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=-3.8 required=3.0 tests=BAYES_00, 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 2F313C4167B for ; Thu, 10 Dec 2020 11:41:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBA6223D5A for ; Thu, 10 Dec 2020 11:41:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733234AbgLJLlG (ORCPT ); Thu, 10 Dec 2020 06:41:06 -0500 Received: from mx2.suse.de ([195.135.220.15]:38766 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728423AbgLJLlF (ORCPT ); Thu, 10 Dec 2020 06:41:05 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 913DCACC6; Thu, 10 Dec 2020 11:40:21 +0000 (UTC) Date: Thu, 10 Dec 2020 11:15:26 +0100 From: Oscar Salvador To: Muchun Song Cc: 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, mhocko@suse.com, song.bao.hua@hisilicon.com, david@redhat.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 v8 10/12] mm/hugetlb: Introduce nr_free_vmemmap_pages in the struct hstate Message-ID: <20201210101526.GA4525@localhost.localdomain> References: <20201210035526.38938-1-songmuchun@bytedance.com> <20201210035526.38938-11-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201210035526.38938-11-songmuchun@bytedance.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Dec 10, 2020 at 11:55:24AM +0800, Muchun Song wrote: > +void __init hugetlb_vmemmap_init(struct hstate *h) > +{ > + unsigned int nr_pages = pages_per_huge_page(h); > + unsigned int vmemmap_pages; > + > + /* We cannot optimize if a "struct page" crosses page boundaries. */ > + if (!is_power_of_2(sizeof(struct page))) > + return; > + > + if (!hugetlb_free_vmemmap_enabled) > + return; I think it would make sense to squash the last patch and this one. As per the last patch, if "struct page" is not power of 2, early_hugetlb_free_vmemmap_param() does not set hugetlb_free_vmemmap_enabled, so the "!is_power_of_2" check from above would become useless here. We know that in order for hugetlb_free_vmemmap_enabled to become true, the is_power_of_2 must have succeed early on when calling the early_ function. -- Oscar Salvador SUSE L3