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=-8.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 autolearn=unavailable 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 1E282C433E5 for ; Wed, 15 Jul 2020 16:01:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D3AAD20658 for ; Wed, 15 Jul 2020 16:01:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="WmDHlBA9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D3AAD20658 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 42DE86B0008; Wed, 15 Jul 2020 12:01:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3DE2D6B000D; Wed, 15 Jul 2020 12:01:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F48A6B000E; Wed, 15 Jul 2020 12:01:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0001.hostedemail.com [216.40.44.1]) by kanga.kvack.org (Postfix) with ESMTP id 191C06B0008 for ; Wed, 15 Jul 2020 12:01:18 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id A10E71EF2 for ; Wed, 15 Jul 2020 16:01:17 +0000 (UTC) X-FDA: 77040774594.08.fear19_4000cb426efa Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id 592591819E64A for ; Wed, 15 Jul 2020 16:00:55 +0000 (UTC) X-HE-Tag: fear19_4000cb426efa X-Filterd-Recvd-Size: 5316 Received: from aserp2120.oracle.com (aserp2120.oracle.com [141.146.126.78]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Wed, 15 Jul 2020 16:00:54 +0000 (UTC) Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06FFlEKq035568; Wed, 15 Jul 2020 16:00:48 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2020-01-29; bh=6UwNJBozS5Fm/gYrc3f/+HHTTdKUvXgAqHENd6eVNP4=; b=WmDHlBA9+S02t3dRwtZ9VfPlAbwlySN6lYtGSCqMaVxjC4ZCodpZN9hIJrpxNxUbEzqK 1PDKHAl5TxOEEcJpVMejURtJ7lSn1/WSdnrYMNidGVy0bgVLqsZVUUilIN1fch84/cKS r6IfF9ZZ/YI19gwQCcGxnZyAOBj1sLEgOEHrEmdgfv9t59iy8omhIxSs1QmdFQfXxzPb 95BmFO4oADnCGH9hI8/jhKz4UUurC+ngFzTEpKsmp3YdKkmpqza7w/eKyhxcAIQDAxuM hX5DIEk0IzHnNRADuJaDWM66IHSUrJoCfvWW81VZhOuvGRLRphd+gXneAZAeYqVc8qES og== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2120.oracle.com with ESMTP id 3275cmc9y5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 15 Jul 2020 16:00:48 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06FFlp2C114397; Wed, 15 Jul 2020 15:58:47 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3020.oracle.com with ESMTP id 32a4cqsrhg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 15 Jul 2020 15:58:47 +0000 Received: from abhmp0012.oracle.com (abhmp0012.oracle.com [141.146.116.18]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 06FFwjbB005043; Wed, 15 Jul 2020 15:58:45 GMT Received: from ca-dmjordan1.us.oracle.com (/10.211.9.48) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 15 Jul 2020 08:58:45 -0700 Date: Wed, 15 Jul 2020 11:59:13 -0400 From: Daniel Jordan To: David Hildenbrand Cc: Andrew Morton , Andy Lutomirski , Dave Hansen , Michal Hocko , Pavel Tatashin , Peter Zijlstra , Steven Sistare , Daniel Jordan , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] x86/mm: use max memory block size on bare metal Message-ID: <20200715155913.plxsu7h55xif2jic@ca-dmjordan1.us.oracle.com> References: <20200714205450.945834-1-daniel.m.jordan@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200714205450.945834-1-daniel.m.jordan@oracle.com> User-Agent: NeoMutt/20180716 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9683 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 mlxlogscore=999 spamscore=0 suspectscore=0 bulkscore=0 adultscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007150126 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9683 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 priorityscore=1501 bulkscore=0 adultscore=0 lowpriorityscore=0 phishscore=0 spamscore=0 impostorscore=0 malwarescore=0 mlxlogscore=999 clxscore=1015 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007150126 X-Rspamd-Queue-Id: 592591819E64A X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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 Tue, Jul 14, 2020 at 04:54:50PM -0400, Daniel Jordan wrote: > Some of our servers spend significant time at kernel boot initializing > memory block sysfs directories and then creating symlinks between them > and the corresponding nodes. The slowness happens because the machines > get stuck with the smallest supported memory block size on x86 (128M), > which results in 16,288 directories to cover the 2T of installed RAM. > The search for each memory block is noticeable even with > commit 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in > xarray to accelerate lookup"). > > Commit 078eb6aa50dc ("x86/mm/memory_hotplug: determine block size based > on the end of boot memory") chooses the block size based on alignment > with memory end. That addresses hotplug failures in qemu guests, but > for bare metal systems whose memory end isn't aligned to even the > smallest size, it leaves them at 128M. > > Make kernels that aren't running on a hypervisor use the largest > supported size (2G) to minimize overhead on big machines. Kernel boot > goes 7% faster on the aforementioned servers, shaving off half a second. > > Signed-off-by: Daniel Jordan > Cc: Andrew Morton > Cc: Andy Lutomirski > Cc: Dave Hansen > Cc: David Hildenbrand Darn. David, I forgot to add your ack from v2. My assumption is that it still stands after the minor change in this version, but please do correct me if I'm wrong.