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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 7D2E4C433DB for ; Thu, 21 Jan 2021 10:09:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3437D221F0 for ; Thu, 21 Jan 2021 10:09:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728517AbhAUKJX (ORCPT ); Thu, 21 Jan 2021 05:09:23 -0500 Received: from gentwo.org ([3.19.106.255]:52784 "EHLO gentwo.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728657AbhAUKJI (ORCPT ); Thu, 21 Jan 2021 05:09:08 -0500 Received: by gentwo.org (Postfix, from userid 1002) id A245C3F04E; Thu, 21 Jan 2021 10:08:17 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id A030D3EFF6; Thu, 21 Jan 2021 10:08:17 +0000 (UTC) Date: Thu, 21 Jan 2021 10:08:17 +0000 (UTC) From: Christoph Lameter X-X-Sender: cl@www.lameter.com To: Sudarshan Rajagopalan cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Anshuman Khandual , David Hildenbrand , Mike Rapoport , Mark Rutland , Logan Gunthorpe , Andrew Morton , Steven Price , Suren Baghdasaryan Subject: Re: [PATCH 1/1] arm64/sparsemem: reduce SECTION_SIZE_BITS In-Reply-To: <43843c5e092bfe3ec4c41e3c8c78a7ee35b69bb0.1611206601.git.sudaraja@codeaurora.org> Message-ID: References: <43843c5e092bfe3ec4c41e3c8c78a7ee35b69bb0.1611206601.git.sudaraja@codeaurora.org> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 20 Jan 2021, Sudarshan Rajagopalan wrote: > But there are other problems in reducing SECTION_SIZE_BIT. Reducing it by too > much would over populate /sys/devices/system/memory/ and also consume too many > page->flags bits in the !vmemmap case. Also section size needs to be multiple > of 128MB to have PMD based vmemmap mapping with CONFIG_ARM64_4K_PAGES. There is also the issue of requiring more space in the TLB cache with smaller page sizes. Or does ARM resolve these into smaller TLB entries anyways (going on my x86 kwon how here)? Anyways if there are only a few TLB entries then the effect could be significant. 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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 AF8C5C433DB for ; Thu, 21 Jan 2021 10:08:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 193E5239E4 for ; Thu, 21 Jan 2021 10:08:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 193E5239E4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3EA3E6B0005; Thu, 21 Jan 2021 05:08:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 373BB6B0007; Thu, 21 Jan 2021 05:08:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 23C856B0008; Thu, 21 Jan 2021 05:08:19 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0102.hostedemail.com [216.40.44.102]) by kanga.kvack.org (Postfix) with ESMTP id 089EF6B0005 for ; Thu, 21 Jan 2021 05:08:19 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id B3DC4180AD81D for ; Thu, 21 Jan 2021 10:08:18 +0000 (UTC) X-FDA: 77729357076.07.cent18_0d0de4327562 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id 96FED1803F9BE for ; Thu, 21 Jan 2021 10:08:18 +0000 (UTC) X-HE-Tag: cent18_0d0de4327562 X-Filterd-Recvd-Size: 2253 Received: from gentwo.org (gentwo.org [3.19.106.255]) by imf38.hostedemail.com (Postfix) with ESMTP for ; Thu, 21 Jan 2021 10:08:18 +0000 (UTC) Received: by gentwo.org (Postfix, from userid 1002) id A245C3F04E; Thu, 21 Jan 2021 10:08:17 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id A030D3EFF6; Thu, 21 Jan 2021 10:08:17 +0000 (UTC) Date: Thu, 21 Jan 2021 10:08:17 +0000 (UTC) From: Christoph Lameter X-X-Sender: cl@www.lameter.com To: Sudarshan Rajagopalan cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Anshuman Khandual , David Hildenbrand , Mike Rapoport , Mark Rutland , Logan Gunthorpe , Andrew Morton , Steven Price , Suren Baghdasaryan Subject: Re: [PATCH 1/1] arm64/sparsemem: