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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=no 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 A9824C433E0 for ; Thu, 9 Jul 2020 13:44:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 740CC20772 for ; Thu, 9 Jul 2020 13:44:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594302261; bh=v6Vn1YgNxBgfgcIxWirvzy4yRH6zVpQpKkve958MzHg=; h=From:To:Cc:Subject:Date:List-ID:From; b=sXDLT+VcwfFl3sjgEpoKbRGT+3P+GFRnlDHOHhBEludwrH6lqyWTNM23mug3yyAjd 0XhZGPmoFQ2bE23iRltcSXqv7Tl57u0bfUEMKL/VIGwBVxEXfs1yv/4lEnQ1MAf2dE wA63JTEXoEld3FAVu/OtUL1fPAzCDuh5SefxFeWE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727101AbgGINoU (ORCPT ); Thu, 9 Jul 2020 09:44:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:60188 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726340AbgGINoT (ORCPT ); Thu, 9 Jul 2020 09:44:19 -0400 Received: from hump.s81c.com (unknown [87.71.40.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B524D20772; Thu, 9 Jul 2020 13:44:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594302258; bh=v6Vn1YgNxBgfgcIxWirvzy4yRH6zVpQpKkve958MzHg=; h=From:To:Cc:Subject:Date:From; b=lMjqciFNM1a9a8XnYPdfLoueKSxMVUUC04xe4cfAyGXumRmM6Jtyvobso2Qakeuwj sIBHMI9VZIZgtHqb9wOAov5RLIq1Uaq8+D3D6esAvdXjKms88zyMXvasGLfDo4XMAb U8RBe2jWwmIDfdzAvZCLYWce/w9R6DPhHMJw9q1g= From: Mike Rapoport To: Vineet Gupta Cc: Eugeniy Paltsev , Mike Rapoport , linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org, Mike Rapoport Subject: [RFC/RFT PATCH v2 0/1] arc: add sparsemem support Date: Thu, 9 Jul 2020 16:44:11 +0300 Message-Id: <20200709134412.1464453-1-rppt@kernel.org> X-Mailer: git-send-email 2.25.4 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mike Rapoport Hi, It took me a while to get back to it, but better late than never :) This patch adds SPARSEMEM support as an alternative to DISCONTIGMEM in the case when there are two DRAM banks populated. I've verified that it boots on nsim, but I could not find a way to make nsim emulate two memory banks. There is slight improvement in the resulting kernel size for nsim_700_defconfig with CONFIG_HIGHMEM=y. If sparse actually works on a system with 2 DRAM banks and does not introduce performance regression, I suggest to update this patch to replace DISCONTIGMEM with SPARSEMEM on arc. $ size discontig/vmlinux sparse/vmlinux text data bss dec hex filename 3894379 1093092 244932 5232403 4fd713 discontig/vmlinux 3879040 1093964 244956 5217960 4f9ea8 sparse/vmlinux $ ./scripts/bloat-o-meter ~/tmp/arc/discontig/vmlinux ~/tmp/arc/sparse/vmlinux add/remove: 35/23 grow/shrink: 35/384 up/down: 8110/-26438 (-18328) ... Total: Before=4282217, After=4263889, chg -0.43% Mike Rapoport (1): arc: add sparsemem support arch/arc/Kconfig | 10 ++++++++++ arch/arc/include/asm/sparsemem.h | 13 +++++++++++++ arch/arc/mm/init.c | 7 ++++++- 3 files changed, 29 insertions(+), 1 deletion(-) create mode 100644 arch/arc/include/asm/sparsemem.h -- 2.26.2