Hi Paolo,
On 5/9/23 12:21 PM, Gavin Shan wrote:
> This series intends to support dirty ring for live migration for arm64. The
> dirty ring use discrete buffer to track dirty pages. For arm64, the speciality
> is to use backup bitmap to track dirty pages when there is no-running-vcpu
> context. It's known that the backup bitmap needs to be synchronized when
> KVM device "kvm-arm-gicv3" or "arm-its-kvm" has been enabled. The backup
> bitmap is collected in the last stage of migration. The policy here is to
> always enable the backup bitmap extension. The overhead to synchronize the
> backup bitmap in the last stage of migration, when those two devices aren't
> used, is introduced. However, the overhead should be very small and acceptable.
> The benefit is to support future cases where those two devices are used without
> modifying the code.
>
> PATCH[1] add migration last stage indicator
> PATCH[2] synchronize the backup bitmap in the last stage of migration
> PATCH[3] add helper kvm_dirty_ring_init() to enable dirty ring
> PATCH[4] enable dirty ring for arm64
>
> v2: https://lists.nongnu.org/archive/html/qemu-arm/2023-02/msg01342.html
> v1: https://lists.nongnu.org/archive/html/qemu-arm/2023-02/msg00434.html
> RFCv1: https://lists.nongnu.org/archive/html/qemu-arm/2023-02/msg00171.html
>
> Testing
> =======
> (1) kvm-unit-tests/its-pending-migration and kvm-unit-tests/its-migration with
> dirty ring or normal dirty page tracking mechanism. All test cases passed.
>
> QEMU=./qemu.main/build/qemu-system-aarch64 ACCEL=kvm \
> ./its-pending-migration
>
> QEMU=./qemu.main/build/qemu-system-aarch64 ACCEL=kvm \
> ./its-migration
>
> QEMU=./qemu.main/build/qemu-system-aarch64 ACCEL=kvm,dirty-ring-size=65536 \
> ./its-pending-migration
>
> QEMU=./qemu.main/build/qemu-system-aarch64 ACCEL=kvm,dirty-ring-size=65536 \
> ./its-migration
>
> (2) Combinations of migration, post-copy migration, e1000e and virtio-net
> devices. All test cases passed.
>
> -netdev tap,id=net0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown \
> -device e1000e,bus=pcie.5,netdev=net0,mac=52:54:00:f1:26:a0
>
> -netdev tap,id=vnet0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown \
> -device virtio-net-pci,bus=pcie.6,netdev=vnet0,mac=52:54:00:f1:26:b0
>
> Changelog
> =========
> v3:
> * Rebase for QEMU v8.1.0 (Gavin)
> v2:
> * Drop PATCH[v1 1/6] to synchronize linux-headers (Gavin)
> * More restrictive comments about struct MemoryListener::log_sync_global (PeterX)
> * Always enable the backup bitmap extension (PeterM)
> v1:
> * Combine two patches into one PATCH[v1 2/6] for the last stage indicator (PeterX)
> * Drop the secondary bitmap and use the original one directly (Juan)
> * Avoid "goto out" in helper kvm_dirty_ring_init() (Juan)
>
> Gavin Shan (4):
> migration: Add last stage indicator to global dirty log
> kvm: Synchronize the backup bitmap in the last stage
> kvm: Add helper kvm_dirty_ring_init()
> kvm: Enable dirty ring for arm64
>
> accel/kvm/kvm-all.c | 108 ++++++++++++++++++++++++++++-----------
> include/exec/memory.h | 7 ++-
> include/sysemu/kvm_int.h | 1 +
> migration/dirtyrate.c | 4 +-
> migration/ram.c | 20 ++++----
> softmmu/memory.c | 10 ++--
> 6 files changed, 101 insertions(+), 49 deletions(-)
>
Could you please help to take a look and queue this series for QEMU v8.1 if it looks good?
Peter Maydell has the suggestion [1] to merge the v2 series to QEMU v8.1. there is no
difference between v2 and v3 except the fixed rebase conflicts in v3.
[1] https://lists.nongnu.org/archive/html/qemu-arm/2023-03/msg00551.html
Thanks,
Gavin