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=-11.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 D23EEC433E0 for ; Thu, 21 Jan 2021 05:29:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2E39223888 for ; Thu, 21 Jan 2021 05:29:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E39223888 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 42A7C6B0005; Thu, 21 Jan 2021 00:29:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3DB086B0007; Thu, 21 Jan 2021 00:29:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2A2CC6B0008; Thu, 21 Jan 2021 00:29:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0175.hostedemail.com [216.40.44.175]) by kanga.kvack.org (Postfix) with ESMTP id 168FC6B0005 for ; Thu, 21 Jan 2021 00:29:40 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id CFD7C180AD804 for ; Thu, 21 Jan 2021 05:29:39 +0000 (UTC) X-FDA: 77728654878.03.prose60_04108e127560 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin03.hostedemail.com (Postfix) with ESMTP id AFF7E28A4E8 for ; Thu, 21 Jan 2021 05:29:39 +0000 (UTC) X-HE-Tag: prose60_04108e127560 X-Filterd-Recvd-Size: 3949 Received: from m42-8.mailgun.net (m42-8.mailgun.net [69.72.42.8]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Thu, 21 Jan 2021 05:29:36 +0000 (UTC) DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1611206979; h=Content-Transfer-Encoding: MIME-Version: Message-Id: Date: Subject: Cc: To: From: Sender; bh=hfAxKpHRFM9Y26tV/QvUdyavnpRphrMju5aLp3NQ+4Y=; b=xlGTYpgfhpNIUepYqlDOKWwQAtRQAG2Y9OExvnMCQ0qZbDUNLRwrc85k/fWbqtt+lshVN9hW 6ZdxqKyBqqs2qlbK2Mx6MXVv74nSYyGZthx1Z/n7ghuv0UOW3wNUeQnZ2oKSca5zaB3ERCzy CrGcLkp8/aAusgcZN3VY9np6a54= X-Mailgun-Sending-Ip: 69.72.42.8 X-Mailgun-Sid: WyIwY2Q3OCIsICJsaW51eC1tbUBrdmFjay5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n02.prod.us-west-2.postgun.com with SMTP id 600911365677aca7bd782baa (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 21 Jan 2021 05:29:26 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 62B9FC43464; Thu, 21 Jan 2021 05:29:26 +0000 (UTC) Received: from th-lint-014.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: sudaraja) by smtp.codeaurora.org (Postfix) with ESMTPSA id 5BDA1C433C6; Thu, 21 Jan 2021 05:29:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 5BDA1C433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=sudaraja@codeaurora.org From: Sudarshan Rajagopalan To: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Anshuman Khandual , David Hildenbrand Cc: Sudarshan Rajagopalan Subject: [PATCH 0/1] arm64/sparsemem: reduce SECTION_SIZE_BITS Date: Wed, 20 Jan 2021 21:29:12 -0800 Message-Id: X-Mailer: git-send-email 2.25.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This patch is the follow-up from the discussions in the thread [1]. Reducing the section size has the merit of reducing wastage of reserved m= emory for vmmemmap mappings for sections with large memory holes. Also with sma= ller=20 section size gives more grunularity and agility for memory hot(un)pluggin= g. But there are also constraints in reducing SECTION_SIZE_BIT: - Should accommodate highest order page for a given config - Should not break PMD mapping in vmemmap for 4K pages - Should not consume too many page->flags bits reducing space for other i= nfo This patch uses the suggestions from Anshuman Khandual and David Hildenbr= and in thread [1] to set the least possible section size to 128MB for 4K and = 16K base page size configs for simplicity, and to 512MB for 64K base page siz= e config. [1] https://lore.kernel.org/lkml/cover.1609895500.git.sudaraja@codeaurora= .org/T/#m8ee60ae69db5e9eb06ca7999c43828d49ccb9626 Sudarshan Rajagopalan (1): arm64/sparsemem: reduce SECTION_SIZE_BITS arch/arm64/include/asm/sparsemem.h | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) --=20 Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project