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=-9.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 71A3BC43457 for ; Mon, 12 Oct 2020 12:55:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A8A921D7F for ; Mon, 12 Oct 2020 12:55:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MiL6EpsX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730166AbgJLMzk (ORCPT ); Mon, 12 Oct 2020 08:55:40 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:31456 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726495AbgJLMzj (ORCPT ); Mon, 12 Oct 2020 08:55:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602507338; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6CxxBkFaIBujR5H4ePNpLjJNj4n9V2qfQRlFDh40t9U=; b=MiL6EpsXLcVJ20gYAtC0fGcKTOv2W/cwcE/lX8LEcoZys3G3TD34Hw7QRd5cFd3DXaQTZ4 RqymOQfhao/C75ZFev9jw9e576VoHt9j6HwCHEfUgSxk41nSYF3XU9RMHU1TbdnuIOJDML qad+miiD/bGsjRvwKtJ1rB8eKXnP3fo= 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-12-GRLVSriTMdWbbPBGQs18-g-1; Mon, 12 Oct 2020 08:55:35 -0400 X-MC-Unique: GRLVSriTMdWbbPBGQs18-g-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D85041084D63; Mon, 12 Oct 2020 12:55:33 +0000 (UTC) Received: from t480s.redhat.com (ovpn-113-251.ams2.redhat.com [10.36.113.251]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8580D60C07; Mon, 12 Oct 2020 12:55:20 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtualization@lists.linux-foundation.org, Andrew Morton , "Michael S . Tsirkin" , David Hildenbrand , Jason Wang , Pankaj Gupta Subject: [PATCH v1 15/29] virito-mem: document Sub Block Mode (SBM) Date: Mon, 12 Oct 2020 14:53:09 +0200 Message-Id: <20201012125323.17509-16-david@redhat.com> In-Reply-To: <20201012125323.17509-1-david@redhat.com> References: <20201012125323.17509-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Let's add some documentation for the current mode - Sub Block Mode (SBM) - to prepare for a new mode - Big Block Mode (BBM). Follow-up patches will properly factor out the existing Sub Block Mode (SBM) and implement Device Block Mode (DBM). Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Pankaj Gupta Signed-off-by: David Hildenbrand --- drivers/virtio/virtio_mem.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index faeb759687fe..fd8685673fe4 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -27,6 +27,21 @@ static bool unplug_online = true; module_param(unplug_online, bool, 0644); MODULE_PARM_DESC(unplug_online, "Try to unplug online memory"); +/* + * virtio-mem currently supports the following modes of operation: + * + * * Sub Block Mode (SBM): A Linux memory block spans 1..X subblocks (SB). The + * size of a Sub Block (SB) is determined based on the device block size, the + * pageblock size, and the maximum allocation granularity of the buddy. + * Subblocks within a Linux memory block might either be plugged or unplugged. + * Memory is added/removed to Linux MM in Linux memory block granularity. + * + * User space / core MM (auto onlining) is responsible for onlining added + * Linux memory blocks - and for selecting a zone. Linux Memory Blocks are + * always onlined separately, and all memory within a Linux memory block is + * onlined to the same zone - virtio-mem relies on this behavior. + */ + enum virtio_mem_mb_state { /* Unplugged, not added to Linux. Can be reused later. */ VIRTIO_MEM_MB_STATE_UNUSED = 0, -- 2.26.2