Current QEMU live migration implementation mark all guest's RAM pages as dirtied in the ram bulk stage, all these pages will be processed and it consumes quite a lot of CPU cycles and network bandwidth. >From guest's point of view, it doesn't care about the content in free page. We can make use of this fact and skip processing the free pages, this can save a lot CPU cycles and reduce the network traffic significantly while speed up the live migration process obviously. This patch set is the kernel side implementation. The virtio-balloon driver is extended to send the free page bitmap from guest to QEMU. After getting the free page bitmap, QEMU can use it to filter out guest's free pages. This make the live migration process much more efficient. In order to skip more free pages, we add an interface to let the user decide whether dropping the cache in guest during live migration. Liang Li (2): mm: add the related functions to build the free page bitmap virtio-balloon: extend balloon driver to support the new feature drivers/virtio/virtio_balloon.c | 100 ++++++++++++++++++++++++++++++++++-- fs/drop_caches.c | 22 +++++--- include/linux/fs.h | 1 + include/uapi/linux/virtio_balloon.h | 1 + mm/page_alloc.c | 46 +++++++++++++++++ 5 files changed, 157 insertions(+), 13 deletions(-) -- 1.8.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>