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=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 3DE41C433FE for ; Wed, 9 Dec 2020 09:57:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AFE7123433 for ; Wed, 9 Dec 2020 09:57:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AFE7123433 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 282E06B00D2; Wed, 9 Dec 2020 04:57:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 20BA26B00D3; Wed, 9 Dec 2020 04:57:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0FE0D6B00D4; Wed, 9 Dec 2020 04:57:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0139.hostedemail.com [216.40.44.139]) by kanga.kvack.org (Postfix) with ESMTP id E7D546B00D2 for ; Wed, 9 Dec 2020 04:57:48 -0500 (EST) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B5A31FB46 for ; Wed, 9 Dec 2020 09:57:48 +0000 (UTC) X-FDA: 77573292216.25.boy62_5304db7273ee Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 92DC91804DF99 for ; Wed, 9 Dec 2020 09:57:48 +0000 (UTC) X-HE-Tag: boy62_5304db7273ee X-Filterd-Recvd-Size: 4267 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf02.hostedemail.com (Postfix) with ESMTP for ; Wed, 9 Dec 2020 09:57:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607507867; h=from:from: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=Dke/0tBf78HdlvQE9wUM0dJ9CCsXJgYBnBHm6bEO7Xo=; b=JC26BXRidZtBR0I2BqI2gvPqt8hYXRuwzQS7feiB8IgitAL7ozaFuZ7a9vzsDYIC5nq5z4 X6YIFWYqyUXRclAMJHkVgDxpLFfVA9unUtmgbvWiQedvkkFadzYOi3zgNsvU1HeNjHeJsO SbMXZwOaFLYsCZbPF/6sKUaCjMkTnsQ= 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-411-GMhEVBD9MRCd8njopXx6ag-1; Wed, 09 Dec 2020 04:57:45 -0500 X-MC-Unique: GMhEVBD9MRCd8njopXx6ag-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D24066D525; Wed, 9 Dec 2020 09:57:40 +0000 (UTC) Received: from [10.36.114.167] (ovpn-114-167.ams2.redhat.com [10.36.114.167]) by smtp.corp.redhat.com (Postfix) with ESMTP id 68CD96064B; Wed, 9 Dec 2020 09:57:34 +0000 (UTC) Subject: Re: [PATCH v7 06/15] mm/hugetlb: Disable freeing vmemmap if struct page size is not power of two To: Muchun Song , corbet@lwn.net, mike.kravetz@oracle.com, 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, willy@infradead.org, osalvador@suse.de, mhocko@suse.com, song.bao.hua@hisilicon.com Cc: duanxiongchun@bytedance.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org References: <20201130151838.11208-1-songmuchun@bytedance.com> <20201130151838.11208-7-songmuchun@bytedance.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Wed, 9 Dec 2020 10:57:33 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201130151838.11208-7-songmuchun@bytedance.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 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 30.11.20 16:18, Muchun Song wrote: > We only can free the tail vmemmap pages of HugeTLB to the buddy allocator > when the size of struct page is a power of two. > > Signed-off-by: Muchun Song > --- > mm/hugetlb_vmemmap.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c > index 51152e258f39..ad8fc61ea273 100644 > --- a/mm/hugetlb_vmemmap.c > +++ b/mm/hugetlb_vmemmap.c > @@ -111,6 +111,11 @@ void __init hugetlb_vmemmap_init(struct hstate *h) > unsigned int nr_pages = pages_per_huge_page(h); > unsigned int vmemmap_pages; > > + if (!is_power_of_2(sizeof(struct page))) { > + pr_info("disable freeing vmemmap pages for %s\n", h->name); I'd just drop that pr_info(). Users are able to observe that it's working (below), so they are able to identify that it's not working as well. > + return; > + } > + > vmemmap_pages = (nr_pages * sizeof(struct page)) >> PAGE_SHIFT; > /* > * The head page and the first tail page are not to be freed to buddy > Please squash this patch into the enabling patch and add a comment instead, like /* We cannot optimize if a "struct page" crosses page boundaries. */ -- Thanks, David / dhildenb