This patch set intends to do two optimizations, one is to speed up the (de)inflating process of virtio balloon, and another one which is to speed up the live migration process. We put them together because both of them are required to change the virtio balloon spec.
The main idea of speeding up the (de)inflating process is to use bitmap to send the page information to host instead of the PFNs, to reduce the overhead of virtio data transmission, address translation and madvise(). This can help to improve the performance by about 85%. The idea of speeding up live migration is to skip process guest's free pages in the first round of data copy, to reduce needless data processing, this can help to save quite a lot of CPU cycles and network bandwidth. We get guest's free page information through the virt queue of virtio-balloon, and filter out these free pages during live migration. For an idle 8GB guest, this can help to shorten the total live migration time from 2Sec to about 500ms in the 10Gbps network environment. Changes from v1 to v2: * Abandon the patch for dropping page cache. * Get a struct from vq instead of separate variables. * Use two separate APIs to request free pages and query the status. * Changed the virtio balloon interface. * Addressed some of the comments of v1. Liang Li (9): virtio-balloon: Remove needless precompiled directive virtio-balloon: update linux head file virtio-balloon: speed up inflating & deflating process virtio-balloon: update linux head file for new feature balloon: get free page info from guest balloon: migrate vq elem to destination bitmap: Add a new bitmap_move function kvm: Add two new arch specific functions migration: skip free pages during live migration balloon.c | 47 +++- hw/virtio/virtio-balloon.c | 304 ++++++++++++++++++++++-- include/hw/virtio/virtio-balloon.h | 18 +- include/qemu/bitmap.h | 13 + include/standard-headers/linux/virtio_balloon.h | 41 ++++ include/sysemu/balloon.h | 18 +- include/sysemu/kvm.h | 18 ++ migration/ram.c | 86 +++++++ target-arm/kvm.c | 14 ++ target-i386/kvm.c | 37 +++ target-mips/kvm.c | 14 ++ target-ppc/kvm.c | 14 ++ target-s390x/kvm.c | 14 ++ 13 files changed, 608 insertions(+), 30 deletions(-) -- 1.9.1