@@ -993,6 +993,23 @@ static int virtballoon_probe(struct virtio_device *vdev)
goto out_unregister_oom;
}
+ /*
+ * The default page reporting order is @pageblock_order, which
+ * corresponds to 512MB in size on ARM64 when 64KB base page
+ * size is used. The page reporting won't be triggered if the
+ * freeing page can't come up with a free area like that huge.
+ * So we specify the page reporting order to 5, corresponding
+ * to 2MB. It helps to avoid THP splitting if 4KB base page
+ * size is used by host.
+ *
+ * Ideally, the page reporting order is selected based on the
+ * host's base page size. However, it needs more work to report
+ * that value. The hard-coded order would be fine currently.
+ */
+#if defined(CONFIG_ARM64) && defined(CONFIG_ARM64_64K_PAGES)
+ vb->pr_dev_info.order = 5;
+#endif
+
err = page_reporting_register(&vb->pr_dev_info);
if (err)
goto out_unregister_oom;
The page reporting won't be triggered if the freeing page can't come up with a free area, whose size is equal or bigger than the threshold (page reporting order). The default page reporting order, equal to @pageblock_order, is too huge on some architectures to trigger page reporting. One example is ARM64 when 64KB base page size is used. PAGE_SIZE: 64KB pageblock_order: 13 (512MB) MAX_ORDER: 14 This specifies the page reporting order to 5 (2MB) for this specific case so that page reporting can be triggered. Cc: Michael S. Tsirkin <mst@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: virtualization@lists.linux-foundation.org Signed-off-by: Gavin Shan <gshan@redhat.com> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com> --- drivers/virtio/virtio_balloon.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)