From patchwork Mon Sep 7 15:34:36 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Pitre X-Patchwork-Id: 7136621 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id A6B2CBEEC1 for ; Mon, 7 Sep 2015 15:38:24 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E1FAC2079C for ; Mon, 7 Sep 2015 15:38:23 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 19B2A20776 for ; Mon, 7 Sep 2015 15:38:23 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZYyRk-0004YP-Im; Mon, 07 Sep 2015 15:35:04 +0000 Received: from mail-qk0-f174.google.com ([209.85.220.174]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZYyRh-00043c-2X for linux-arm-kernel@lists.infradead.org; Mon, 07 Sep 2015 15:35:01 +0000 Received: by qkcj187 with SMTP id j187so33859593qkc.2 for ; Mon, 07 Sep 2015 08:34:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version:content-type; bh=JGrfovxl//k+7mbKjKvdQYo6uszeNWUSXAJ/3EfMLCo=; b=FjVgRWJ0mO/SSowUczt5u+wtKgpNsunO7tsbPwqtu7XTxWrjFIfB6iPUrP0Nq1ALSc L+zLeIXsKKFeZNvJH6zceX1t+flDXMS6nZSluLCn3eabhCzh4dGLATk+M231ogB3QYPa OhGPNSEPkgUcQgfmC6ZCGlUFjJt7eOnk9i+rv6JAnIAB5XV4kTYK/ynfjIcPxMjaWnj+ 1pZIwNNaArJZ3UBYaU9lkP8Exs8cdYhewUafa410ibKfn/EBw0PKwdwGbqJXMZENPXs4 FYwN8mLN6KoegHfvwxihO3khq2+2Ldlny7x2SsMCJLtznrXqGplrTnCbzAECsx3vaKj2 clZA== X-Gm-Message-State: ALoCoQk42edypAyA3uqRR5Ba6kea8pY1pewOWTVMKvrDgwjN7LjZTZC/Qi/AEw8NMsngplSDDs9W X-Received: by 10.55.209.135 with SMTP id o7mr27426255qkl.16.1441640079053; Mon, 07 Sep 2015 08:34:39 -0700 (PDT) Received: from xanadu.home (modemcable065.157-23-96.mc.videotron.ca. [96.23.157.65]) by smtp.gmail.com with ESMTPSA id z128sm53599qhd.43.2015.09.07.08.34.37 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Sep 2015 08:34:37 -0700 (PDT) Date: Mon, 7 Sep 2015 11:34:36 -0400 (EDT) From: Nicolas Pitre To: Arnd Bergmann Subject: Re: [PATCH] ARM: fix bug which lowmem size is limited to 760MB In-Reply-To: <1713935.2YV1sNJUyb@wuerfel> Message-ID: References: <20150903091044.GW21084@n2100.arm.linux.org.uk> <1441276233-14566-1-git-send-email-ytk.lee@samsung.com> <1713935.2YV1sNJUyb@wuerfel> User-Agent: Alpine 2.20 (LFD 67 2015-01-07) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150907_083501_312296_D5329E60 X-CRM114-Status: GOOD ( 16.54 ) X-Spam-Score: -2.6 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Russell King , Yongtaek Lee , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Mon, 7 Sep 2015, Arnd Bergmann wrote: > Given how much more common 1GB hardware configurations are compared to 768MB > configuration, we could however think about adding a VMSPLIT_3G_OPT option > that x86 has (also VMSPLIT_2_75G on ARCH_TILE), to allow using the entire > 1GB of lowmem without going all the way to VMSPLIT_2G. That option would > also let us use the entire 768MB on the machines that Yongtaek Lee is > interested in. That's easy enough: That shifts the risk to user space though. But if there is a regression there, it will manifest itself on all systems and not only with some particular hardware. Nicolas diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 0d1b717e1e..a63970f211 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1470,6 +1470,8 @@ choice config VMSPLIT_3G bool "3G/1G user/kernel split" + config VMSPLIT_3G_OPT + bool "3G/1G user/kernel split (for full 1G low memory)" config VMSPLIT_2G bool "2G/2G user/kernel split" config VMSPLIT_1G @@ -1481,6 +1483,7 @@ config PAGE_OFFSET default PHYS_OFFSET if !MMU default 0x40000000 if VMSPLIT_1G default 0x80000000 if VMSPLIT_2G + default 0xAF000000 if VMSPLIT_3G_OPT default 0xC0000000 config NR_CPUS