From: David Hildenbrand <david@redhat.com>
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 <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Michael S . Tsirkin" <mst@redhat.com>,
David Hildenbrand <david@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Oscar Salvador <osalvador@suse.de>,
Igor Mammedov <imammedo@redhat.com>,
Dave Young <dyoung@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: [PATCH v2 08/10] virtio-mem: Offline and remove completely unplugged memory blocks
Date: Wed, 11 Mar 2020 18:14:20 +0100 [thread overview]
Message-ID: <20200311171422.10484-9-david@redhat.com> (raw)
In-Reply-To: <20200311171422.10484-1-david@redhat.com>
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" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
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 35f20232770c..aa322e7732a4 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -443,6 +443,28 @@ 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.
*/
@@ -535,7 +557,13 @@ static void virtio_mem_notify_offline(struct virtio_mem *vm,
break;
}
- /* trigger the workqueue, maybe we can now unplug memory. */
+ /*
+ * Trigger the workqueue, maybe we can now unplug memory. Also,
+ * when we offline and remove a memory block, this will re-trigger
+ * us immediately - which is often nice because the removal of
+ * the memory block (e.g., memmap) might have freed up memory
+ * on other memory blocks we manage.
+ */
virtio_mem_retry(vm);
}
@@ -1282,7 +1310,8 @@ 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.
@@ -1338,9 +1367,19 @@ 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;
}
--
2.24.1
next prev parent reply other threads:[~2020-03-11 17:16 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-11 17:14 [PATCH v2 00/10] virtio-mem: paravirtualized memory David Hildenbrand
2020-03-11 17:14 ` [PATCH v2 01/10] virtio-mem: Paravirtualized memory hotplug David Hildenbrand
2020-04-15 5:59 ` Pankaj Gupta
2020-03-11 17:14 ` [PATCH v2 02/10] virtio-mem: Allow to specify an ACPI PXM as nid David Hildenbrand
2020-03-30 11:04 ` Pankaj Gupta
2020-03-11 17:14 ` [PATCH v2 03/10] virtio-mem: Paravirtualized memory hotunplug part 1 David Hildenbrand
2020-03-11 17:14 ` [PATCH v2 04/10] virtio-mem: Paravirtualized memory hotunplug part 2 David Hildenbrand
2020-03-11 17:14 ` [PATCH v2 05/10] mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE David Hildenbrand
2020-04-14 16:34 ` Michael S. Tsirkin
2020-04-15 0:32 ` Andrew Morton
2020-03-11 17:14 ` [PATCH v2 06/10] virtio-mem: Allow to offline partially unplugged memory blocks David Hildenbrand
2020-03-11 17:14 ` [PATCH v2 07/10] mm/memory_hotplug: Introduce offline_and_remove_memory() David Hildenbrand
2020-03-11 17:19 ` David Hildenbrand
2020-04-14 16:35 ` Michael S. Tsirkin
2020-04-15 0:30 ` Andrew Morton
2020-04-15 7:35 ` Pankaj Gupta
2020-03-11 17:14 ` David Hildenbrand [this message]
2020-04-15 7:42 ` [PATCH v2 08/10] virtio-mem: Offline and remove completely unplugged memory blocks Pankaj Gupta
2020-03-11 17:14 ` [PATCH v2 09/10] virtio-mem: Better retry handling David Hildenbrand
2020-03-11 17:14 ` [PATCH v2 10/10] MAINTAINERS: Add myself as virtio-mem maintainer David Hildenbrand
2020-03-27 16:58 ` [PATCH v2 00/10] virtio-mem: paravirtualized memory Pankaj Gupta
2020-03-27 17:03 ` David Hildenbrand
2020-03-27 17:07 ` David Hildenbrand
2020-03-29 15:41 ` Pankaj Gupta
2020-03-30 8:42 ` David Hildenbrand
2020-03-29 12:42 ` Michael S. Tsirkin
2020-03-30 8:16 ` David Hildenbrand
2020-04-14 9:15 ` David Hildenbrand
2020-04-14 16:28 ` Michael S. Tsirkin
2020-04-14 18:39 ` David Hildenbrand
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