Re: [PATCH v4 0/4] KVM statistics data fd-based binary interface

[Paolo Bonzini <pbonzini@redhat.com>]

On 10/05/21 20:57, Jing Zhang wrote:
> Hi Paolo,
> 
> On Thu, Apr 29, 2021 at 3:37 PM Jing Zhang <jingzhangos@google.com> wrote:
>>
>> This patchset provides a file descriptor for every VM and VCPU to read
>> KVM statistics data in binary format.
>> It is meant to provide a lightweight, flexible, scalable and efficient
>> lock-free solution for user space telemetry applications to pull the
>> statistics data periodically for large scale systems. The pulling
>> frequency could be as high as a few times per second.
>> In this patchset, every statistics data are treated to have some
>> attributes as below:
>>    * architecture dependent or common
>>    * VM statistics data or VCPU statistics data
>>    * type: cumulative, instantaneous,
>>    * unit: none for simple counter, nanosecond, microsecond,
>>      millisecond, second, Byte, KiByte, MiByte, GiByte. Clock Cycles
>> Since no lock/synchronization is used, the consistency between all
>> the statistics data is not guaranteed. That means not all statistics
>> data are read out at the exact same time, since the statistics date
>> are still being updated by KVM subsystems while they are read out.
>>
>> ---
>>
>> * v3 -> v4
>>    - Rebase to kvm/queue, commit 9f242010c3b4 ("KVM: avoid "deadlock"
>>      between install_new_memslots and MMU notifier")
>>    - Use C-stype comments in the whole patch
>>    - Fix wrong count for x86 VCPU stats descriptors
>>    - Fix KVM stats data size counting and validity check in selftest
>>
>> * v2 -> v3
>>    - Rebase to kvm/queue, commit edf408f5257b ("KVM: avoid "deadlock"
>>      between install_new_memslots and MMU notifier")
>>    - Resolve some nitpicks about format
>>
>> * v1 -> v2
>>    - Use ARRAY_SIZE to count the number of stats descriptors
>>    - Fix missing `size` field initialization in macro STATS_DESC
>>
>> [1] https://lore.kernel.org/kvm/20210402224359.2297157-1-jingzhangos@google.com
>> [2] https://lore.kernel.org/kvm/20210415151741.1607806-1-jingzhangos@google.com
>> [3] https://lore.kernel.org/kvm/20210423181727.596466-1-jingzhangos@google.com
>>
>> ---
>>
>> Jing Zhang (4):
>>    KVM: stats: Separate common stats from architecture specific ones
>>    KVM: stats: Add fd-based API to read binary stats data
>>    KVM: stats: Add documentation for statistics data binary interface
>>    KVM: selftests: Add selftest for KVM statistics data binary interface
>>
>>   Documentation/virt/kvm/api.rst                | 171 ++++++++
>>   arch/arm64/include/asm/kvm_host.h             |   9 +-
>>   arch/arm64/kvm/guest.c                        |  42 +-
>>   arch/mips/include/asm/kvm_host.h              |   9 +-
>>   arch/mips/kvm/mips.c                          |  67 ++-
>>   arch/powerpc/include/asm/kvm_host.h           |   9 +-
>>   arch/powerpc/kvm/book3s.c                     |  68 +++-
>>   arch/powerpc/kvm/book3s_hv.c                  |  12 +-
>>   arch/powerpc/kvm/book3s_pr.c                  |   2 +-
>>   arch/powerpc/kvm/book3s_pr_papr.c             |   2 +-
>>   arch/powerpc/kvm/booke.c                      |  63 ++-
>>   arch/s390/include/asm/kvm_host.h              |   9 +-
>>   arch/s390/kvm/kvm-s390.c                      | 133 +++++-
>>   arch/x86/include/asm/kvm_host.h               |   9 +-
>>   arch/x86/kvm/x86.c                            |  71 +++-
>>   include/linux/kvm_host.h                      | 132 +++++-
>>   include/linux/kvm_types.h                     |  12 +
>>   include/uapi/linux/kvm.h                      |  50 +++
>>   tools/testing/selftests/kvm/.gitignore        |   1 +
>>   tools/testing/selftests/kvm/Makefile          |   3 +
>>   .../testing/selftests/kvm/include/kvm_util.h  |   3 +
>>   .../selftests/kvm/kvm_bin_form_stats.c        | 380 ++++++++++++++++++
>>   tools/testing/selftests/kvm/lib/kvm_util.c    |  11 +
>>   virt/kvm/kvm_main.c                           | 237 ++++++++++-
>>   24 files changed, 1415 insertions(+), 90 deletions(-)
>>   create mode 100644 tools/testing/selftests/kvm/kvm_bin_form_stats.c
>>
>>
>> base-commit: 9f242010c3b46e63bc62f08fff42cef992d3801b
>> --
>> 2.31.1.527.g47e6f16901-goog
>>
> 
> Do I need to send another version for this?

No, the merge window has just finished and I wanted to flush the dozens 
of bugfix patches that I had.  I'll get to it shortly.

Paolo