[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4 1/5] remus: don't call stream_continue() when doing failover
On 01/19/2016 12:45 AM, Ian Campbell wrote: > 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 <wency@xxxxxxxxxxxxxx> >> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> >> --- >> 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". Sorry for may poor English... I will fix it in the next version. > > - 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? I will check the code first. I think xc_domain_restore() should not return 0 if it doesn't receive a single CHECKPOINT_END. Thanks Wen Congyang > > Ian. > > > . > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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