From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Fri, 6 Jul 2018 18:06:17 +0100 Subject: [PATCH v2] arm64: add ARM64-specific support for flatmem In-Reply-To: <20180706170215.56116-1-nkela@cisco.com> References: <20180706170215.56116-1-nkela@cisco.com> Message-ID: <20180706170617.GB4961@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Jul 06, 2018 at 10:02:15AM -0700, Nikunj Kela wrote: > Flatmem is useful in reducing kernel memory usage. > One usecase is in kdump kernel. We are able to save > ~14M by moving to flatmem scheme. > > Cc: xe-kernel at external.cisco.com > Cc: Nikunj Kela > Signed-off-by: Nikunj Kela > --- > arch/arm64/Kconfig | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 42c090c..96ab9a7 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -775,6 +775,10 @@ config ARCH_SPARSEMEM_DEFAULT > config ARCH_SELECT_MEMORY_MODEL > def_bool ARCH_SPARSEMEM_ENABLE > > +config ARCH_FLATMEM_ENABLE > + def_bool y > + depends on !NUMA I still don't understand what this has to do with NUMA. SPARSEMEM is still going to be what you want on a non-NUMA system with large holes in the physical memory map, no? Will 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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7D2BC6778C for ; Fri, 6 Jul 2018 17:05:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7FA4D2075B for ; Fri, 6 Jul 2018 17:05:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7FA4D2075B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933969AbeGFRFi (ORCPT ); Fri, 6 Jul 2018 13:05:38 -0400 Received: from foss.arm.com ([217.140.101.70]:40402 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932776AbeGFRFh (ORCPT ); Fri, 6 Jul 2018 13:05:37 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1E98618A; Fri, 6 Jul 2018 10:05:37 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E4C503F2EA; Fri, 6 Jul 2018 10:05:36 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 7F3FA1AE37F8; Fri, 6 Jul 2018 18:06:17 +0100 (BST) Date: Fri, 6 Jul 2018 18:06:17 +0100 From: Will Deacon To: Nikunj Kela Cc: Catalin Marinas , xe-kernel@external.cisco.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] arm64: add ARM64-specific support for flatmem Message-ID: <20180706170617.GB4961@arm.com> References: <20180706170215.56116-1-nkela@cisco.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180706170215.56116-1-nkela@cisco.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 06, 2018 at 10:02:15AM -0700, Nikunj Kela wrote: > Flatmem is useful in reducing kernel memory usage. > One usecase is in kdump kernel. We are able to save > ~14M by moving to flatmem scheme. > > Cc: xe-kernel@external.cisco.com > Cc: Nikunj Kela > Signed-off-by: Nikunj Kela > --- > arch/arm64/Kconfig | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 42c090c..96ab9a7 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -775,6 +775,10 @@ config ARCH_SPARSEMEM_DEFAULT > config ARCH_SELECT_MEMORY_MODEL > def_bool ARCH_SPARSEMEM_ENABLE > > +config ARCH_FLATMEM_ENABLE > + def_bool y > + depends on !NUMA I still don't understand what this has to do with NUMA. SPARSEMEM is still going to be what you want on a non-NUMA system with large holes in the physical memory map, no? Will