[libvirt] [PATCH] doc: blkio: add some notification

[Gao feng]

On 07/03/2013 03:01 AM, Eric Blake wrote:
> On 07/02/2013 02:44 AM, Gao feng wrote:
>> If the I/O elevator of disk is not cfq, the setting
>> of blkio.weight is ineffective. And the setting up
>> blkio.weight_device will fail.
>>
>> Add notification for this situation.
>>
>> Signed-off-by: Gao feng <gaofeng at cn.fujitsu.com>
>> ---
>>  docs/formatdomain.html.in | 6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
>> index 47d91ab..8d048be 100644
>> --- a/docs/formatdomain.html.in
>> +++ b/docs/formatdomain.html.in
>> @@ -740,7 +740,8 @@
>>        <dd> The optional <code>blkiotune</code> element provides the ability
>>          to tune Blkio cgroup tunable parameters for the domain. If this is
>>          omitted, it defaults to the OS provided
>> -        defaults. <span class="since">Since 0.8.8</span></dd>
>> +        defaults. Notice: blkiotune is effective only when the I/O elevator
>> +        of disk is cfq. <span class="since">Since 0.8.8</span></dd>
> 
> This is terminology specific to the Linux kernel; would it help to add a
> phrase explaining that?  Maybe something like:
> 
> Notice: blkiotune is effective only when the host kernel uses the 'cfq'
> I/O elevator for the disk.
> 

Yes, this looks better.

> I like the idea of the patch, but am not sure that I know enough about
> kernel internals to state whether your wording or my alternative is good
> enough at getting the point across correctly to someone else not very
> familiar with kernel concepts.
> 

take easy, I'm working on enhancing the warn/error log for libvirt in this
situation. I think it's clear enough if we provide some logs to the user.