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,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 B4569C433E0 for ; Tue, 26 Jan 2021 20:14:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A3DA22241 for ; Tue, 26 Jan 2021 20:14:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732574AbhAZFYd (ORCPT ); Tue, 26 Jan 2021 00:24:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727987AbhAYMkh (ORCPT ); Mon, 25 Jan 2021 07:40:37 -0500 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5557C0617A7 for ; Mon, 25 Jan 2021 04:32:08 -0800 (PST) Received: by mail-pg1-x530.google.com with SMTP id t25so850043pga.2 for ; Mon, 25 Jan 2021 04:32:08 -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=ECcZXTiq168nlNhR7ZlqDDfbZIIxsXgGrmSQrRFKW1k=; b=Ph4WYGn2BsoGsFlVUnxP3hj1VCYxYacseAW5OCLeblJYeuG6yu8s2kOfPKEe1xrBHP Kvmuq9KxZ2+muLC0d/R5BiHA2WC5v0Hv85KR6xMMw1JqzIxHpZPr1qPOO3HsD7aSUO0T BmjzqkDTnMkNb47FKaRVXulU2QoYBXcFFYeLrtVufuq3/10W2RtYZftnMiSDr+up8FOo RtVIBdv1rcBVrDMYWzRMFR5jn8g/XDdBEQ94kEIlQsf1K9d0Hs3Ge+yhC/YnCm0w5RM6 mNhCqldAM5m+kJLkSCaadYu4ZaczmwJS3OwlJ917t55v5AkhUyPwGOMyk8eO+44Z4bBZ LkXw== 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=ECcZXTiq168nlNhR7ZlqDDfbZIIxsXgGrmSQrRFKW1k=; b=RrOE9/PaujauiDmvykZ8kvB9Yl91hazv3iyT/c1utu2lNzgll5VqunJ1DAc49vY6g1 9zW/+u2KNO8d960fqBl82+WLuWlEFIg9EEvOkpjDGw8vIv8fvul34gl89XLxNjYqnu9V /HIEqMAVYd1PVUUlokvRdThSs1jVIDO05qaB2uuOYfE2pO55sQKs1MPbwr9tAl+qOv6F BIhO4wxRz/o2raC8XY6jRxQcTLMm3O6tILOTO7K0xQwueoYmlWXoKnZwlP5/BC/lV35u msJhT7SrU4joP/w6mnKF4aYAKG1MxS+IHb8TrAUApZ82zAIx60k0SdsGmQgWi6bJzyQU sZHw== X-Gm-Message-State: AOAM5309gptPOEKpUUe2GuxUcK+UkQIFi4X147D9pKErWGAj2AHHgMoF wen0/Dp+YNZdkxqXcOvPq2Vx+mODXf9muqiN0eDzDA== X-Google-Smtp-Source: ABdhPJxv7O9hvhAigWaoL82tnMBoDZgg+H4lyx4pRubFGd/QUUt0UnNO1EEo+PnyWnmbi+w8Cm1zJisMoarJUFLjK7E= X-Received: by 2002:a63:1f21:: with SMTP id f33mr419885pgf.31.1611577928305; Mon, 25 Jan 2021 04:32:08 -0800 (PST) MIME-Version: 1.0 References: <20210117151053.24600-1-songmuchun@bytedance.com> <20210117151053.24600-10-songmuchun@bytedance.com> <7550ebba-fdb5-0dc9-a517-dda56bd105d9@redhat.com> <20210125120827.GA29289@linux> In-Reply-To: <20210125120827.GA29289@linux> From: Muchun Song Date: Mon, 25 Jan 2021 20:31:31 +0800 Message-ID: Subject: Re: [External] Re: [PATCH v13 09/12] mm: hugetlb: add a kernel parameter hugetlb_free_vmemmap To: Oscar Salvador Cc: David Hildenbrand , 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 , Michal Hocko , "Song Bao Hua (Barry Song)" , =?UTF-8?B?SE9SSUdVQ0hJIE5BT1lBKOWggOWPoyDnm7TkuZ8p?= , 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-fsdevel@vger.kernel.org On Mon, Jan 25, 2021 at 8:08 PM Oscar Salvador wrote: > > On Mon, Jan 25, 2021 at 12:43:23PM +0100, David Hildenbrand wrote: > > > - if (end - start < PAGES_PER_SECTION * sizeof(struct page)) > > > + if (is_hugetlb_free_vmemmap_enabled() || > > > + end - start < PAGES_PER_SECTION * sizeof(struct page)) > > > > This looks irresponsible. You ignore any altmap, even though current > > altmap users (ZONE_DEVICE) will not actually result in applicable > > vmemmaps that huge pages could ever use. > > > > Why do you ignore the altmap completely? This has to be properly > > documented, but IMHO it's not even the right approach to mess with > > altmap here. > > The goal was not to ignore altmap but to disable PMD mapping sections > when the feature was enabled. > Shame on me I did not notice that with this, altmap will be ignored. > > Something like below maybe: Yeah, Thanks a lot. > > int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, > struct vmem_altmap *altmap) > { > int err; > bool populate_base_pages = false; > > if ((end - start < PAGES_PER_SECTION * sizeof(struct page)) || > (is_hugetlb_free_vmemmap_enabled() && !altmap)) > populate_base_pages = true; > > if (populate_base_pages) { > err = vmemmap_populate_basepages(start, end, node, NULL); > } else if (boot_cpu_has(X86_FEATURE_PSE)) { > .... > > > > > > -- > > Thanks, > > > > David / dhildenb > > > > > > -- > Oscar Salvador > SUSE L3