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 CBBD3C61DA4 for ; Wed, 22 Feb 2023 20:57:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5626F6B0072; Wed, 22 Feb 2023 15:57:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 512A06B0073; Wed, 22 Feb 2023 15:57:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3DA636B0075; Wed, 22 Feb 2023 15:57:41 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 31BD56B0072 for ; Wed, 22 Feb 2023 15:57:41 -0500 (EST) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 0953540D38 for ; Wed, 22 Feb 2023 20:57:41 +0000 (UTC) X-FDA: 80496139122.28.F484109 Received: from mail-vs1-f44.google.com (mail-vs1-f44.google.com [209.85.217.44]) by imf13.hostedemail.com (Postfix) with ESMTP id 59ED92001B for ; Wed, 22 Feb 2023 20:57:39 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=QrN6VLuo; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf13.hostedemail.com: domain of almasrymina@google.com designates 209.85.217.44 as permitted sender) smtp.mailfrom=almasrymina@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1677099459; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=XO/60+i0K11q3bhzf+PVd34dhBLRH4Ix6IhGCPR4Tec=; b=Yb+Rj9m+o6HakZBGaQ2iITg/s3F02EsKYh6lxWeiOoSf0WT9S1BQbejwdqK6pnXbfaSJ7V 4BDOHTLymOjNEy4P6AEdrxdB8Uog5SpSaVyqs/RpHVsORV7JTxy3RHFDSF9VvMbLsZGo4j zkGqOelE0PJCNOjLtKwJPWg02wqsYhA= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=QrN6VLuo; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf13.hostedemail.com: domain of almasrymina@google.com designates 209.85.217.44 as permitted sender) smtp.mailfrom=almasrymina@google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1677099459; a=rsa-sha256; cv=none; b=lrD8lsr383452V6c4hhun3ep7WR6CU5icjcLSdUV+kTvAIzJqbfS5pUYbFcpbwqZrqfhiv kh4A/Zu9KRI/w5t1isPsHnfnISOH6DXat15jKNG2/Wg1ojU+mcdt++I42TOuRHHIrilMP1 /rc67zkQ3XlRV+JNSQwAZKWltQB/cr4= Received: by mail-vs1-f44.google.com with SMTP id v3so11108490vse.0 for ; Wed, 22 Feb 2023 12:57:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1677099458; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=XO/60+i0K11q3bhzf+PVd34dhBLRH4Ix6IhGCPR4Tec=; b=QrN6VLuokAQJAgYd4+9Ank3gXSQtBlR+BGp8tdzFBFHzVmKsqPNfZ9hZUAS6d91d2X Ce+X5eX93odULB/j44/FsEcw7uULYFMhGaFUbmNFvOB6ePPUQaHzoY8V6TK/Za085/0l 8xICacb6e3cBuA/X8iGZsN9862zyk5v0nkAg83hqRkbT6U2Ur3MVcoYz16fSg5p0grsK oLRaObuNUn9QILiAWwbn+/ikkDqYzHCgzA6/Cunb1mi8tsk4ksb0pDTLqpNQDaZCrrP8 Hzl25ucZoHqIvkgTUX28SFOmHFYXo9w3XaA77I7S4ZWT+jUQMpzegwvGcYBpWLvyAuhl MTVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677099458; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=XO/60+i0K11q3bhzf+PVd34dhBLRH4Ix6IhGCPR4Tec=; b=YZ+6K76MlgucoHUmMSg6HVcK6j2RgD30FJklX+6nyXbIwZAKE6s0gTKKhEU8FXlukX AlGEU7vNC+sZIL+TVPUQGAAe5WwXmYjs+O6stBXofJ3plOj+93iApvgL677gNpYPUiiA IJRyevSvSyWqdiOaqMkmsk2qa8TAdFJTxuMlLl+tzpDpoIlMN3YqIYhu+THT7bA9oFmd l2R4h2cnEs9MlLmHX5dzV3COpjO0y63aRrwTjt/L/VWlcgp3O9uvJ07C1HwGSvH9LYgF G9fe0PaUR3blQLBN0dYxaoLPUiinVsiMdSmLDi3M+j3nkGsSYwuWWVygvbsmOLyPC6Aw L/DQ== X-Gm-Message-State: AO0yUKVH0dsMVJ/d/4/kYJGwo/raEQq7PNalwb6vqvu+SHMvBhTRipKh 8+W3kFyNGE14mi5N+9g9sTK60/HpiGi1UewU26pyoQ== X-Google-Smtp-Source: AK7set9+P+EVsDhs4PBijx8RrqiWI/mDw4GXQvb8TvyeO5ATbT4qXZzQsMAnrfq4Eu4pse8Ds+VKoDCFv/m3JBR0zzk= X-Received: by 2002:a05:6102:23f6:b0:3c8:6949:ea4c with SMTP id p22-20020a05610223f600b003c86949ea4cmr2233390vsc.76.1677099458355; Wed, 22 Feb 2023 12:57:38 -0800 (PST) MIME-Version: 1.0 References: <20230218002819.1486479-1-jthoughton@google.com> <28a7208c-939c-19ea-1cf0-298444dffe85@redhat.com> In-Reply-To: <28a7208c-939c-19ea-1cf0-298444dffe85@redhat.com> From: Mina Almasry Date: Wed, 22 Feb 2023 12:57:27 -0800 Message-ID: Subject: Re: [PATCH v2 00/46] hugetlb: introduce HugeTLB high-granularity mapping To: David Hildenbrand