Re: [Qemu-devel] [v8 Patch 0/6]Qemu: Host pagecache setting from cmdline and monitor

[Zhi Yong Wu]

On Mon, Nov 7, 2011 at 5:35 PM, Supriya Kannery
<address@hidden> wrote:
> On 11/07/2011 02:19 PM, Zhi Yong Wu wrote:
>>
>> On Mon, Nov 7, 2011 at 4:38 PM, Supriya Kannery
>> <address@hidden>  wrote:
>>>
>>> On 11/04/2011 07:59 AM, Zhi Yong Wu wrote:
>>>>
>>>> On Sun, Oct 30, 2011 at 6:33 PM, Supriya Kannery
>>>> <address@hidden>    wrote:
>>>>>
>>>>> Currently cache setting of a block device cannot be changed
>>>>> without restarting a running VM. Following patchset is for
>>>>> enabling dynamic change of cache setting for block devices
>>>>> through qemu monitor. Code changes are based on patches
>>>>> from Christoph Hellwig and Prerna Saxena.
>>>>>
>>>>> This patchset introduces
>>>>> a. monitor command 'block_set_hostcache' using which host
>>>>>   pagecache setting for a block device can be changed
>>>>>   dynamically.
>>>>
>>>> I got a bit confusion. Is it used to change host pagecache setting on
>>>> hyperviser or on guest?
>>>> This block device said by you is for guest, right?
>>>>
>>>
>>>  This command is used for changing pagecache setting of
>>> the image files in host which are acting as block devices
>>> for guest.
>>
>> So what is the difference between it and cache option?
>>
>
> Cache=xx sets a combination of status flags for image files
> among which host pagecache is just one. Intention here is
> to gradually replace cache=xx with more explicit settings
> like hostcache, flush, WCE.
Great, thanks.
>
>



-- 
Regards,

Zhi Yong Wu