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 3D9992C3757; Thu, 11 Jun 2026 12:16:05 +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=1781180167; cv=none; b=AbQmkcR0lU42X6bTUBvCq6hhuzade3YICvHeq8+c3Y+euHdEh8SMh4Vf+XBKGr7+jQbpySC+3ZAfHpW8LxlBcdu7K076hp0WAfcvEonMxkrR2sd/4Apym6owsjQ8PoY79YpRZ2TU8dVfVfIKOvBEgmQtX5+7hnvrEKJchg0lA8c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781180167; c=relaxed/simple; bh=zlj3YkxcT4JL+4VXrSfCWKR7kiY48sRG6NdujY/94Qk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=p06ZLY/ZhX/x5DxZLjuSYA2AO+iZuPV0QglhSqU1uWU58xu6rYECFcWftvTstP+X9rZdUXsqCAkYl+1F5dQwP5hz62NG7+FVwskoWuwin+hHzJLQxAdycbf77ooubAP0dp9RXkZznv9/Wsm+5YgHpkK1uaQL+I4xoDskwwqduOY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P+DY3/BC; 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="P+DY3/BC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 313911F00893; Thu, 11 Jun 2026 12:16:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781180165; bh=zlj3YkxcT4JL+4VXrSfCWKR7kiY48sRG6NdujY/94Qk=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=P+DY3/BCEBZzRZtbE52GFIAtKo1zeDJvzp4GMY0SymOe6AJgpPQdfX5ktQepYtqgQ 07DhZVeFK3U0nNwY3kswiPXQ9KMRRiILoiweLuIltMRr3GgupHTG2MBlwHjuo4dyeA uBI0De6byfQAVexGT4k206x4knGJ0YKPxRC5tFPO3TD3FZLwq/7hXRTQhfIF2PpwZX RrxBv5x2xTEMP74xsFCjCeq2A67rGbhY6QGfjHT2iBGPres6PNrUbCme2WhDGqe1zZ oVDvddpK+3yxpRcktB3tfmnPecjszPDWgBERs1WrIzmgMKruHciUeJm839zQ4kqouj 1jVs0Dh6475zg== Date: Thu, 11 Jun 2026 13:15:58 +0100 From: Lorenzo Stoakes To: Baolin Wang Cc: akpm@linux-foundation.org, david@kernel.org, hughd@google.com, willy@infradead.org, ziy@nvidia.com, liam@infradead.org, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2 00/11] add shmem mTHP collapse support Message-ID: References: <47f472ac-0b07-4ffa-a3d4-04fba621252f@linux.alibaba.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <47f472ac-0b07-4ffa-a3d4-04fba621252f@linux.alibaba.com> On Thu, Jun 11, 2026 at 07:46:55PM +0800, Baolin Wang wrote: > Hi Lorenzo, > > On 6/11/26 2:18 PM, Lorenzo Stoakes wrote: > > On Wed, Jun 10, 2026 at 06:29:08PM +0800, Baolin Wang wrote: > > > (Note: this patchset is not targeting v7.2, but posted for early feedback.) > > > > Hi Baolin, > > > > Speaking broadly, and to repeat what I said to Nico - I'd like to > > re-emphasise my _strong_ desire for us to pay down technical debt in THP > > code before adding any further major features. > > > > Really I'd have liked to see us do this _before_ khugepaged mTHP, but I > > didn't want to put Nico through more than he already endured with that > > series :) > > > > So I'd really like to see some action on that before we embark on any > > further significant changes. > > > > This is no comment on your changes, just something that we really need to > > address in THP generally. > > > > Will try to give some detailed commentary on the actual changes when I have > > time also :) > > I fully understand the current state of THP maintenance, which is why this > is an RFC. I’m not expecting it to be merged into mainline quickly (but > thanks to Lance for the comments). Ack, well maybe you'd be surprised if I didn't mention it ;) And I will try to have a look through on basis of the technical changes! > > Also, as Nico noted, it might be worth reviewing the mTHP collapse selftests > in this series firstly? as they can help validate the anonymous mTHP > collapse path for future changes. Yeah that sounds like a plan and thank you for writing them :) more testing is welcome and very much appreciated. Cheers, Lorenzo