On Mon, 2016-01-18 at 13:40 +0800, Wen Congyang wrote:
> stream_continue() is used for migration to read emulator
> xenstore data and emulator context. For remus, if we do
> failover, we have read it in the checkpoint cycle, and
> we only need to complete the stream.
>
> Signed-off-by: Wen Congyang <we...@cn.fujitsu.com>
> Reviewed-by: Andrew Cooper <andrew.coop...@citrix.com>
> ---
> tools/libxl/libxl_stream_read.c | 35 ++++++++++++++++++++++++++++++-----
> 1 file changed, 30 insertions(+), 5 deletions(-)
>
> diff --git a/tools/libxl/libxl_stream_read.c
> b/tools/libxl/libxl_stream_read.c
> index 258dec4..24305f4 100644
> --- a/tools/libxl/libxl_stream_read.c
> +++ b/tools/libxl/libxl_stream_read.c
> @@ -101,6 +101,19 @@
> * - stream_write_emulator_done()
> * - stream_continue()
> *
> + * 4) Failover for remus
I don't think this is really #4 in the list which precedes it. I think a
section "Failover for remus" would be absolutely fine right that the end of
this comment block though, i.e. right after the "Depending on the
contents..." paragraph.
Andy?
> + * - we buffer all records until a CHECKPOINT_END record is received
> + * - we will use the records when a CHECKPOINT_END record is received
"we will consume the buffered records..."
> + * - if we find some internal error, the rc or retval is not 0 in
s/the/then/
> + * libxl__xc_domain_restore_done(). In this case, we don't resume the
> + * guest
> + * - if we need to do failover from primary, the rc and retval are 0
s/the/then/ again and I would say "are both 0" for clarity (assuming that
is indeed the requirement).
> + * in libxl__xc_domain_restore_done(). In this case, the buffered state
> + * will be dropped, because we don't receive a CHECKPOINT_END record,
haven't received
> + * and it is a inconsistent state. In libxl__xc_domain_restore_done(),
"an inconsistent".
I think I would say "... and therefore the buffered state is inconsistent".
- stream_continue(egc, stream);
> + if (checkpointed_stream) {
> + /*
> + * Failover from primary. Domain state is currently at a
> + * consistent checkpoint, complete the stream, and call
> + * stream->completion_callback() to resume the guest.
> + */
> + stream_complete(egc, stream, 0);
Is it possible to get here having never received a single CHECKPOINT_END?
Ian.
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