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Re: [Qemu-devel] [PATCH v4 1/1] Make qemu_peek_buffer loop until it gets
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v4 1/1] Make qemu_peek_buffer loop until it gets it's data |
Date: |
Wed, 9 Apr 2014 13:59:19 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
* ???? (address@hidden) wrote:
>
> > * ???? (address@hidden) wrote:
> >>
> >>> * ???? (address@hidden) wrote:
> >>>>
> >>>> ?? 2014??4??8????????10:29??Dr. David Alan Gilbert (git)
> >>>> <address@hidden> ??????
> >>>>
> >>>>> From: "Dr. David Alan Gilbert" <address@hidden>
> >>>>>
> >>>>> Make qemu_peek_buffer repeatedly call fill_buffer until it gets
> >>>>> all the data it requires, or until there is an error.
> >>>>>
> >>>>> At the moment, qemu_peek_buffer will try one qemu_fill_buffer if there
> >>>>> isn't enough data waiting, however the kernel is entitled to return
> >>>>> just a few bytes, and still leave qemu_peek_buffer with less bytes
> >>>>> than it needed. I've seen this fail in a dev world, and I think it
> >>>>> could theoretically fail in the peeking of the subsection headers in
> >>>>> the current world.
> >>>> hmm, I also have got some errors(infrequently). Maybe It is one point.
> >>>> Could you show some messages about the error?
> >>>
> >>> I've only seen the errors in my visitor/ber world where I use the
> >>> peek_buffer
> >>> a lot more; but the one place it is used in the existing code is in
> >>> the code to check if we have the start of a subsection; if that goes wrong
> >>> I'm not sure what error would be produced.
> >>>
> >>> Dave
> >> In my observation, error is more likely to happen if migration thread is
> >> blocked too long.
> >> BTW, xbzrle and auto convergence are disable.
> >
> > What error do you see?
> >
> > Dave
> It likes section id 1 load failed at dest side.
Our migration errors aren't particularly descriptive :-(
However, try it with this patch - I'd be interested if it makes
your problem go away.
Dave
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK