diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index d6dde7d2cf76..4c1e14615001 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -85,6 +85,7 @@ config VIRTIO_MEM
 	depends on VIRTIO
 	depends on MEMORY_HOTPLUG_SPARSE
 	depends on MEMORY_HOTREMOVE
+	select CONTIG_ALLOC
 	help
 	 This driver provides access to virtio-mem paravirtualized memory
 	 devices, allowing to hotplug and hotunplug memory.
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index a3ec795be8be..74f0d3cb1d22 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -23,6 +23,10 @@
 
 #include <acpi/acpi_numa.h>
 
+static bool unplug_online = true;
+module_param(unplug_online, bool, 0644);
+MODULE_PARM_DESC(unplug_online, "Try to unplug online memory");
+
 enum virtio_mem_mb_state {
 	/* Unplugged, not added to Linux. Can be reused later. */
 	VIRTIO_MEM_MB_STATE_UNUSED = 0,
@@ -654,23 +658,35 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb,
 }
 
 /*
- * Set a range of pages PG_offline.
+ * Set a range of pages PG_offline. Remember pages that were never onlined
+ * (via generic_online_page()) using PageDirty().
  */
 static void virtio_mem_set_fake_offline(unsigned long pfn,
-					unsigned int nr_pages)
+					unsigned int nr_pages, bool onlined)
 {
-	for (; nr_pages--; pfn++)
-		__SetPageOffline(pfn_to_page(pfn));
+	for (; nr_pages--; pfn++) {
+		struct page *page = pfn_to_page(pfn);
+
+		__SetPageOffline(page);
+		if (!onlined)
+			SetPageDirty(page);
+	}
 }
 
 /*
- * Clear PG_offline from a range of pages.
+ * Clear PG_offline from a range of pages. If the pages were never onlined,
+ * (via generic_online_page()), clear PageDirty().
  */
 static void virtio_mem_clear_fake_offline(unsigned long pfn,
-					  unsigned int nr_pages)
+					  unsigned int nr_pages, bool onlined)
 {
-	for (; nr_pages--; pfn++)
-		__ClearPageOffline(pfn_to_page(pfn));
+	for (; nr_pages--; pfn++) {
+		struct page *page = pfn_to_page(pfn);
+
+		__ClearPageOffline(page);
+		if (!onlined)
+			ClearPageDirty(page);
+	}
 }
 
 /*
@@ -686,10 +702,26 @@ static void virtio_mem_fake_online(unsigned long pfn, unsigned int nr_pages)
 	 * We are always called with subblock granularity, which is at least
 	 * aligned to MAX_ORDER - 1.
 	 */
-	virtio_mem_clear_fake_offline(pfn, nr_pages);
+	for (i = 0; i < nr_pages; i += 1 << order) {
+		struct page *page = pfn_to_page(pfn + i);
 
-	for (i = 0; i < nr_pages; i += 1 << order)
-		generic_online_page(pfn_to_page(pfn + i), order);
+		/*
+		 * If the page is PageDirty(), it was kept fake-offline when
+		 * onlining the memory block. Otherwise, it was allocated
+		 * using alloc_contig_range(). All pages in a subblock are
+		 * alike.
+		 */
+		if (PageDirty(page)) {
+			virtio_mem_clear_fake_offline(pfn + i, 1 << order,
+						      false);
+			generic_online_page(page, order);
+		} else {
+			virtio_mem_clear_fake_offline(pfn + i, 1 << order,
+						      true);
+			free_contig_range(pfn + i, 1 << order);
+			adjust_managed_page_count(page, 1 << order);
+		}
+	}
 }
 
 static void virtio_mem_online_page_cb(struct page *page, unsigned int order)
@@ -718,7 +750,8 @@ static void virtio_mem_online_page_cb(struct page *page, unsigned int order)
 		if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
 			generic_online_page(page, order);
 		else
-			virtio_mem_set_fake_offline(PFN_DOWN(addr), 1 << order);
+			virtio_mem_set_fake_offline(PFN_DOWN(addr), 1 << order,
+						    false);
 		rcu_read_unlock();
 		return;
 	}
@@ -1186,6 +1219,72 @@ static int virtio_mem_mb_unplug_any_sb_offline(struct virtio_mem *vm,
 	return 0;
 }
 