Cc: Mike Kravetz , James Houghton , Muchun Song , Peter Xu , Andrew Morton , David Rientjes , Axel Rasmussen , "Zach O'Keefe" , Manish Mishra , Naoya Horiguchi , "Dr . David Alan Gilbert" , "Matthew Wilcox (Oracle)" , Vlastimil Babka , Baolin Wang , Miaohe Lin , Yang Shi , Frank van der Linden , Jiaqi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 59ED92001B X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: 1ygqef1cuk54pr39dj7b5embjzh1eouj X-HE-Tag: 1677099459-610490 X-HE-Meta: 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 Dh3BefC9 3K4n9Bv6ecm6vr1ewLcNStK5TDLllWztJtK0dSLBfTZg5Iek6wjOqaCmD4YJ3TbZV1k6GULY9gqFv4SFye7SSM/nGC/783uFAPvqVFHJ2KDfk9As7ikOBHDLkawa6kSt0+Em0nFhq/mQ+bRkA4G0kBCPXfa2MGjZIq3B/cFYL21iGSt+glej9PLS5N5r1SECzxI+bI9XIBRrn90rp84UYsmM+NVJsk2GEDauT5Clvmf6UfmHzUnZb3QwNB8OFYrxaPtmen+1LKTKHM3HUjl5WGMoteB1yJGgdTdOAEkCD0nv2/ZjSPs8ATsDlkfKUPEWP61oZoYkhxIgShBIyNJ+8KQ4bPFJzyMQYHY9J 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, Feb 22, 2023 at 7:49 AM David Hildenbrand wrote: > > On 21.02.23 22:46, Mike Kravetz wrote: > > On 02/18/23 00:27, James Houghton wrote: > >> This series introduces the concept of HugeTLB high-granularity mapping > >> (HGM). This series teaches HugeTLB how to map HugeTLB pages at > >> high-granularity, similar to how THPs can be PTE-mapped. > >> > >> Support for HGM in this series is for MAP_SHARED VMAs on x86_64 only. Other > >> architectures and (some) support for MAP_PRIVATE will come later. > >> > >> This series is based on latest mm-unstable (ccd6a73daba9). > >> > >> Notable changes with this series > >> ================================ > >> > >> - hugetlb_add_file_rmap / hugetlb_remove_rmap are added to handle > >> mapcounting for non-anon hugetlb. > >> - The mapcounting scheme uses subpages' mapcounts for high-granularity > >> mappings, but it does not use subpages_mapcount(). This scheme > >> prevents the HugeTLB VMEMMAP optimization from being used, so it > >> will be improved in a later series. > >> - page_add_file_rmap and page_remove_rmap are updated so they can be > >> used by hugetlb_add_file_rmap / hugetlb_remove_rmap. > >> - MADV_SPLIT has been added to enable the userspace API changes that > >> HGM allows for: high-granularity UFFDIO_CONTINUE (and maybe other > >> changes in the future). MADV_SPLIT does NOT force all the mappings to > >> be PAGE_SIZE. > >> - MADV_COLLAPSE is expanded to include HugeTLB mappings. > >> > >> Old versions: > >> v1: https://lore.kernel.org/linux-mm/20230105101844.1893104-1-jthoughton@google.com/ > >> RFC v2: https://lore.kernel.org/linux-mm/20221021163703.3218176-1-jthoughton@google.com/ > >> RFC v1: https://lore.kernel.org/linux-mm/20220624173656.2033256-1-jthoughton@google.com/ > >> > >> Changelog: > >> v1 -> v2 (thanks Peter for all your suggestions!): > >> - Changed mapcount to be more THP-like, and make HGM incompatible with > >> HVO. > >> - HGM is now disabled by default to leave HVO enabled by default. > > > > I understand the reasoning behind the move to THP-like mapcounting, and the > > incompatibility with HVO. However, I just got to patch 5 and realized either > > HGM or HVO will need to be chosen at kernel build time. That may not be an > > issue for cloud providers or others building their own kernels for internal > > use. However, distro kernels will need to pick one option or the other. > > Right now, my Fedora desktop has HVO enabled so it would likely not have > > HGM enabled. That is not a big deal for a desktop. > > > > Just curious, do we have distro kernel users that want to use HGM? > > Most certainly I would say :) > Is it a blocker to merge in an initial implementation though? Do distro kernel users have a pressing need for HVO + HGM used in tandem? > -- > Thanks, > > David / dhildenb >