reduce SECTION_SIZE_BITS In-Reply-To: <43843c5e092bfe3ec4c41e3c8c78a7ee35b69bb0.1611206601.git.sudaraja@codeaurora.org> Message-ID: References: <43843c5e092bfe3ec4c41e3c8c78a7ee35b69bb0.1611206601.git.sudaraja@codeaurora.org> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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: On Wed, 20 Jan 2021, Sudarshan Rajagopalan wrote: > But there are other problems in reducing SECTION_SIZE_BIT. Reducing it by too > much would over populate /sys/devices/system/memory/ and also consume too many > page->flags bits in the !vmemmap case. Also section size needs to be multiple > of 128MB to have PMD based vmemmap mapping with CONFIG_ARM64_4K_PAGES. There is also the issue of requiring more space in the TLB cache with smaller page sizes. Or does ARM resolve these into smaller TLB entries anyways (going on my x86 kwon how here)? Anyways if there are only a few TLB entries then the effect could be significant. 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=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 2C4F0C433E0 for ; Thu, 21 Jan 2021 10:09:57 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B143B221F0 for ; Thu, 21 Jan 2021 10:09:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B143B221F0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:Message-ID:In-Reply-To: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Yx5J/qOm+kGLRXNx6QnuxE6kQKjG687lz6CmcknXk4A=; b=d/Ih1CCcWUvfj9Hrv0dvx3yjM +wDamoPGqlwT6nOIDsV5ZI6rTXFXu6x7nvNcxFRm1FAg2T5/KMqJf00J+wdGP/2f9G0DpRvekfam3 Dz09OFMVaVH5R3eqVigSFUmmHzfVT0L2q9awV++0tMjuWMO0UdzgQFDX4tDYsNwjjosm8C6XlTCo5 XE9iAIGyeqNOwAc+1rwSiXGSUyWEAMxV8d43EI1+NN5ITlftpxFsW0wCmE8l8ka+kSqpo808PM9aS cgxVcbdTuryJ/WNznqEzvWZKOCHJu0ER9LHmn9nvhJMPTUW+2YVY1u0l+HN1C7lU9dPfUNVhlAG1y c529zjRYQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2Wt8-0001od-Jn; Thu, 21 Jan 2021 10:08:26 +0000 Received: from gentwo.org ([3.19.106.255]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2Wt4-0001ng-P5 for linux-arm-kernel@lists.infradead.org; Thu, 21 Jan 2021 10:08:24 +0000 Received: by gentwo.org (Postfix, from userid 1002) id A245C3F04E; Thu, 21 Jan 2021 10:08:17 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id A030D3EFF6; Thu, 21 Jan 2021 10:08:17 +0000 (UTC) Date: Thu, 21 Jan 2021 10:08:17 +0000 (UTC) From: Christoph Lameter X-X-Sender: cl@www.lameter.com To: Sudarshan Rajagopalan Subject: Re: [PATCH 1/1] arm64/sparsemem: reduce SECTION_SIZE_BITS In-Reply-To: <43843c5e092bfe3ec4c41e3c8c78a7ee35b69bb0.1611206601.git.sudaraja@codeaurora.org> Message-ID: References: <43843c5e092bfe3ec4c41e3c8c78a7ee35b69bb0.1611206601.git.sudaraja@codeaurora.org> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210121_050822_836945_01546FFE X-CRM114-Status: UNSURE ( 9.67 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Anshuman Khandual , Catalin Marinas , David Hildenbrand , linux-kernel@vger.kernel.org, Mike Rapoport , Suren Baghdasaryan , linux-mm@kvack.org, Logan Gunthorpe , Andrew Morton , Steven Price , Will Deacon , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 20 Jan 2021, Sudarshan Rajagopalan wrote: > But there are other problems in reducing SECTION_SIZE_BIT. Reducing it by too > much would over populate /sys/devices/system/memory/ and also consume too many > page->flags bits in the !vmemmap case. Also section size needs to be multiple > of 128MB to have PMD based vmemmap mapping with CONFIG_ARM64_4K_PAGES. There is also the issue of requiring more space in the TLB cache with smaller page sizes. Or does ARM resolve these into smaller TLB entries anyways (going on my x86 kwon how here)? Anyways if there are only a few TLB entries then the effect could be significant. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel