From: Xiao Guangrong <guangrong.xiao@gmail.com>
To: Peter Xu <peterx@redhat.com>
Cc: kvm@vger.kernel.org, mst@redhat.com, mtosatti@redhat.com,
Xiao Guangrong <xiaoguangrong@tencent.com>,
dgilbert@redhat.com, qemu-devel@nongnu.org, wei.w.wang@intel.com,
jiang.biao2@zte.com.cn, pbonzini@redhat.com
Subject: Re: [PATCH v2 6/8] migration: move handle of zero page to the thread
Date: Tue, 24 Jul 2018 15:39:00 +0800 [thread overview]
Message-ID: <0647863e-dd2e-a761-9c3c-7a24b11a5f01@gmail.com> (raw)
In-Reply-To: <20180723094021.GN2491@xz-mi>
On 07/23/2018 05:40 PM, Peter Xu wrote:
> On Mon, Jul 23, 2018 at 04:44:49PM +0800, Xiao Guangrong wrote:
>
> [...]
>
>>>>
>>>> However, it is not safe to do ram_release_pages in the thread as it's
>>>> not protected it multithreads. Fortunately, compression will be disabled
>>>> if it switches to post-copy, so i preferred to keep current behavior and
>>>> deferred to fix it after this patchset has been merged.
>>>
>>> Do you mean ram_release_pages() is not thread-safe? Why? I didn't
>>> notice it before but I feel like it is safe.
>>
>> bitmap_clear() called in the function is not safe.
>
> Yeah, and the funny thing is that I don't think ram_release_pages()
> should even touch the receivedmap... It's possible that the
> release-ram feature for postcopy is broken.
>
> Never mind on that. I'll post a patch to fix it, then I think the
> ram_release_pages() will be thread safe.
>
> Then this patch shouldn't be affected and it should be fine after that
> fix
That would be great, thanks for your work.
next prev parent reply other threads:[~2018-07-24 7:39 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-19 12:15 [PATCH v2 0/8] migration: compression optimization guangrong.xiao
2018-07-19 12:15 ` [PATCH v2 1/8] migration: do not wait for free thread guangrong.xiao
2018-07-23 3:25 ` Peter Xu
2018-07-23 7:16 ` Xiao Guangrong
2018-07-23 18:36 ` Eric Blake
2018-07-24 7:40 ` Xiao Guangrong
2018-07-19 12:15 ` [PATCH v2 2/8] migration: fix counting normal page for compression guangrong.xiao
2018-07-23 3:33 ` Peter Xu
2018-07-19 12:15 ` [PATCH v2 3/8] migration: show the statistics of compression guangrong.xiao
2018-07-23 4:36 ` Peter Xu
2018-07-23 7:39 ` Xiao Guangrong
2018-07-23 8:05 ` Peter Xu
2018-07-23 8:40 ` Xiao Guangrong
2018-07-23 9:15 ` Peter Xu
2018-07-24 7:37 ` Xiao Guangrong
2018-07-25 16:44 ` Dr. David Alan Gilbert
2018-07-26 5:29 ` Peter Xu
2018-07-19 12:15 ` [PATCH v2 4/8] migration: introduce save_zero_page_to_file guangrong.xiao
2018-07-23 4:40 ` Peter Xu
2018-07-19 12:15 ` [PATCH v2 5/8] migration: drop the return value of do_compress_ram_page guangrong.xiao
2018-07-23 4:48 ` Peter Xu
2018-07-19 12:15 ` [PATCH v2 6/8] migration: move handle of zero page to the thread guangrong.xiao
2018-07-23 5:03 ` Peter Xu
2018-07-23 7:56 ` Xiao Guangrong
2018-07-23 8:28 ` Peter Xu
2018-07-23 8:44 ` Xiao Guangrong
2018-07-23 9:40 ` Peter Xu
2018-07-24 7:39 ` Xiao Guangrong [this message]
2018-07-19 12:15 ` [PATCH v2 7/8] migration: hold the lock only if it is really needed guangrong.xiao
2018-07-23 5:36 ` Peter Xu
2018-07-19 12:15 ` [PATCH v2 8/8] migration: do not flush_compressed_data at the end of each iteration guangrong.xiao
2018-07-23 5:49 ` Peter Xu
2018-07-23 8:05 ` Xiao Guangrong
2018-07-23 8:35 ` Peter Xu
2018-07-23 8:53 ` Xiao Guangrong
2018-07-23 9:01 ` Peter Xu
2018-07-24 7:29 ` Xiao Guangrong
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