From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 443D0E909A6 for ; Tue, 17 Feb 2026 14:21:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=MLpdqnB7xLYFqBu+I91ADfRDGElANrP7WKshi9XrU0A=; b=JHOtOnEwwj6oOyOPDI5d6mM3qv uRM2fJs80XkYQrRl4+HA5XTk4vkiifIyNqhqdVjf7Y7eZlsAac0pJ9kzwPaTAQIEb9lxLnLa8DUPT re5LYcoG1EUYXxZfi+fjNWIXRg7nxSg+A7JkxwoMHrTEd6ge9b461TKhJwDUbCZNkMgMwjGHJhqv7 3csnvPlHO3qoAv5sm5zU9ijGkbC8U2HK2JSS5SwfVcKGVC6YNRAVJeQ0aUwRFX+2P5jOVd9kfhtG7 bUj949ipHt11y4az6wT30I52MoOrN1rw/L0hTZc2wbNvtSKnwntMQ1nlfLnCAI0uGqzrOUISTZBrF pyMYwQFA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vsLxK-00000008Q6o-1puA; Tue, 17 Feb 2026 14:21:38 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vsLxH-00000008Q5V-2OKG for linux-arm-kernel@lists.infradead.org; Tue, 17 Feb 2026 14:21:37 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 523541477; Tue, 17 Feb 2026 06:21:27 -0800 (PST) Received: from [10.1.30.186] (XHFQ2J9959.cambridge.arm.com [10.1.30.186]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EEFCD3F62B; Tue, 17 Feb 2026 06:21:31 -0800 (PST) Message-ID: <7f30a8e4-49c3-421d-be05-08afb544aa41@arm.com> Date: Tue, 17 Feb 2026 14:21:30 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 6.6 0/3] arm64: Speed up boot with faster linear map creation Content-Language: en-GB To: Greg KH Cc: stable@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Jack Aboutboul , Sharath George John , Noah Meyerhans , Jim Perrin References: <20260217133411.2881311-1-ryan.roberts@arm.com> <2026021700-chafe-jurist-cb24@gregkh> <17c9efaf-6c33-4485-bde2-345cc15ac000@arm.com> <2026021718-citrus-parakeet-dc60@gregkh> From: Ryan Roberts In-Reply-To: <2026021718-citrus-parakeet-dc60@gregkh> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260217_062135_653511_9E2D9D5B X-CRM114-Status: GOOD ( 16.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 17/02/2026 14:10, Greg KH wrote: > On Tue, Feb 17, 2026 at 01:58:36PM +0000, Ryan Roberts wrote: >> On 17/02/2026 13:50, Greg KH wrote: >>> On Tue, Feb 17, 2026 at 01:34:05PM +0000, Ryan Roberts wrote: >>>> Hi All, >>>> >>>> This series is a backport that applies to stable kernel 6.6 (base v6.6.126), for >>>> some speed ups to enable significantly faster booting on systems with a lot of >>>> memory. The patches were originally posted at: >>>> >>>> https://lore.kernel.org/linux-arm-kernel/20240412131908.433043-1-ryan.roberts@arm.com/ >>>> >>>> ... and were originally merged upstream in v6.10-rc1. >>>> >>>> I'm requesting this be merged to stable on behalf of a partner who wants to get >>>> the benefit of this series in Debian 12. >>> >>> Why can't they just use a newer kernel version (i.e. 6.12)? Surely they >>> would be able to justify moving to a newer kernel for performance >>> reasons, why enable them to stay on an older one, just delaying the >>> inevitable upgrade they will have to do anyway in a year or so? >> >> I can't answer this presicely, but I did ask and push for that approach. As I >> understand it, they are stuck with Debian 12, which is stuck with kernel 6.1. >> The Debian maintainer apparently requested that these go through stable in order >> to get them into Debian 12. > > I understand the position of Debian not wanting to take patches for new > features that are not already upstream, but really, Debian offers a > newer kernel for hardware that wants to use it for things like this, > right? Why not just use that instead? Let me go push a bit harder. But I expect we are in the grey zone between bug and feature here; this is a performance bug fix, not a new feature. By selectively backporting I'm guessing they are avoiding the risk of new features that a new kernel brings introducing new bugs? I'm guessing there is a higher qualification bar for that. > > thanks, > > greg k-h