From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (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 021B3199931; Tue, 9 Sep 2025 22:39:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757457580; cv=none; b=KxxeKZDGl8wf1boDYKqoaQJ4fLpBBbIrKvrLTkibvo53YMT33H8l8ufjxEaSS7yRj6EujuMsMMSI+gGPKzEHaF4REtmezwVPD4+T2Y/0DotHKNqBylmt7LpJxGKdKViw3g5MzG92M1baHqtoumiHWviK6jcls/jYSqZa1tc5LSE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757457580; c=relaxed/simple; bh=dC8rz4BxW9SQ2JeI/WxcV0VECaDximE95TZAzqBomJM=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=kchkUIgNK1Me/vSFF8i5Vbko26Dw9dsQR848pAF16upeskuKR1LwmqCAqrJdSZ1UAm8hKxfcCl5b/fzliXFsnYRNAtfpOZ/g6DR/3u6XINfZFlJZpX5VtSHA2T8ImBYazOhdjF39/5lPfTjZossoogGhYhXvTAwbn8jxDoGI6U4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=TvOUc/rv; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="TvOUc/rv" Received: from ehlo.thunderbird.net (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 589Md5a71810392 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 9 Sep 2025 15:39:05 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 589Md5a71810392 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025082201; t=1757457547; bh=o4pJzl4BWqncjRLwqdCVSmCaOJCq8m9Ifms3vJmzKBM=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=TvOUc/rvPHuoAgZik4kP6Jrk/1+TPY9+I66slCEYRMAAVaJliSrzt+2sOFL7uxfep TkUyZI254fJRZ0lrODF9atINh0A8S4jLrAmCkJHU6JXLFZKZC0KSUVdi0tmre9KWKN XbKdciAhvqcaNOwc7fFmyUBOA5BxnpqIS4Eb0rGthQiBgS5HHj+CzVzQJOWVF0iflT tgpvUETHe9/40V2F6BCYuDmvwT7GfqNk48CbFXskPApkAJTXDi/C8HYPbnObeJPLQM 4VGzdB3lbm4UCWwMufH5gTZgR2KMO3DzwNg9CgZkrpc9Dml+J/eRl9RSkkGtbvpN2l PQy3pTIde+vBg== Date: Tue, 09 Sep 2025 15:39:05 -0700 From: "H. Peter Anvin" To: Linus Torvalds CC: Arnd Bergmann , ksummit@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, imx@lists.linux.dev, Christophe Leroy , Richard Weinberger , Lucas Stach , Linus Walleij , Geert Uytterhoeven , Ankur Arora , David Hildenbrand , Mike Rapoport , Lorenzo Stoakes , Matthew Wilcox , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Ira Weiny , Nishanth Menon , =?ISO-8859-1?Q?Heiko_St=FCbner?= , Alexander Sverdlin , "Chester A. Unal" , Sergio Paracuellos , Andreas Larsson Subject: Re: [TECH TOPIC] Reaching consensus on CONFIG_HIGHMEM phaseout User-Agent: K-9 Mail for Android In-Reply-To: References: <4ff89b72-03ff-4447-9d21-dd6a5fe1550f@app.fastmail.com> Message-ID: Precedence: bulk X-Mailing-List: ksummit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On September 9, 2025 3:24:29 PM PDT, Linus Torvalds wrote: >On Tue, 9 Sept 2025 at 14:39, H=2E Peter Anvin wrote: >> >> 1 GB systems used highmem too, sadly=2E And 1 GB was the norm for a big= chuck of the late 32-bit era=2E > >Well, while on x86 1GB systems did use highmem, they'd typically not >use very much of it=2E > >IOW, they'd have about 900MB as lowmem (ok, I think it was 896MB to be >exact), with something like 120MB highmem=2E > >So they'd either lose a bit of memory, or they'd use the 2G:2G split=2E > >Or - and I think this is the main point - they'd stay on old kernels >like the ancient museum pieces they are=2E > >I'm not convinced it makes sense to have a modern kernel on a museum piec= e=2E > > Linus > Certainly=2E And the 2:2 split is probably the right thing for the old mac= hines anyway=2E