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 9B4D0C43334 for ; Wed, 20 Jul 2022 14:16:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3A1056B0073; Wed, 20 Jul 2022 10:16:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 32A636B0074; Wed, 20 Jul 2022 10:16:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1CD5E8E0001; Wed, 20 Jul 2022 10:16:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 0F6D86B0073 for ; Wed, 20 Jul 2022 10:16:49 -0400 (EDT) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id CD3B11A060E for ; Wed, 20 Jul 2022 14:16:48 +0000 (UTC) X-FDA: 79707679296.22.DC3DE0F Received: from mail2.intersystems.com (mail2.intersystems.com [38.105.105.84]) by imf07.hostedemail.com (Postfix) with SMTP id EDE0740061 for ; Wed, 20 Jul 2022 14:16:47 +0000 (UTC) X-InterSystems: Sent from InterSystems X-InterSystems: Sent from InterSystems X-InterSystems: Sent from InterSystems X-InterSystems: Sent from InterSystems From: Ray Fucillo To: Mike Kravetz CC: linux-mm , "linux-kernel@vger.kernel.org" , Muchun Song , Michal Hocko , Peter Xu , Naoya Horiguchi , David Hildenbrand , "Aneesh Kumar K . V" , Andrea Arcangeli , "Kirill A . Shutemov" , Davidlohr Bueso , Prakash Sangappa , James Houghton , Mina Almasry , "Pasha Tatashin" , Axel Rasmussen , Ray Fucillo , Andrew Morton Subject: Re: [RFC PATCH v4 0/8] hugetlb: Change huge pmd sharing synchronization again Thread-Topic: [RFC PATCH v4 0/8] hugetlb: Change huge pmd sharing synchronization again Thread-Index: AQHYkXZV7rwY/0b1YEWM7yXbYs48gK2HptEA Date: Wed, 20 Jul 2022 14:16:46 +0000 Message-ID: <3F53322F-65B0-4DA0-84AB-360CB46769E4@intersystems.com> References: <20220706202347.95150-1-mike.kravetz@oracle.com> In-Reply-To: <20220706202347.95150-1-mike.kravetz@oracle.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [172.17.254.204] x-c2processedorg: 5d7e5ca7-6395-445f-80da-8568a4fc58e5 Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intersystems.com (policy=none); spf=none (imf07.hostedemail.com: domain of Ray.Fucillo@intersystems.com has no SPF policy when checking 38.105.105.84) smtp.mailfrom=Ray.Fucillo@intersystems.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1658326608; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=D8sbtM9aPjNBuGXsNYYIxFRLXMOPSCefFA3Y1k2m9rU=; b=2VkpTQJSiEoaR+HAfrmZ0lBxwMlC4FhsXExdCzU0rkxCJKGnP5Zm2hizgX4yF5H1Lx8mZH LM4fBncKl3yqbUVorpbWlkY6VIiU3OOk9O+agTnMbG8XmyfdaXHUvKY8wEKJLIuRCqZsQC MkVFbBEC0xXLRRGr77CcDIkpANW6s6k= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1658326608; a=rsa-sha256; cv=none; b=Amh6LWXQAwZc+i5XWt/YZfZTeq+vO4YBivsOqusOYtnKtOYzQCQnlVZ0wd77urYAejePna 0h9iVyOdg6St/2dTOEHhoCSr7cmKwwUuDJjJ1Akbx8QlYJ/+oL3jpz+z6EQ03TP5w+09ya DEpCqXZhOA6+QsdFRTGAn73WHlasO5Y= X-Stat-Signature: 9pu48r1u6ierjjd9ggbjmorp8ue41k1p X-Rspamd-Queue-Id: EDE0740061 X-Rspamd-Server: rspam08 Authentication-Results: imf07.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intersystems.com (policy=none); spf=none (imf07.hostedemail.com: domain of Ray.Fucillo@intersystems.com has no SPF policy when checking 38.105.105.84) smtp.mailfrom=Ray.Fucillo@intersystems.com X-Rspam-User: X-HE-Tag: 1658326607-446704 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 Jul 6, 2022, at 4:23 PM, Mike Kravetz wrote: >=20 > I am sending this as a RFC once more in the hope of generating comments > and discussion. While the changes are intrusive, they do show a significa= nt > performance benefit in my simulated workload. Code is based on next-20220= 706. >=20 > hugetlb fault scalability regressions have recently been reported [1]. > This is not the first such report, as regressions were also noted when > commit c0d0381ade79 ("hugetlbfs: use i_mmap_rwsem for more pmd sharing > synchronization") was added [2] in v5.7. At that time, a proposal to > address the regression was suggested [3] but went nowhere. >=20 > The regression and benefit of this patch series is not evident when > using the vm_scalability benchmark reported in [2] on a recent kernel. > Results from running, Mike, thank you for all the work and careful consideration here! We did fi= nd that this patch set addresses the scalability regression that was at the= root of critical issues for customers that upgraded to newer Linux distrib= utions (those with commit c0d0381ade79) Ray=