From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: avi@redhat.com, mtosatti@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] KVM: Switch to srcu-less get_dirty_log()
Date: Mon, 19 Mar 2012 17:34:49 +0800 [thread overview]
Message-ID: <4F66FDB9.1000306@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120316184459.3c64c8cf.yoshikawa.takuya@oss.ntt.co.jp>
On 03/16/2012 05:44 PM, Takuya Yoshikawa wrote:
> On Fri, 16 Mar 2012 16:28:56 +0800
> Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> wrote:
>
>> Thanks for your explanation, maybe you are right, i do not know migration
>> much.
>>
>> What i worried about is, you have changed the behaviour of GET_DIRTY_LOG,
>> in the current one, it can get all the dirty pages when it is called; after
>> your change, GET_DIRTY_LOG can get a empty dirty bitmap but dirty page exists.
>
> The current code also see the same situation because nothing prevents the
> guest from writing to pages before GET_DIRTY_LOG returns and the userspace
> checks the bitmap. Everything is running.
>
The current code is under the protection of s-rcu:
IIRC, it always holds s-rcu when write guest page and set dirty bit,
that mean the dirty page is logged either in the old dirty_bitmap or in the
current memslot->dirty_bitmap. Yes?
next prev parent reply other threads:[~2012-03-19 9:34 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-01 10:30 [PATCH 0/4] KVM: srcu-less dirty logging -v2 Takuya Yoshikawa
2012-03-01 10:31 ` [PATCH 1/4] KVM: MMU: Split the main body of rmap_write_protect() off from others Takuya Yoshikawa
2012-03-12 7:39 ` Takuya Yoshikawa
2012-03-12 7:52 ` Takuya Yoshikawa
2012-03-01 10:32 ` [PATCH 2/4] KVM: Avoid checking huge page mappings in get_dirty_log() Takuya Yoshikawa
2012-03-02 2:56 ` Takuya Yoshikawa
2012-03-02 5:11 ` Takuya Yoshikawa
2012-03-12 18:04 ` Avi Kivity
2012-03-13 9:20 ` Takuya Yoshikawa
2012-03-13 10:12 ` Avi Kivity
2012-03-13 23:04 ` Marcelo Tosatti
2012-03-14 1:04 ` Takuya Yoshikawa
2012-03-14 5:34 ` Takuya Yoshikawa
2012-03-14 10:58 ` Marcelo Tosatti
2012-03-01 10:33 ` [PATCH 3/4] KVM: Switch to srcu-less get_dirty_log() Takuya Yoshikawa
2012-03-03 5:21 ` [PATCH 3/4 changelog-v2] " Takuya Yoshikawa
2012-03-06 11:15 ` Marcelo Tosatti
2012-03-06 14:43 ` Takuya Yoshikawa
2012-03-06 15:01 ` Marcelo Tosatti
2012-03-06 15:23 ` Takuya Yoshikawa
2012-03-06 15:28 ` Marcelo Tosatti
2012-03-07 8:07 ` Takuya Yoshikawa
2012-03-07 23:25 ` Marcelo Tosatti
2012-03-08 1:35 ` Takuya Yoshikawa
2012-03-09 0:08 ` Marcelo Tosatti
2012-03-12 12:05 ` Avi Kivity
2012-03-07 8:18 ` Takuya Yoshikawa
2012-03-07 23:20 ` Marcelo Tosatti
2012-03-16 5:03 ` [PATCH 3/4] " Xiao Guangrong
2012-03-16 6:55 ` Takuya Yoshikawa
2012-03-16 7:30 ` Xiao Guangrong
2012-03-16 7:55 ` Takuya Yoshikawa
2012-03-16 8:28 ` Xiao Guangrong
2012-03-16 9:44 ` Takuya Yoshikawa
2012-03-19 9:34 ` Xiao Guangrong [this message]
2012-03-19 10:15 ` Takuya Yoshikawa
2012-03-01 10:34 ` [PATCH 4/4] KVM: Remove unused dirty_bitmap_head and nr_dirty_pages Takuya Yoshikawa
2012-03-03 5:12 ` [PATCH 0/4] KVM: srcu-less dirty logging -v2 Takuya Yoshikawa
2012-03-20 14:43 ` Avi Kivity
-- strict thread matches above, loose matches on Subject: below --
2012-02-23 11:33 [PATCH 0/4] KVM: srcu-less dirty logging Takuya Yoshikawa
2012-02-23 11:35 ` [PATCH 3/4] KVM: Switch to srcu-less get_dirty_log() Takuya Yoshikawa
2012-02-28 11:46 ` Avi Kivity
2012-02-29 7:49 ` Takuya Yoshikawa
2012-02-29 9:25 ` Avi Kivity
2012-02-29 10:16 ` Takuya Yoshikawa
2012-02-29 12:27 ` Avi Kivity
2012-02-29 14:18 ` Takuya Yoshikawa
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