Re: [Qemu-devel] [PATCH 0/6] Obtain dirty bitmap via VM logging

[ChenLiang <chenliang88@huawei.com>]

Hi,
Nice job. We should avoid running migration_thread and bitmap_logging_thread simultaneously.

Best regards:
ChenLiang

> Hi,
> 
> This is the first part of my gsoc work.
> 
> Following patches add the support of dirty bitmap logging and dumping
> to a specified file. These patches provide the mechanism to get the
> dirty bitmap if the user wants to log the VM besides migration. This
> can be useful in case of learning about the writable working set of
> the VM even when it is not being migrated. I know that it will incur
> huge degradation but still, a user might want to do that. Besides this,
> this mechanism can also be useful in case of learning about the pages
> that can be stored in the cache while performing the xbzrle based live
> migration or even before the beginning of the hybrid (precopy + postcopy)
> live migration.
> 
> I have tried to provide both of the hmp and qmp commands interface to
> obtain the dirty bitmap. Besides dumping the dirty bitmap, one can
> also update the frequency with which the logging is taking place or
> even can cancel the ongoing logging process. Thus, there are 3 hmp and
> qmp commands interface provided to perform the task.
> 
> 
> Sanidhya Kashyap (6):
>   split dirty bitmap into four for dumping the bitmaps
>   bitmap dump code via QAPI framework
>   hmp interface for dirty bitmap dump
>   cancel mechanism for an already running dump bitmap process
>   set the frequency of the dump bitmap process
>   python script for extracting bitmap from a binary file
> 
>  exec.c                    |   4 +
>  hmp-commands.hx           |  46 +++++++
>  hmp.c                     |  36 +++++
>  hmp.h                     |   3 +
>  include/exec/memory.h     |   3 +-
>  include/exec/ram_addr.h   |  16 ++-
>  include/qapi/qmp/qerror.h |   3 +
>  qapi-schema.json          |  23 ++++
>  qmp-commands.hx           |  77 +++++++++++
>  savevm.c                  | 344 ++++++++++++++++++++++++++++++++++++++++++++++
>  scripts/extract-bitmap.py |  68 +++++++++
>  11 files changed, 621 insertions(+), 2 deletions(-)
>  create mode 100755 scripts/extract-bitmap.py
>