From: Hailiang Zhang <zhang.zhanghailiang@huawei.com>
To: "Li, Liang Z" <liang.z.li@intel.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: "amit.shah@redhat.com" <amit.shah@redhat.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
peter.huangpeng@huawei.com,
"dgilbert@redhat.com" <dgilbert@redhat.com>,
"quintela@redhat.com" <quintela@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] migration: not send zero page header in ram bulk stage
Date: Tue, 19 Jan 2016 11:11:14 +0800 [thread overview]
Message-ID: <569DA952.3090501@huawei.com> (raw)
In-Reply-To: <F2CBF3009FA73547804AE4C663CAB28E03732BAC@SHSMSX101.ccr.corp.intel.com>
On 2016/1/19 9:26, Li, Liang Z wrote:
>> On 2016/1/15 18:24, Li, Liang Z wrote:
>>>> It seems that this patch is incorrect, if the no-zero pages are
>>>> zeroed again during !ram_bulk_stage, we didn't send the new zeroed
>>>> page, there will be an error.
>>>>
>>>
>>> If not in ram_bulk_stage, still send the header, could you explain why it's
>> wrong?
>>>
>>> Liang
>>>
>>
>> I have made a mistake, and yes, this patch can speed up the live migration
>> time, especially when there are many zero pages, it will be more obvious.
>> I like this idea. Did you test it with postcopy ? Does it break postcopy ?
>>
>
> Not yet, I saw Dave's comment's, it will beak post copy, it's not hard to fix this.
> A more important thing is Paolo's comments, I don't know in which case this patch will break LM. Do you have any idea about this?
> Hope that QEMU don't write data to the block 'pc.ram'.
>
Paolo is right, for VM in destination, QEMU may write VM's memory before VM starts.
So your assumption that "VM's RAM pages are initialized to zero" is incorrect.
This patch will break LM.
> Liang
>
>> Thanks,
>> zhanghailiang
>>
>
> .
>
next prev parent reply other threads:[~2016-01-19 3:11 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-15 9:48 [Qemu-devel] [PATCH] migration: not send zero page header in ram bulk stage Liang Li
2016-01-15 10:17 ` Hailiang Zhang
2016-01-15 10:24 ` Li, Liang Z
2016-01-18 9:01 ` Hailiang Zhang
2016-01-19 1:26 ` Li, Liang Z
2016-01-19 3:11 ` Hailiang Zhang [this message]
2016-01-19 3:17 ` Li, Liang Z
2016-01-20 9:55 ` Paolo Bonzini
2016-01-20 9:59 ` Li, Liang Z
2016-01-19 3:25 ` Hailiang Zhang
2016-01-19 3:36 ` Li, Liang Z
2016-01-15 11:39 ` Paolo Bonzini
2016-01-16 14:12 ` Li, Liang Z
2016-01-15 18:57 ` Dr. David Alan Gilbert
2016-01-16 14:25 ` Li, Liang Z
2016-01-18 9:33 ` Dr. David Alan Gilbert
2016-01-18 9:17 ` Hailiang Zhang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=569DA952.3090501@huawei.com \
--to=zhang.zhanghailiang@huawei.com \
--cc=amit.shah@redhat.com \
--cc=dgilbert@redhat.com \
--cc=liang.z.li@intel.com \
--cc=pbonzini@redhat.com \
--cc=peter.huangpeng@huawei.com \
--cc=qemu-devel@nongnu.org \
--cc=quintela@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).