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Message-ID: <4EF13206.4050902@cn.fujitsu.com>
Date: Wed, 21 Dec 2011 09:10:30 +0800
From: Wen Congyang <wency@cn.fujitsu.com>
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Subject: Re: [Qemu-devel] [RFC][PATCH 8/8 v3] introduce a new monitor
 command 'dump' to dump guest's memory
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To: Eric Blake <eblake@redhat.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>, HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>, Dave Anderson <anderson@redhat.com>, qemu-devel <qemu-devel@nongnu.org>

At 12/21/2011 12:25 AM, Eric Blake Write:
> On 12/20/2011 02:15 AM, Wen Congyang wrote:
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> ---
>>  Makefile.target |    8 +-
>>  dump.c          |  452 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  dump.h          |    4 +
>>  hmp-commands.hx |   16 ++
>>  monitor.c       |    3 +
>>  qmp-commands.hx |   24 +++
>>  6 files changed, 503 insertions(+), 4 deletions(-)
>>  create mode 100644 dump.c
>>
>> +++ b/qmp-commands.hx
>> @@ -469,6 +469,30 @@ Notes:
>>  EQMP
>>  
>>      {
>> +        .name       = "dump",
>> +        .args_type  = "file:s",
>> +        .params     = "file",
>> +        .help       = "dump to file",
>> +        .user_print = monitor_user_noop,
>> +        .mhandler.cmd_new = do_dump,
>> +    },
> 
> From a libvirt perspective, we would like the option to be able to pass
> in an already-open fd rather than just a file name.  This is possible if
> the 'file' argument is required to start with '/' for an absolute path,
> vs. 'file:name' for an fd previously passed in via the getfd monitor
> command.

file:s means the parameter is a file, and the type is string.
s can be file:path or fd:fd's name here. Sorry for confusing you.

> 
> Also, does this command block?  It sounds like it is long-running, which
> means it probably needs to be asynchronous, as well as issue an event
> upon completion, so that other monitor commands can be issued in the
> meantime.
> 
Good idea, i will try to implement it in the next version.

Thanks
Wen Congyang