[libvirt] [PATCH 1/8] Add new API virDomain{Set, Get}BlockIoTune

[Lei Li]

On 11/10/2011 04:43 AM, Eric Blake wrote:
> On 11/09/2011 01:32 PM, Lei Li wrote:
>> This patch add new pulic API virDomainSetBlockIoTune and
>> virDomainGetBlockIoTune.
>>
>>
>> Signed-off-by: Zhi Yong Wu<wuzhy at linux.vnet.ibm.com>
>> Signed-off-by: Lei Li<lilei at linux.vnet.ibm.com>
>> ---
>>   include/libvirt/libvirt.h.in |   26 +++++++++
>>   src/driver.h                 |   19 +++++++
>>   src/libvirt.c                |  115 
>> ++++++++++++++++++++++++++++++++++++++++++
>>   src/libvirt_public.syms      |    2 +
>>   4 files changed, 162 insertions(+), 0 deletions(-)
>>
>> diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
>> index aa320b6..a79c35e 100644
>> --- a/include/libvirt/libvirt.h.in
>> +++ b/include/libvirt/libvirt.h.in
>> @@ -1640,6 +1640,32 @@ int    virDomainBlockJobSetSpeed(virDomainPtr 
>> dom, const char *path,
>>   int           virDomainBlockPull(virDomainPtr dom, const char *path,
>>                                    unsigned long bandwidth, unsigned 
>> int flags);
>>
>> +/*
>> + * Block I/O throttling support
>> + */
>> +
>> +typedef struct _virDomainBlockIoTuneInfo virDomainBlockIoTuneInfo;
>> +struct _virDomainBlockIoTuneInfo {
>> +    unsigned long long total_bytes_sec;
>> +    unsigned long long read_bytes_sec;
>> +    unsigned long long write_bytes_sec;
>> +    unsigned long long total_iops_sec;
>> +    unsigned long long read_iops_sec;
>> +    unsigned long long write_iops_sec;
>> +};
>> +typedef virDomainBlockIoTuneInfo *virDomainBlockIoTuneInfoPtr;
>
> This is not extensible.  We've already learned the hard way that this 
> MUST use virTypedParameter to make future additions painless, rather 
> than hard-coding a particular structure.
>
Hi Eric,

We consider using virTypeParameter as Adam suggested at first, but when I dig into the code, I found
struct virTypedParameter is mainly used by memtune, blkiotune...etc, supported by cgroup mechanism,
different from Block I/O throttling which is supported through qemu monitor command 'block_set_io_throttle'.

Qemu monitor send all the setting parameters at one time within qmp command made by qemuMonitorJSONMakeCommand,
the union struct virTypeParameter is not very suitable for it. So we still use struct virDomainBlockIoTuneInfo
to keep consistent for qemu monitor command.

-- 
Lei