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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 9DCB8C433E0 for ; Thu, 4 Mar 2021 17:24:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6ADD464F57 for ; Thu, 4 Mar 2021 17:24:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236819AbhCDRXd (ORCPT ); Thu, 4 Mar 2021 12:23:33 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:21824 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234267AbhCDRX1 (ORCPT ); Thu, 4 Mar 2021 12:23:27 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614878521; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NQatpNWGE4o3s3KgiODLTmG3DHd1ZX49JLUXKjotVm8=; b=ZOswHyuHCU5lPaTzMSZuXGiUbueFuhjWecwqQ6jzOqycr9Xt+k1GA+dXEP+Ed5kWVRfxgL e6o2CZEo66UAmLcxeIvHtXlP9+aDfGDD9t4NMVX1YC5IveWzlU4IteIgp7uRJ4tXfa+PZh MFvXj+llBUtio3udy6ME6fmE69OuNMQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-412-wh0zyP4bOgaH95Tsff0Ryw-1; Thu, 04 Mar 2021 12:21:58 -0500 X-MC-Unique: wh0zyP4bOgaH95Tsff0Ryw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BBC8E19057A1; Thu, 4 Mar 2021 17:21:56 +0000 (UTC) Received: from [10.36.113.171] (ovpn-113-171.ams2.redhat.com [10.36.113.171]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8D5D51002393; Thu, 4 Mar 2021 17:21:55 +0000 (UTC) Subject: Re: [PATCH] mm/hugetlb: suppress wrong warning info when alloc gigantic page To: Mike Kravetz , Chen Wandun , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20210219123909.13130-1-chenwandun@huawei.com> <46e76ac3-def1-80d4-14f1-61f7cd00d033@oracle.com> <2cb384b9-1301-59a8-f678-c67ee26053b3@oracle.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <17c958bc-d421-f48b-a07a-bf22afc32d33@redhat.com> Date: Thu, 4 Mar 2021 18:21:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <2cb384b9-1301-59a8-f678-c67ee26053b3@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04.03.21 18:20, Mike Kravetz wrote: > On 3/4/21 1:35 AM, David Hildenbrand wrote: >> On 19.02.21 20:14, Mike Kravetz wrote: >>> On 2/19/21 4:39 AM, Chen Wandun wrote: >>>> If hugetlb_cma is enabled, it will skip boot time allocation >>>> when allocating gigantic page, that doesn't means allocation >>>> failure, so suppress this warning info. >>>> >>> >>> Normally the addition of warning messages is discouraged. However, in >>> this case the additional message provides value. Why? >>> >>> Prior to the commit cf11e85fc08c, one could have a kernel command line >>> that contains: >>> >>> hugepagesz=1G hugepages=16 >>> >>> This would allocate 16 1G pages at boot time. >>> >>> After the commit, someone could specify a command line containing: >>> >>> hugepagesz=1G hugepages=16 hugetlb_cma=16G >>> >>> In this case, 16G of CMA will be reserved for 1G huge page allocations >>> after boot time. The parameter 'hugepages=16' is ignored, and the warning >>> message is logged. The warning message should only be logged when the >>> kernel parameter 'hugepages=' is ignored. >>> >>> IMO, it make sense to log a warning if ignoring a user specified parameter. >>> The user should not be attempting boot time allocation and CMA reservation >>> for 1G pages. >>> >>> I do not think we should drop the warning as the it tells the user thay >>> have specified two incompatible allocation options. >>> >> >> I agree. It has value. >> > > Hi David, > > Sorry my above reply was too quick as I did not take a close look at > the code/patch. See, > > https://lore.kernel.org/mm-commits/YDAbeDsG7GhV6s6B@carbon.dhcp.thefacebook.com/ > > This patch is actually in Andrew's tree. > Oh, I missed that discussion - thanks for the pointer! -- Thanks, David / dhildenb