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Re: [Qemu-devel] [PATCH v2 6/8] migration: move handle of zero page to t
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [PATCH v2 6/8] migration: move handle of zero page to the thread |
Date: |
Mon, 23 Jul 2018 17:40:21 +0800 |
User-agent: |
Mutt/1.10.0 (2018-05-17) |
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.
Regards,
--
Peter Xu
- Re: [Qemu-devel] [PATCH v2 3/8] migration: show the statistics of compression, (continued)
[Qemu-devel] [PATCH v2 8/8] migration: do not flush_compressed_data at the end of each iteration, guangrong . xiao, 2018/07/19
- Re: [Qemu-devel] [PATCH v2 8/8] migration: do not flush_compressed_data at the end of each iteration, Peter Xu, 2018/07/23
- Re: [Qemu-devel] [PATCH v2 8/8] migration: do not flush_compressed_data at the end of each iteration, Xiao Guangrong, 2018/07/23
- Re: [Qemu-devel] [PATCH v2 8/8] migration: do not flush_compressed_data at the end of each iteration, Peter Xu, 2018/07/23
- Re: [Qemu-devel] [PATCH v2 8/8] migration: do not flush_compressed_data at the end of each iteration, Xiao Guangrong, 2018/07/23
- Re: [Qemu-devel] [PATCH v2 8/8] migration: do not flush_compressed_data at the end of each iteration, Peter Xu, 2018/07/23
- Re: [Qemu-devel] [PATCH v2 8/8] migration: do not flush_compressed_data at the end of each iteration, Xiao Guangrong, 2018/07/24
[Qemu-devel] [PATCH v2 7/8] migration: hold the lock only if it is really needed, guangrong . xiao, 2018/07/19