+/*
+ * 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.
+ *
+ * Note: Can fail after some subblocks were successfully unplugged. Can
+ *       return 0 even if subblocks were busy and could not get unplugged.
+ */
+static int virtio_mem_mb_unplug_any_sb_online(struct virtio_mem *vm,
+					      unsigned long mb_id,
+					      uint64_t *nb_sb)
+{
+	const unsigned long nr_pages = PFN_DOWN(vm->subblock_size);
+	unsigned long start_pfn;
+	int rc, sb_id;
+
+	/*
+	 * TODO: To increase the performance we want to try bigger, consecutive
+	 * subblocks first before falling back to single subblocks. Also,
+	 * we should sense via something like is_mem_section_removable()
+	 * first if it makes sense to go ahead any try to allocate.
+	 */
+	for (sb_id = 0; sb_id < vm->nb_sb_per_mb && *nb_sb; sb_id++) {
+		/* Find the next candidate subblock */
+		while (sb_id < vm->nb_sb_per_mb &&
+		       !virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
+			sb_id++;
+		if (sb_id >= vm->nb_sb_per_mb)
+			break;
+
+		start_pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +
+				     sb_id * vm->subblock_size);
+		rc = alloc_contig_range(start_pfn, start_pfn + nr_pages,
+					MIGRATE_MOVABLE, GFP_KERNEL);
+		if (rc == -ENOMEM)
+			/* whoops, out of memory */
+			return rc;
+		if (rc)
+			/* memory busy, we can't unplug this chunk */
+			continue;
+
+		/* Mark it as fake-offline before unplugging it */
+		virtio_mem_set_fake_offline(start_pfn, nr_pages, true);
+		adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages);
+
+		/* Try to unplug the allocated memory */
+		rc = virtio_mem_mb_unplug_sb(vm, mb_id, sb_id, 1);
+		if (rc) {
+			/* Return the memory to the buddy. */
+			virtio_mem_fake_online(start_pfn, nr_pages);
+			return rc;
+		}
+
+		virtio_mem_mb_set_state(vm, mb_id,
+					VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL);
+		*nb_sb -= 1;
+	}
+
+	/*
+	 * TODO: Once all subblocks of a memory block were unplugged, we want
+	 * to offline the memory block and remove it.
+	 */
+	return 0;
+}
+
 /*
  * Try to unplug the requested amount of memory.
  */
@@ -1225,8 +1324,37 @@ static int virtio_mem_unplug_request(struct virtio_mem *vm, uint64_t diff)
 		cond_resched();
 	}
 
+	if (!unplug_online) {
+		mutex_unlock(&vm->hotplug_mutex);
+		return 0;
+	}
+
+	/* Try to unplug subblocks of partially plugged online blocks. */
+	virtio_mem_for_each_mb_state_rev(vm, mb_id,
+					 VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL) {
+		rc = virtio_mem_mb_unplug_any_sb_online(vm, mb_id,
+							&nb_sb);
+		if (rc || !nb_sb)
+			goto out_unlock;
+		mutex_unlock(&vm->hotplug_mutex);
+		cond_resched();
+		mutex_lock(&vm->hotplug_mutex);
+	}
+
+	/* Try to unplug subblocks of plugged online blocks. */
+	virtio_mem_for_each_mb_state_rev(vm, mb_id,
+					 VIRTIO_MEM_MB_STATE_ONLINE) {
+		rc = virtio_mem_mb_unplug_any_sb_online(vm, mb_id,
+							&nb_sb);
+		if (rc || !nb_sb)
+			goto out_unlock;
+		mutex_unlock(&vm->hotplug_mutex);
+		cond_resched();
+		mutex_lock(&vm->hotplug_mutex);
+	}
+
 	mutex_unlock(&vm->hotplug_mutex);
-	return 0;
+	return nb_sb ? -EBUSY : 0;
 out_unlock:
 	mutex_unlock(&vm->hotplug_mutex);
 	return rc;
@@ -1332,7 +1460,8 @@ retry:
 	case -EBUSY:
 		/*
 		 * The hypervisor cannot process our request right now
-		 * (e.g., out of memory, migrating).
+		 * (e.g., out of memory, migrating) or we cannot free up
+		 * any memory to unplug it (all plugged memory is busy).
 		 */
 	case -ENOMEM:
 		/* Out of memory, try again later. */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 13cc653122b7..ce1c9df54eac 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8603,6 +8603,7 @@ done:
 				pfn_max_align_up(end), migratetype);
 	return ret;
 }
+EXPORT_SYMBOL(alloc_contig_range);
 
 static int __alloc_contig_pages(unsigned long start_pfn,
 				unsigned long nr_pages, gfp_t gfp_mask)
@@ -8718,6 +8719,7 @@ void free_contig_range(unsigned long pfn, unsigned int nr_pages)
 	}
 	WARN(count != 0, "%d pages are still in use!\n", count);
 }
+EXPORT_SYMBOL(free_contig_range);
 
 /*
  * The zone indicated has a new number of managed_pages; batch sizes and percpu