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 41AE3C433F5 for ; Mon, 21 Mar 2022 14:51:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9B3706B0073; Mon, 21 Mar 2022 10:51:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 963146B0074; Mon, 21 Mar 2022 10:51:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7DD3C6B0075; Mon, 21 Mar 2022 10:51:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0038.hostedemail.com [216.40.44.38]) by kanga.kvack.org (Postfix) with ESMTP id 6F7956B0073 for ; Mon, 21 Mar 2022 10:51:53 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 23401A0A31 for ; Mon, 21 Mar 2022 14:51:53 +0000 (UTC) X-FDA: 79268682906.27.6588BFA Received: from mail-lj1-f174.google.com (mail-lj1-f174.google.com [209.85.208.174]) by imf12.hostedemail.com (Postfix) with ESMTP id 0D1514002D for ; Mon, 21 Mar 2022 14:51:51 +0000 (UTC) Received: by mail-lj1-f174.google.com with SMTP id c15so20177478ljr.9 for ; Mon, 21 Mar 2022 07:51:52 -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:content-transfer-encoding; bh=TzOy/qV3eezcboyjbLMN486a1kachnRta143Ruqmo98=; b=RgCgz9N89wVxPqzgD1TARrJ+FQKNCO4DN2bdkck8NUzgdy3JOH68iPGwCs650Is0st MVIC5KSvmYxkWxyWziJ6ip0YUGFa9Eb/VlQRhoQQlOPr+D/3lwQKy2HgngdU2rSdCkMB dJX4woel1uDhzDBU2v/xtr4VIlSZxtPVSs0UYL9PF7Q7Rm3KSDxSQ50uYki4Szf6q2aK WVf34MTfDwfSruPhgl7QeqJoMYDQcU4m0BVgbqrrzQ+JVxneY2H/7avJRZDzXVQ1MLEI I+zH09krGtchkdkc/Kfwaj2wOAzYyaDhJsZRbwIHZ8s6ofCW4WjqQPXHEJClQBdnkgzi Qpng== 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:content-transfer-encoding; bh=TzOy/qV3eezcboyjbLMN486a1kachnRta143Ruqmo98=; b=d4skvdsbot9L/n7qJ/kS47JpNTwg4sMBwz4JXCeg2VH5i+vbcx2fw/3XIU2M8SSCB9 fd8ksPYyj3f4oKSquAtsBpSMd6LNAqrviZyq3KeGPEUffLK6KyNTWGH+XuNGaHBcAIYw njoCkizcL+D+o63ijyHNvQdVyFEOuOxehSLAiPSjYw3W1Piz7rxZVPdmSNXJRmeYldVO 3sHh+vPAggvMlaCSxfYiR5R03VPqJSdxdFifZSyUAFQWM9iKQpw7/+Mr7lclSWY4DPmY QPIDBBGbZJld9KrKQQUb0MUN4ZJHn+ejl3oJtLdaxNp7SKQNUYLyAejT/5MO/lU/ZbPW 0Kmw== X-Gm-Message-State: AOAM532yDmgiV3WdGrBXfYvEg9b18jqwGZjd9SaF44V1VejRTyTfSI4v tWsnlUNDobUXgDLYWh6k2z9XLMGDRFsHVKkx5q/LBQ== X-Google-Smtp-Source: ABdhPJxUZN9+F7cvbQ0ddgtNOT1pSl++TJpfO81XpJ7v+jx4ajritmfwP4A4mRWdDJ8jVgx6XsmUwQBsIM8JSQ9Yox8= X-Received: by 2002:a2e:b008:0:b0:249:83ad:ab65 with SMTP id y8-20020a2eb008000000b0024983adab65mr4495344ljk.350.1647874310922; Mon, 21 Mar 2022 07:51:50 -0700 (PDT) MIME-Version: 1.0 References: <20220308213417.1407042-1-zokeefe@google.com> In-Reply-To: From: "Zach O'Keefe" Date: Mon, 21 Mar 2022 07:51:14 -0700 Message-ID: Subject: Re: [RFC PATCH 00/14] mm: userspace hugepage collapse To: Zi Yan Cc: Alex Shi , David Hildenbrand , David Rientjes , Michal Hocko , Pasha Tatashin , SeongJae Park , Song Liu , Vlastimil Babka , linux-mm@kvack.org, Andrea Arcangeli , Andrew Morton , Arnd Bergmann , Axel Rasmussen , Chris Kennelly , Chris Zankel , Helge Deller , Hugh Dickins , Ivan Kokshaysky , "James E.J. Bottomley" , Jens Axboe , "Kirill A. Shutemov" , Matthew Wilcox , Matt Turner , Max Filippov , Miaohe Lin , Minchan Kim , Patrick Xia , Pavel Begunkov , Peter Xu , Thomas Bogendoerfer , Yang Shi Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 0D1514002D X-Rspam-User: Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=RgCgz9N8; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf12.hostedemail.com: domain of zokeefe@google.com designates 209.85.208.174 as permitted sender) smtp.mailfrom=zokeefe@google.com X-Stat-Signature: bao1sq7wxwz9b1pqxgx5n9xx5zy1irwq X-Rspamd-Server: rspam04 X-HE-Tag: 1647874311-216477 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 21, 2022 at 7:32 AM Zi Yan wrote: > > On 8 Mar 2022, at 16:34, Zach O'Keefe wrote: > > > Introduction > > -------------------------------- > > > > This series provides a mechanism for userspace to induce a collapse of > > eligible ranges of memory into transparent hugepages in process context= , > > thus permitting users to more tightly control their own hugepage > > utilization policy at their own expense. > > > > This idea was previously introduced by David Rientjes, and thanks to > > everyone for your patience while I prepared these patches resulting fro= m > > that discussion[1]. > > > > [1] https://nam11.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2= Flore.kernel.org%2Fall%2FC8C89F13-3F04-456B-BA76-DE2C378D30BF%40nvidia.com%= 2F&data=3D04%7C01%7Cziy%40nvidia.com%7C7bcd2b7a8e4a424ab75908da014b76f9= %7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637823721375395857%7CUnknown%= 7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6M= n0%3D%7C3000&sdata=3D4bHCbskcQmp0Nu7ds7XCDFLty964672zCQPXILC25C8%3D&= ;reserved=3D0 > > > > Interface > > -------------------------------- > > > > The proposed interface adds a new madvise(2) mode, MADV_COLLAPSE, and > > Can we have a better name instead of MADV_COLLAPSE? It sounds like it is > destroying a huge page but in fact doing the opposite. Something like > MADV_CREATE_HUGE_PAGE? I know the kernel functions uses collapse everywhe= re > but it might be better not to confuse the user. > Hey Zi, thanks for reviewing / commenting. I briefly thought about "coalesce", but, "collapse" isn't just used within the kernel; it's already part of existing user apis such as the thp sysfs interface (/sys/kernel/mm/transparent_hugepage/khugepaged/pages_collapsed), vmstat (ex /proc/vmstat:thp_collapse_alloc[_failed]), per-memcg stats (memory.stat:thp_collapse_alloc) and tracepoints (ex mm_collapse_huge_page). I'm not married to it though. > Thanks. > > -- > Best Regards, > Yan, Zi