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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 91D0AC49ED7 for ; Thu, 19 Sep 2019 14:23:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6C98520882 for ; Thu, 19 Sep 2019 14:23:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390604AbfISOXt (ORCPT ); Thu, 19 Sep 2019 10:23:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34090 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403873AbfISOXo (ORCPT ); Thu, 19 Sep 2019 10:23:44 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 50D97E2520; Thu, 19 Sep 2019 14:23:44 +0000 (UTC) Received: from t460s.redhat.com (unknown [10.36.118.9]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5D15A60606; Thu, 19 Sep 2019 14:23:39 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtualization@lists.linux-foundation.org, Andrea Arcangeli , David Hildenbrand , "Michael S. Tsirkin" , Jason Wang , Oscar Salvador , Michal Hocko , Igor Mammedov , Dave Young , Andrew Morton , Dan Williams , Pavel Tatashin , Stefan Hajnoczi , Vlastimil Babka Subject: [PATCH RFC v3 9/9] virtio-mem: Offline and remove completely unplugged memory blocks Date: Thu, 19 Sep 2019 16:22:28 +0200 Message-Id: <20190919142228.5483-10-david@redhat.com> In-Reply-To: <20190919142228.5483-1-david@redhat.com> References: <20190919142228.5483-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Thu, 19 Sep 2019 14:23:44 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Let's offline+remove memory blocks once all subblocks are unplugged. We can use the new Linux MM interface for that. As no memory is in use anymore, this shouldn't take a long time and shouldn't fail. There might be corner cases where the offlining could still fail (especially, if another notifier NACKs the offlining request). Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Oscar Salvador Cc: Michal Hocko Cc: Igor Mammedov Cc: Dave Young Cc: Andrew Morton Cc: Dan Williams Cc: Pavel Tatashin Cc: Stefan Hajnoczi Cc: Vlastimil Babka Signed-off-by: David Hildenbrand --- drivers/virtio/virtio_mem.c | 39 ++++++++++++++++++++++++++++++++++--- 1 file changed, 36 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index 9cb31459b211..01d5fc784d5d 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -433,6 +433,28 @@ static int virtio_mem_mb_remove(struct virtio_mem *vm, unsigned long mb_id) return remove_memory(nid, addr, memory_block_size_bytes()); } +/* + * Try to offline and remove a memory block from Linux. + * + * Must not be called with the vm->hotplug_mutex held (possible deadlock with + * onlining code). + * + * Will not modify the state of the memory block. + */ +static int virtio_mem_mb_offline_and_remove(struct virtio_mem *vm, + unsigned long mb_id) +{ + const uint64_t addr = virtio_mem_mb_id_to_phys(mb_id); + int nid = vm->nid; + + if (nid == NUMA_NO_NODE) + nid = memory_add_physaddr_to_nid(addr); + + dev_dbg(&vm->vdev->dev, "offlining and removing memory block: %lu\n", + mb_id); + return offline_and_remove_memory(nid, addr, memory_block_size_bytes()); +} + /* * Trigger the workqueue so the device can perform its magic. */ @@ -1263,7 +1285,8 @@ static int virtio_mem_mb_unplug_any_sb_offline(struct virtio_mem *vm, * Unplug the desired number of plugged subblocks of an online memory block. * Will skip subblock that are busy. * - * Will modify the state of the memory block. + * Will modify the state of the memory block. Might temporarily drop the + * hotplug_mutex. * * Note: Can fail after some subblocks were successfully unplugged. Can * return 0 even if subblocks were busy and could not get unplugged. @@ -1319,9 +1342,19 @@ static int virtio_mem_mb_unplug_any_sb_online(struct virtio_mem *vm, } /* - * TODO: Once all subblocks of a memory block were unplugged, we want - * to offline the memory block and remove it. + * Once all subblocks of a memory block were unplugged, offline and + * remove it. This will usually not fail, as no memory is in use + * anymore - however some other notifiers might NACK the request. */ + if (virtio_mem_mb_test_sb_unplugged(vm, mb_id, 0, vm->nb_sb_per_mb)) { + mutex_unlock(&vm->hotplug_mutex); + rc = virtio_mem_mb_offline_and_remove(vm, mb_id); + mutex_lock(&vm->hotplug_mutex); + if (!rc) + virtio_mem_mb_set_state(vm, mb_id, + VIRTIO_MEM_MB_STATE_UNUSED); + } + return 0; } -- 2.21.0