Re: [PATCH v6 09/18] tools/libxl: introduce libxl__domain_common_switch_qemu_logdirty()

From: Wen Congyang <wency@cn.fujitsu.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Lars Kurth <lars.kurth@citrix.com>,
	Changlong Xie <xiecl.fnst@cn.fujitsu.com>,
	Wei Liu <wei.liu2@citrix.com>,
	Ian Campbell <ian.campbell@citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Jiang Yunhong <yunhong.jiang@intel.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	xen devel <xen-devel@lists.xen.org>,
	Dong Eddie <eddie.dong@intel.com>,
	Gui Jianfeng <guijianfeng@cn.fujitsu.com>,
	Shriram Rajagopalan <rshriram@cs.ubc.ca>,
	Yang Hongyang <hongyang.yang@easystack.cn>
Subject: Re: [PATCH v6 09/18] tools/libxl: introduce libxl__domain_common_switch_qemu_logdirty()
Date: Wed, 27 Jan 2016 10:06:08 +0800	[thread overview]
Message-ID: <56A82610.8020505@cn.fujitsu.com> (raw)
In-Reply-To: <20160126142742.GA19666@char.us.oracle.com>

On 01/26/2016 10:27 PM, Konrad Rzeszutek Wilk wrote:
> On Tue, Jan 26, 2016 at 03:04:39PM +0800, Wen Congyang wrote:
>> On 01/26/2016 02:59 AM, Konrad Rzeszutek Wilk wrote:
>>> On Wed, Dec 30, 2015 at 10:28:59AM +0800, Wen Congyang wrote:
>>>> Secondary vm is running in colo mode, we need to send
>>>> secondary vm's dirty page information to master at checkpoint,
>>>
>>> In previous patch you called it primary, so perhaps:
>>> s/master/primary/ ?
>>>
>>>> so we have to enable qemu logdirty on secondary.
>>>>
>>>> libxl__domain_suspend_common_switch_qemu_logdirty() is to enable
>>>> qemu logdirty. But it uses domain_save_state, and calls
>>>
>>> s/domain_save_state/libxl__domain_save_state/
>>>> libxl__xc_domain_saverestore_async_callback_done()
>>>> before exits. This can not be used for secondary vm.
>>>>
>>>> Update libxl__domain_suspend_common_switch_qemu_logdirty() to
>>>> introduce a new API libxl__domain_common_switch_qemu_logdirty().
>>>> This API only uses libxl__logdirty_switch, and calls
>>>> lds->callback before exits.
>>>
>>> One question - that perhaps had been part of the review earlier
>>> (if so it may be good to include this in the description
>>> so I don't ask silly questions):
>>>
>>> Why add this extra API? You could squash libxl__domain_suspend_common_switch_qemu_logdirty
>>> and libxl__domain_common_switch_qemu_logdirty code together
>>> and call it libxl_domain_common_and_suspend_common_switch_qemu_logdirty
>>> (ok, just kidding on the name). But - why not have one function
>>> instead of splitting the functionality in two?
>>
>> Do you mean that auto switch qemu logdirty when suspend the guest?
> 
> Squash the two functions - libxl__domain_common_switch_qemu_logdirty and
> libxl__domain_suspend_common_switch_qemu_logdirty together?

No, libxl__domain_suspend_common_switch_qemu_logdirty() is used by save side.
libxl__domain_common_switch_qemu_logdirty() will be used by restore side. Please
see the patch 11 in another series.

Thanks
Wen Congyang

> 
> 
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