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[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 cc: linux-arm-kernel@lists.infradead.org, Yongtaek Lee , Russell King , linux-kernel@vger.kernel.org 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 Sender: linux-kernel-owner@vger.kernel.org Precedence: list List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: nicolas.pitre@linaro.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.215.47 as permitted sender) smtp.mailfrom=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , 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 --- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ 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