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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23B69C433EF for ; Tue, 15 Mar 2022 00:50:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 658F38D0003; Mon, 14 Mar 2022 20:50:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 608258D0001; Mon, 14 Mar 2022 20:50:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4A8DD8D0003; Mon, 14 Mar 2022 20:50:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0147.hostedemail.com [216.40.44.147]) by kanga.kvack.org (Postfix) with ESMTP id 3B0408D0001 for ; Mon, 14 Mar 2022 20:50:21 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id E00128248076 for ; Tue, 15 Mar 2022 00:50:20 +0000 (UTC) X-FDA: 79244789400.20.8A3F29C Received: from mail-vs1-f45.google.com (mail-vs1-f45.google.com [209.85.217.45]) by imf15.hostedemail.com (Postfix) with ESMTP id 70F49A0005 for ; Tue, 15 Mar 2022 00:50:20 +0000 (UTC) Received: by mail-vs1-f45.google.com with SMTP id u82so19159066vsu.0 for ; Mon, 14 Mar 2022 17:50:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=TGWP/j9jQDz8ITNZjF9Mi8AuvhWKnrJvGLZgMJstMyM=; b=CfS7UUjvLrAT1aDGYV3HnxSl8EQtbmuYuPBgTmaQYFz9vJimhbOWc+IH0w9b5GdliA mHycmaQ42AeBz9Run7QRKkijkzuuXe/k4wG3L3HFkHZHxIBQpp8MnzKygxU4iwixKfT6 nORrYwSyj8T0AVOhVnvyQjHf7uFM6uTZfIcyPyr3tJO5Yiat5KQ0XdDbvQQhBCTnq/dN MppfA+kUUjiUpIDzqmo6ULH6hF5gFIzU2wFX9+1UGraZQIkxwy9XqrNvVMBciDx3dxqx ZfhQmEtcCIW+Hrvaqj6jda+tfyYebGiiPej6g5M7HQMMiHUBUvAsBcSGTY7JohJz/mR3 q82A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=TGWP/j9jQDz8ITNZjF9Mi8AuvhWKnrJvGLZgMJstMyM=; b=wf0ndhBkOIaLbB4DoVQLGrjQisbsxR5/ejt3gp3sxYvPgiNOYBuOZQIWIb2z25acVz NsYA+dED4Q/iL4co/x5tmiiiB2u6CDpYgDpwi+7UsNheeBPhESwA/JKhAubRecR9wxdQ HQNoPdrBYqeowkqcHDt7TR80cWHi0qA/ZAG8JI9tk5gaYH5j3Gza12wtVtW0rLo9hqtR Z6vdUMy8/1bYyAjrwRs4f60r9dKoBALSdx8iD8rwOsf44SUfS1IASRDu9m6qsHAqtHJv hMwsq8Mgvb60a8ppBQvLCvjiUSM+umBclmi1Dsa9Cm5sbOdfzrff4RbDkbEGtGiNLuH/ PHSg== X-Gm-Message-State: AOAM533XTtSzvUFHTEK/xvb16oU/HqK+EnPcRItuNGJwYw+UWgkZgi7i Kw2v4OZP1vKEXRlGgr/BAWb8VSpfCA9BBXWLQMpNPw== X-Google-Smtp-Source: ABdhPJx0othUKamJYw7fkq4YIMuB/hB8vElbG97cfyPOzYEEeFJqxq2EgYGx7cZnSaYaYnniHc3DsVySI8hwoEtt7Bs= X-Received: by 2002:a05:6102:290c:b0:322:b864:22f5 with SMTP id cz12-20020a056102290c00b00322b86422f5mr7717062vsb.41.1647305419517; Mon, 14 Mar 2022 17:50:19 -0700 (PDT) MIME-Version: 1.0 References: <20220309021230.721028-1-yuzhao@google.com> <20220309021230.721028-6-yuzhao@google.com> <875yoh552i.fsf@yhuang6-desk2.ccr.corp.intel.com> <87mths3vg5.fsf@yhuang6-desk2.ccr.corp.intel.com> In-Reply-To: <87mths3vg5.fsf@yhuang6-desk2.ccr.corp.intel.com> From: Yu Zhao Date: Mon, 14 Mar 2022 18:50:08 -0600 Message-ID: Subject: Re: [PATCH v9 05/14] mm: multi-gen LRU: groundwork To: "Huang, Ying" Cc: kernel@lists.fedoraproject.org, kernel-team@lists.ubuntu.com, Andrew Morton , Linus Torvalds , Andi Kleen , Aneesh Kumar , Catalin Marinas , Dave Hansen , Hillf Danton , Jens Axboe , Jesse Barnes , Johannes Weiner , Jonathan Corbet , Matthew Wilcox , Mel Gorman , Michael Larabel , Michal Hocko , Mike Rapoport , Rik van Riel , Vlastimil Babka , Will Deacon , Linux ARM , "open list:DOCUMENTATION" , linux-kernel , Linux-MM , Kernel Page Reclaim v2 , "the arch/x86 maintainers" , Brian Geffon , Jan Alexander Steffens , Oleksandr Natalenko , Steven Barrett , Suleiman Souhlal , Daniel Byrne , Donald Carr , =?UTF-8?Q?Holger_Hoffst=C3=A4tte?= , Konstantin Kharlamov , Shuang Zhai , Sofia Trinh , Vaibhav Jain Content-Type: text/plain; charset="UTF-8" X-Rspam-User: Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=CfS7UUjv; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf15.hostedemail.com: domain of yuzhao@google.com designates 209.85.217.45 as permitted sender) smtp.mailfrom=yuzhao@google.com X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 70F49A0005 X-Stat-Signature: qhubx1g73xhxnjbn6zpwaexk6xtbeirn X-HE-Tag: 1647305420-189355 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 Mon, Mar 14, 2022 at 6:34 PM Huang, Ying wrote: > > Yu Zhao writes: > > > On Mon, Mar 14, 2022 at 2:09 AM Huang, Ying wrote: > >> > >> Hi, Yu, > >> > >> Yu Zhao writes: > >> > diff --git a/mm/Kconfig b/mm/Kconfig > >> > index 3326ee3903f3..747ab1690bcf 100644 > >> > --- a/mm/Kconfig > >> > +++ b/mm/Kconfig > >> > @@ -892,6 +892,16 @@ config ANON_VMA_NAME > >> > area from being merged with adjacent virtual memory areas due to the > >> > difference in their name. > >> > > >> > +# the multi-gen LRU { > >> > +config LRU_GEN > >> > + bool "Multi-Gen LRU" > >> > + depends on MMU > >> > + # the following options can use up the spare bits in page flags > >> > + depends on !MAXSMP && (64BIT || !SPARSEMEM || SPARSEMEM_VMEMMAP) > >> > >> LRU_GEN depends on !MAXSMP. So, What is the maximum NR_CPUS supported > >> by LRU_GEN? > > > > LRU_GEN doesn't really care about NR_CPUS. IOW, it doesn't impose a > > max number. The dependency is with NODES_SHIFT selected by MAXSMP: > > default "10" if MAXSMP > > This combined with LAST_CPUPID_SHIFT can exhaust the spare bits in page flags. > > From the following code snippets from page-flags-layout.h, > LAST_CPUPID_SHIFT is related to NR_CPUS instead of NODES_SHIFT. It is. But LAST_CPUPID_NOT_IN_PAGE_FLAGS should always work but NODE_NOT_IN_PAGE_FLAGS doesn't.