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=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 791A3C4361B for ; Wed, 9 Dec 2020 10:04:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2146523444 for ; Wed, 9 Dec 2020 10:04:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729669AbgLIKEU (ORCPT ); Wed, 9 Dec 2020 05:04:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729095AbgLIKEU (ORCPT ); Wed, 9 Dec 2020 05:04:20 -0500 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEFCAC061793 for ; Wed, 9 Dec 2020 02:03:39 -0800 (PST) Received: by mail-pl1-x643.google.com with SMTP id t18so681716plo.0 for ; Wed, 09 Dec 2020 02:03:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=L4gIWYaJaNZduh4JA7eIlOxCXtQORUEEZY9m5DkEeWg=; b=l9npCqtiWi6nm8WXc9Qci3HNqajeaFHfw3ao8fKDtkmuOfyiKaVSaitH/E/JRbjrv4 0n8xsbdnhhNokdQjHGXGu0H2xPThEITAaW8TfUEeSBwjn/7s4evUip6C2wAgVLLtQOFg L9v1HvMHHIK16p7/ePp2Zmv8Uc6RmNXdkslycCkxclPEBFF2DESf8spil2nEvkQ+FLBZ tNGk8NMaxD/LOlx381vwi9mrf07041UpOHZFzOY82UlsVLDMJGGjJNoOkZ9Do1Asz4qp r/h0GnWLRyTMvuaqqWZtPFKTZB++54sOygrU2zP6ESM4PVaCFZOuk+DFxp65rH7FZXSL AvRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=L4gIWYaJaNZduh4JA7eIlOxCXtQORUEEZY9m5DkEeWg=; b=kcnQeP/dQ/ozR78tYbOyRJBT/mo0HmPkRkfYOAoU70C6l/wxzCE6wRfM2l7bA0AhW6 m0QwMv+0NIiXEFM8kln1v6fM3qn2Aa/OFEv6weD+a7qOd6/Fp/jBkR3SSj5cmyAh7epp 2NAeWoi195J2rMNOhVPPbr/daXEzKmx8t73P4L8NJ/KIGBTjY33wv4Lhu55zzgC/+4SX JCmIyuRLZnaqxgn2IhjRArKV00adKuw/wLSP9hXeSLoP+lAgLNLthXcTooucx464EHiV p9BeV6NAsWTtsLHBDvaqfzXj9O1Q3+6CyvF8TDFJ0gEhLGeh+7tbiBi0HiKvW3T45UZi Lyng== X-Gm-Message-State: AOAM533GLH926pb64kpLp19XEeWmemRkomW3Rcy86c1ZtGosJOefPYnE AapPvYmnwNSi6cgisrKIx0LwB9nqXxH2ILh8yIG0kw== X-Google-Smtp-Source: ABdhPJwLeHxukD6MEvUiceVVZUfrPocdn+tRQUO6LQUONC5Tz16TBKz/PD0oEJKhT4wgjGrX/3qsMLMUQcocS3f1/hc= X-Received: by 2002:a17:902:76c8:b029:d9:d6c3:357d with SMTP id j8-20020a17090276c8b02900d9d6c3357dmr1336707plt.34.1607508219309; Wed, 09 Dec 2020 02:03:39 -0800 (PST) MIME-Version: 1.0 References: <20201130151838.11208-1-songmuchun@bytedance.com> <20201130151838.11208-7-songmuchun@bytedance.com> In-Reply-To: From: Muchun Song Date: Wed, 9 Dec 2020 18:03:02 +0800 Message-ID: Subject: Re: [External] Re: [PATCH v7 06/15] mm/hugetlb: Disable freeing vmemmap if struct page size is not power of two To: David Hildenbrand Cc: Jonathan Corbet , Mike Kravetz , Thomas Gleixner , mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, Peter Zijlstra , viro@zeniv.linux.org.uk, Andrew Morton , paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, Randy Dunlap , oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, Mina Almasry , David Rientjes , Matthew Wilcox , Oscar Salvador , Michal Hocko , "Song Bao Hua (Barry Song)" , Xiongchun duan , linux-doc@vger.kernel.org, LKML , Linux Memory Management List , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 9, 2020 at 5:57 PM David Hildenbrand wrote: > > 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. The below is just a pr_debug. Do you suggest converting it to pr_info? > > > + 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. */ > Will do. Thanks. > -- > Thanks, > > David / dhildenb > -- Yours, Muchun