From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752512AbdBMLEl (ORCPT ); Mon, 13 Feb 2017 06:04:41 -0500 Received: from andre.telenet-ops.be ([195.130.132.53]:48040 "EHLO andre.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751949AbdBMLEi (ORCPT ); Mon, 13 Feb 2017 06:04:38 -0500 From: Geert Uytterhoeven To: Marek Szyprowski , Catalin Marinas , Will Deacon , Arnd Bergmann , Robin Murphy Cc: Magnus Damm , linux-arm-kernel@lists.infradead.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH/RESEND] arm64: defconfig: Enlarge CMA alignment to 2 MiB Date: Mon, 13 Feb 2017 12:04:18 +0100 Message-Id: <1486983858-11362-1-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some IOMMUs (e.g. Renesas IPMMU/VMSA) support only page sizes of 4 KiB, 2 MiB, and 1 GiB. With the default setting of CONFIG_CMA_ALIGNMENT = 8, allocations larger than 1 MiB are aligned to a 1 MiB boundary only. Hence a 2 MiB allocation may not be aligned, leading to a mapping of 512 4 KiB pages. Increase CONFIG_CMA_ALIGNMENT to allow mapping a 2 MiB buffer using a single PTE, decreasing memory usage and TLB pressure. Signed-off-by: Geert Uytterhoeven --- Is this useful? Should there instead be different defaults in Kconfig, depending on enabled platform support? --- arch/arm64/configs/defconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig index 7735cfba01c8e650..7af449f3f41435bc 100644 --- a/arch/arm64/configs/defconfig +++ b/arch/arm64/configs/defconfig @@ -144,6 +144,7 @@ CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug" CONFIG_DEVTMPFS=y CONFIG_DEVTMPFS_MOUNT=y CONFIG_DMA_CMA=y +CONFIG_CMA_ALIGNMENT=9 CONFIG_MTD=y CONFIG_MTD_BLOCK=y CONFIG_MTD_M25P80=y -- 1.9.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: geert+renesas@glider.be (Geert Uytterhoeven) Date: Mon, 13 Feb 2017 12:04:18 +0100 Subject: [PATCH/RESEND] arm64: defconfig: Enlarge CMA alignment to 2 MiB Message-ID: <1486983858-11362-1-git-send-email-geert+renesas@glider.be> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Some IOMMUs (e.g. Renesas IPMMU/VMSA) support only page sizes of 4 KiB, 2 MiB, and 1 GiB. With the default setting of CONFIG_CMA_ALIGNMENT = 8, allocations larger than 1 MiB are aligned to a 1 MiB boundary only. Hence a 2 MiB allocation may not be aligned, leading to a mapping of 512 4 KiB pages. Increase CONFIG_CMA_ALIGNMENT to allow mapping a 2 MiB buffer using a single PTE, decreasing memory usage and TLB pressure. Signed-off-by: Geert Uytterhoeven --- Is this useful? Should there instead be different defaults in Kconfig, depending on enabled platform support? --- arch/arm64/configs/defconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig index 7735cfba01c8e650..7af449f3f41435bc 100644 --- a/arch/arm64/configs/defconfig +++ b/arch/arm64/configs/defconfig @@ -144,6 +144,7 @@ CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug" CONFIG_DEVTMPFS=y CONFIG_DEVTMPFS_MOUNT=y CONFIG_DMA_CMA=y +CONFIG_CMA_ALIGNMENT=9 CONFIG_MTD=y CONFIG_MTD_BLOCK=y CONFIG_MTD_M25P80=y -- 1.9.1