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=-7.5 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 33562C433DB for ; Mon, 25 Jan 2021 11:23:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7C3CE22795 for ; Mon, 25 Jan 2021 11:23:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C3CE22795 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 C98C08D0002; Mon, 25 Jan 2021 06:23:21 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C4B488D0001; Mon, 25 Jan 2021 06:23:21 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B616D8D0002; Mon, 25 Jan 2021 06:23:21 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0147.hostedemail.com [216.40.44.147]) by kanga.kvack.org (Postfix) with ESMTP id A35678D0001 for ; Mon, 25 Jan 2021 06:23:21 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 6173E181AEF3F for ; Mon, 25 Jan 2021 11:23:21 +0000 (UTC) X-FDA: 77744061402.02.oven18_3101de427585 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id 2C8BD10097AA0 for ; Mon, 25 Jan 2021 11:23:21 +0000 (UTC) X-HE-Tag: oven18_3101de427585 X-Filterd-Recvd-Size: 3864 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by imf02.hostedemail.com (Postfix) with ESMTP for ; Mon, 25 Jan 2021 11:23:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611573800; 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=RUR1kdiVhM2we5zSsKmR+IJNxPESBP8a30L7UKGsPr4=; b=Bg3ZJv2bk+exCQ4FbXIz6yV3hvkV1sf8TCA/IWXjqwkqZ3OZW0jGdEDHQDruufk5AyIZHR 42z8Ps66NwOE8E9R0MKivoZbcQPT9h/295yvh3qrny3YNaReln7Le5IZT9y8vc/Dd+LqB6 Rq93n+G5ME6oNwR2BxyRFzFfoE1vECw= 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-178-uqtLs3PgNEy80gLVFtO7Sw-1; Mon, 25 Jan 2021 06:23:17 -0500 X-MC-Unique: uqtLs3PgNEy80gLVFtO7Sw-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 851C41005513; Mon, 25 Jan 2021 11:23:15 +0000 (UTC) Received: from [10.36.115.13] (ovpn-115-13.ams2.redhat.com [10.36.115.13]) by smtp.corp.redhat.com (Postfix) with ESMTP id D2611722C1; Mon, 25 Jan 2021 11:23:13 +0000 (UTC) Subject: Re: [PATCH 2/5] mm,memory_hotplug: Allocate memmap from the added memory range To: Oscar Salvador Cc: Anshuman Khandual , akpm@linux-foundation.org, mhocko@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, vbabka@suse.cz, pasha.tatashin@soleen.com References: <20201217130758.11565-1-osalvador@suse.de> <20201217130758.11565-3-osalvador@suse.de> <21079c2d-67d0-fc59-8d7f-0795b3f8a3e3@redhat.com> <20210125103951.GA27851@linux> <20210125111816.GB28363@linux> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Mon, 25 Jan 2021 12:23:12 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20210125111816.GB28363@linux> 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 25.01.21 12:18, Oscar Salvador wrote: > On Mon, Jan 25, 2021 at 11:57:20AM +0100, David Hildenbrand wrote: >> I'm confused. >> >> 1. Assume we hotplug memory, online it to ZONE_MOVABLE. The vmemmap gets >> allocated from altmap space. > > The vmemmap could have never been allocated from altmap in case hpage vmemmap > feature is enabled. > > Have a look at [1]. > If is_hugetlb_free_vmemmap_enabled(), vmemmap_populate() ends up calling > vmemmap_populate_basepages(). Oh, it calls "vmemmap_populate_basepages(start, end, node, NULL);" the "NULL" part is the important bit. > > And since no memory was consumed from altmap, and hence altmap_alloc_block_buf() > was never called, vmem_altmap->alloc will be 0, and memory_block->nr_vmemmap_pages > will be 0 as well. > > But on a second though, true is that we will get in trouble if hpage vmemmap > feature ever gets to work with vmemmap_populate_hugepages. > I will queue that to look in a new future. This seriously needs comments and documentation. The problem is where to document as long as one of both series is not merged yet :) At least in the cover letter, because this is not obvious how both things will play along. Thanks! -- Thanks, David / dhildenb