From patchwork Mon Jun 13 12:31:59 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jisheng Zhang X-Patchwork-Id: 9172845 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1575360573 for ; Mon, 13 Jun 2016 12:38:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 07FFC21C9A for ; Mon, 13 Jun 2016 12:38:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F0965265B9; Mon, 13 Jun 2016 12:38:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7D16B21C9A for ; Mon, 13 Jun 2016 12:37:59 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1bCR6O-0005pF-Iq; Mon, 13 Jun 2016 12:36:24 +0000 Received: from mx0b-0016f401.pphosted.com ([67.231.156.173]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1bCR6L-0005bw-Py for linux-arm-kernel@lists.infradead.org; Mon, 13 Jun 2016 12:36:22 +0000 Received: from pps.filterd (m0045851.ppops.net [127.0.0.1]) by mx0b-0016f401.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u5DCRoVY012557; Mon, 13 Jun 2016 05:35:58 -0700 Received: from sc-exch04.marvell.com ([199.233.58.184]) by mx0b-0016f401.pphosted.com with ESMTP id 23gj5fdgt1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Mon, 13 Jun 2016 05:35:57 -0700 Received: from SC-EXCH04.marvell.com (10.93.176.84) by SC-EXCH04.marvell.com (10.93.176.84) with Microsoft SMTP Server (TLS) id 15.0.1104.5; Mon, 13 Jun 2016 05:35:56 -0700 Received: from maili.marvell.com (10.93.176.43) by SC-EXCH04.marvell.com (10.93.176.84) with Microsoft SMTP Server id 15.0.1104.5 via Frontend Transport; Mon, 13 Jun 2016 05:35:56 -0700 Received: from xhacker.marvell.com (unknown [10.37.130.169]) by maili.marvell.com (Postfix) with ESMTP id 70A5C3F703F; Mon, 13 Jun 2016 05:35:55 -0700 (PDT) From: Jisheng Zhang To: , Subject: [PATCH] arm64: mm: update SECTION_SIZE_BITS to 27 for 4k pagesize Date: Mon, 13 Jun 2016 20:31:59 +0800 Message-ID: <1465821119-3384-1-git-send-email-jszhang@marvell.com> X-Mailer: git-send-email 2.8.1 MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-06-13_06:, , signatures=0 X-Proofpoint-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606130141 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160613_053622_022693_E16FAE34 X-CRM114-Status: UNSURE ( 6.91 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jisheng Zhang , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP On one of my platforms, linux is given 1152MB memory. With current SECTION_SIZE_BITS 30, the reserved memmap is larger, it's a waste for us. Inspired by disscusion[1], reducing the SECTION_SIZE_BITS to 27 which means 128M section size saves us about 14MB, a huge gain for embeded memory constrained system. [1]http://lkml.iu.edu/hypermail/linux/kernel/1604.1/03036.html Signed-off-by: Jisheng Zhang --- arch/arm64/include/asm/sparsemem.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/include/asm/sparsemem.h b/arch/arm64/include/asm/sparsemem.h index 74a9d30..41c10f7 100644 --- a/arch/arm64/include/asm/sparsemem.h +++ b/arch/arm64/include/asm/sparsemem.h @@ -18,7 +18,11 @@ #ifdef CONFIG_SPARSEMEM #define MAX_PHYSMEM_BITS 48 +#ifdef CONFIG_ARM64_64K_PAGES #define SECTION_SIZE_BITS 30 +#else +#define SECTION_SIZE_BITS 27 +#endif #endif #endif