Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756158AbaDLD3R (ORCPT ); Fri, 11 Apr 2014 23:29:17 -0400 Received: from mail-qc0-f179.google.com ([209.85.216.179]:46024 "EHLO mail-qc0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755706AbaDLD3P (ORCPT ); Fri, 11 Apr 2014 23:29:15 -0400 Date: Fri, 11 Apr 2014 23:29:11 -0400 (EDT) From: Nicolas Pitre To: Liu Hua cc: linux@arm.linux.org.uk, will.deacon@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, wangnan0@huawei.com, peifeiyue@huawei.com, liusdu@126.com, m.szyprowski@samsung.com Subject: Re: [PATCH v2 0/2] change ARM linux memory layout to support 32 CPUs In-Reply-To: <1397203252-22977-1-git-send-email-sdu.liu@huawei.com> Message-ID: References: <1397203252-22977-1-git-send-email-sdu.liu@huawei.com> User-Agent: Alpine 2.11 (LFD 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 11 Apr 2014, Liu Hua wrote: > Hi Nicolas or Russell, > > This patch series change fixmap mapping region to suppport 32 CPUs. > Because the "top_pmd" covers 0xfffe0000 - 0xffffffff(2M). And part > is used by vector table. So I move this region down to 0xffc00000 > - 0xffdffff. > > > I have tested the patches on arma9(2 CPUs) and arma15(16 CPUs) platforms > > BTW, As we know we can configure NR_CPUS up to 32. So we need 2048K > at most. But for ARM systems with less cpus, there is a waste > of virtual address. So should we change its size according to > NR_CPUS, as what MIPS linux does ? It is probably not worth the bother. We lived with this area reserved for static DMA mapping while there was no longer any DMA mapped there for quite a while. > > Changes from v1: > --------------- > - changed documentation for ARM linux memory layout. > - moved fixmap mapping region, not just extended. > > Liu Hua (2): > ARM : DMA : remove useless information about DMA > ARM : extend fixmap mapping region to support 32 CPUs > > Documentation/arm/memory.txt | 8 ++------ > arch/arm/include/asm/fixmap.h | 4 ++-- > arch/arm/include/asm/highmem.h | 1 + > arch/arm/include/asm/memory.h | 2 -- > arch/arm/mm/highmem.c | 10 +++++----- > arch/arm/mm/mm.h | 7 +++++++ > arch/arm/mm/mmu.c | 4 ++++ > mm/highmem.c | 1 + > 8 files changed, 22 insertions(+), 15 deletions(-) > > -- > 1.9.0 > -- 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/