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=-7.3 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 76126C64E69 for ; Fri, 20 Nov 2020 09:31:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F97E22226 for ; Fri, 20 Nov 2020 09:31:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XhGLEFw5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727669AbgKTJbR (ORCPT ); Fri, 20 Nov 2020 04:31:17 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44868 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727646AbgKTJbM (ORCPT ); Fri, 20 Nov 2020 04:31:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605864671; 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=6aBIYZe6QvsR3R+sgcDGxOKiaDPY1p+gBWyXVlapmTM=; b=XhGLEFw5MXcPbaiNnsbxJC3qVhayRgjkUN6ZQmn9dEl3bluVfo01q2o7alUYTbRv15we9I /Hv73L+/ko0BL/qY1aupSk6bye1QlYjLFggL5h3RFGJ4J6KrgWD5S46/wONU7E8b2WS6t+ 5acoCO2IxeszyRfIQyzUnzrs3HI9+qE= 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-579-fkKSvjRaPlGNpOkGzmTmJg-1; Fri, 20 Nov 2020 04:31:08 -0500 X-MC-Unique: fkKSvjRaPlGNpOkGzmTmJg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8853D8144E1; Fri, 20 Nov 2020 09:31:07 +0000 (UTC) Received: from [10.36.114.78] (ovpn-114-78.ams2.redhat.com [10.36.114.78]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5993460854; Fri, 20 Nov 2020 09:31:06 +0000 (UTC) Subject: Re: [RFC PATCH 3/3] mm,memory_hotplug: Allocate memmap from the added memory range To: Oscar Salvador Cc: mhocko@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, vbabka@suse.cz, pasha.tatashin@soleen.com References: <20201022125835.26396-1-osalvador@suse.de> <20201022125835.26396-4-osalvador@suse.de> <3cc37927-538e-ae7d-27bc-45aaabe06b3a@redhat.com> <20201119104847.GA5281@localhost.localdomain> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Fri, 20 Nov 2020 10:31:05 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20201119104847.GA5281@localhost.localdomain> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> - move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE); >>> + move_pfn_range_to_zone(zone, pfn, nr_pages, nr_vmemmap_pages, NULL, >>> + MIGRATE_ISOLATE); >> >> As mentioned, I'd suggest properly initializing the memmap here >> >> if (nr_vmemmap_pages) { >> move_pfn_range_to_zone(zone, pfn, nr_vmemmap_pages, NULL, >> MIGRATE_UNMOVABLE); >> } >> move_pfn_range_to_zone(zone, valid_start_pfn, valid_nr_pages, NULL, > > Sure, agreed. > >>> + if (!support_memmap_on_memory(size)) >>> + mhp_flags &= ~MEMHP_MEMMAP_ON_MEMORY; >> >> Callers (e.g., virtio-mem) might rely on this. We should reject this with >> -EINVAL and provide a way for callers to test whether this flag is possible. > > Uhm, we might want to make "support_memmap_on_memory" public, and > callers who might want to it use can check its return value? > Or do you have something else in mind? Right, a way for callers to check if it's supported. "mhp_supports_memmap_on_memory" or sth. like that. Thanks! -- Thanks, David / dhildenb