From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-6506-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 56383985DD7 for ; Thu, 12 Dec 2019 17:13:14 +0000 (UTC) From: David Hildenbrand Date: Thu, 12 Dec 2019 18:11:33 +0100 Message-Id: <20191212171137.13872-10-david@redhat.com> In-Reply-To: <20191212171137.13872-1-david@redhat.com> References: <20191212171137.13872-1-david@redhat.com> MIME-Version: 1.0 Subject: [virtio-dev] [PATCH RFC v4 09/13] virtio-mem: Offline and remove completely unplugged memory blocks Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko , Andrew Morton , "Michael S . Tsirkin" , David Hildenbrand , Jason Wang , Oscar Salvador , Igor Mammedov , Dave Young , Dan Williams , Pavel Tatashin , Stefan Hajnoczi , Vlastimil Babka List-ID: 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 | 47 +++++++++++++++++++++++++++++++++---- 1 file changed, 43 insertions(+), 4 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index a12a0f9c076b..807d4e393427 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -436,6 +436,28 @@ static int virtio_mem_mb_remove(struct virtio_mem *vm,= unsigned long mb_id) =09return remove_memory(nid, addr, memory_block_size_bytes()); } =20 +/* + * Try to offline and remove a memory block from Linux. + * + * Must not be called with the vm->hotplug_mutex held (possible deadlock w= ith + * onlining code). + * + * Will not modify the state of the memory block. + */ +static int virtio_mem_mb_offline_and_remove(struct virtio_mem *vm, +=09=09=09=09=09 unsigned long mb_id) +{ +=09const uint64_t addr =3D virtio_mem_mb_id_to_phys(mb_id); +=09int nid =3D vm->nid; + +=09if (nid =3D=3D NUMA_NO_NODE) +=09=09nid =3D memory_add_physaddr_to_nid(addr); + +=09dev_dbg(&vm->vdev->dev, "offlining and removing memory block: %lu\n", +=09=09mb_id); +=09return offline_and_remove_memory(nid, addr, memory_block_size_bytes()); +} + /* * Trigger the workqueue so the device can perform its magic. */ @@ -529,7 +551,13 @@ static void virtio_mem_notify_offline(struct virtio_me= m *vm, =09=09break; =09} =20 -=09/* trigger the workqueue, maybe we can now unplug memory. */ +=09/* +=09 * Trigger the workqueue, maybe we can now unplug memory. Also, +=09 * when we offline and remove a memory block, this will re-trigger +=09 * us immediately - which is often nice because the removal of +=09 * the memory block (e.g., memmap) might have freed up memory +=09 * on other memory blocks we manage. +=09 */ =09virtio_mem_retry(vm); } =20 @@ -1275,7 +1303,8 @@ static int virtio_mem_mb_unplug_any_sb_offline(struct= virtio_mem *vm, * Unplug the desired number of plugged subblocks of an online memory bloc= k. * 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. @@ -1331,9 +1360,19 @@ static int virtio_mem_mb_unplug_any_sb_online(struct= virtio_mem *vm, =09} =20 =09/* -=09 * TODO: Once all subblocks of a memory block were unplugged, we want -=09 * to offline the memory block and remove it. +=09 * Once all subblocks of a memory block were unplugged, offline and +=09 * remove it. This will usually not fail, as no memory is in use +=09 * anymore - however some other notifiers might NACK the request. =09 */ +=09if (virtio_mem_mb_test_sb_unplugged(vm, mb_id, 0, vm->nb_sb_per_mb)) { +=09=09mutex_unlock(&vm->hotplug_mutex); +=09=09rc =3D virtio_mem_mb_offline_and_remove(vm, mb_id); +=09=09mutex_lock(&vm->hotplug_mutex); +=09=09if (!rc) +=09=09=09virtio_mem_mb_set_state(vm, mb_id, +=09=09=09=09=09=09VIRTIO_MEM_MB_STATE_UNUSED); +=09} + =09return 0; } =20 --=20 2.23.0 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org