDVkCrY7V0GO0gqRt2LAWGes= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783411827; c=relaxed/simple; bh=JoijE4uJCyq2j4khlPNuxF9JMy8fYGszG7NSw2HhBR4=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Message-Id:References:To; b=pfgWJxU2Jnc6HEgb3OsaCpS8cXoWiB3y4rZOydVievKecvolmapQB+rpB7ASsyVWCasxatDCXmZV2PQG5yZq7+rqaOZ1OBKLf/ndVI3sMGt6F0BEzYHGJ6YS+ptVHydCOWvDNSDnhTfNUq5+XzmKPzuzgjY0Ni05D00bW43lyoY= 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=Mr2sA5O2; arc=none smtp.client-ip=91.218.175.189 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="Mr2sA5O2" Content-Type: text/plain; charset=us-ascii DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1783411814; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JoijE4uJCyq2j4khlPNuxF9JMy8fYGszG7NSw2HhBR4=; b=Mr2sA5O2fwOZH+tdJVJbtFshcbUt3g6menEXK/k6fjP66J6bIxXN/uaF0WmGzyaLj2b2VW cY7kl73i6uSScBXlAmniWx4i6iDgVdgQJxt9MsQIpFlyQva0MSuZ1QtqGe3FGadARI53GI anr7Vxi7SJDpzawCZrnJt5t0V6M76zg= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3864.600.51.1.1\)) Subject: Re: [RFC PATCH 0/6] mm/hugetlb: Dynamic, NUMA-aware HugePage Cache & Free Page Reporting X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Muchun Song In-Reply-To: <9624988a-366e-4884-9408-3f3b88c27290@kernel.org> Date: Tue, 7 Jul 2026 16:09:35 +0800 Cc: Sourav Panda , 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, mst@redhat.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 Content-Transfer-Encoding: quoted-printable Message-Id: <48E0B0E2-4CE2-40B5-A7C3-9DEEF9F49C41@linux.dev> References: <20260707064235.1386552-1-souravpanda@google.com> <9624988a-366e-4884-9408-3f3b88c27290@kernel.org> To: "David Hildenbrand (Arm)" X-Migadu-Flow: FLOW_OUT > On Jul 7, 2026, at 15:29, David Hildenbrand (Arm) = wrote: >=20 > 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. >=20 > Hi, >=20 > 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. >=20 > We want to have less special casing and less special sauce, not more. >=20 > Now, there is nothing wrong in making hugetlb be less special, by = making it use > more of core infrastructure etc. +1 HugeTLB is already complex today, and the last thing we want is to = compound this complexity by piling more features on top of it. I fully share your = view that we should avoid going down this direction. Thanks, Muchun >=20 > 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? >=20 > --=20 > Cheers, >=20 > David