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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 5F14FC63798 for ; Mon, 23 Nov 2020 22:02:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0145E20715 for ; Mon, 23 Nov 2020 22:02:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PaJdSMiw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730943AbgKWWCH (ORCPT ); Mon, 23 Nov 2020 17:02:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729668AbgKWWCG (ORCPT ); Mon, 23 Nov 2020 17:02:06 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0789C0613CF; Mon, 23 Nov 2020 14:02:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=mhCpis23NqY63c8NxX6Wxg38gWQuSreQ5clgMaAKViA=; b=PaJdSMiw4iN/I92Z9bYbMfvscb 9HdMsduPzdTIWJyB7e51N3arRZiy6S9g2BEVESuiG4aHlFqUVtzpiHADx5/vpdb4EsfqzxwQaJ501 8X4XZ1f5cae1Gtb2wfzzBtKYWL7eHl8h08lFMoGtaHk3ITOOet0NdKxNtaDLhK8dVho/V1FEmI6tA 6veew9XNjrE/VaddCQg6FI8xVBEcLcBX2HPiuKZyg3iAna/mlju19wC6xuBdRs/tvvZwJ74mYuWUm UrjkO13j9FbNlho28eMkAfhgPXwyhed3yB0Sd18s9qs6YQGExCsFAOXewM+LpBP5pCPAVNO8gNi0w dA3THayQ==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1khJtZ-0005K1-So; Mon, 23 Nov 2020 22:01:13 +0000 Date: Mon, 23 Nov 2020 22:01:13 +0000 From: Matthew Wilcox To: Mike Kravetz Cc: Michal Hocko , David Hildenbrand , Muchun Song , corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, rdunlap@infradead.org, oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, almasrymina@google.com, rientjes@google.com, osalvador@suse.de, song.bao.hua@hisilicon.com, duanxiongchun@bytedance.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v5 00/21] Free some vmemmap pages of hugetlb page Message-ID: <20201123220113.GW4327@casper.infradead.org> References: <20201120064325.34492-1-songmuchun@bytedance.com> <20201120084202.GJ3200@dhcp22.suse.cz> <6b1533f7-69c6-6f19-fc93-c69750caaecc@redhat.com> <20201120093912.GM3200@dhcp22.suse.cz> <55e53264-a07a-a3ec-4253-e72c718b4ee6@oracle.com> <20201123073842.GA27488@dhcp22.suse.cz> <37f4bf02-c438-9fbd-32ea-8bedbe30c4da@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <37f4bf02-c438-9fbd-32ea-8bedbe30c4da@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Nov 23, 2020 at 01:52:13PM -0800, Mike Kravetz wrote: > On 11/22/20 11:38 PM, Michal Hocko wrote: > > On Fri 20-11-20 09:45:12, Mike Kravetz wrote: > >> Not sure if I agree with that last statement. Database and virtualization > >> use cases from my employer allocate allocate hugetlb pages after boot. It > >> is shortly after boot, but still not from boot/kernel command line. > > > > Is there any strong reason for that? > > The reason I have been given is that it is preferable to have SW compute > the number of needed huge pages after boot based on total memory, rather > than have a sysadmin calculate the number and add a boot parameter. Oh, I remember this bug! I think it was posted publically, even. If the sysadmin configures, say, 90% of the RAM to be hugepages and then a DIMM fails and the sysadmin doesn't remember to adjust the boot parameter, Linux does some pretty horrible things and the symptom is "Linux doesn't boot".