On Mon, Aug 05, 2019 at 09:16:24AM +0800, Ivan Ren wrote: >On Mon, Aug 5, 2019 at 8:34 AM Wei Yang <richardw.y...@linux.intel.com> wrote: >> >> On Fri, Aug 02, 2019 at 06:18:41PM +0800, Ivan Ren wrote: >> >From: Ivan Ren <ivan...@tencent.com> >> > >> >This patch fix a multifd migration bug in migration speed calculation, this >> >problem can be reproduced as follows: >> >1. start a vm and give a heavy memory write stress to prevent the vm be >> > successfully migrated to destination >> >2. begin a migration with multifd >> >3. migrate for a long time [actually, this can be measured by transferred >> >bytes] >> >4. migrate cancel >> >5. begin a new migration with multifd, the migration will directly run into >> > migration_completion phase >> > >> >Reason as follows: >> > >> >Migration update bandwidth and s->threshold_size in function >> >migration_update_counters after BUFFER_DELAY time: >> > >> > current_bytes = migration_total_bytes(s); >> > transferred = current_bytes - s->iteration_initial_bytes; >> > time_spent = current_time - s->iteration_start_time; >> > bandwidth = (double)transferred / time_spent; >> > s->threshold_size = bandwidth * s->parameters.downtime_limit; >> > >> >In multifd migration, migration_total_bytes function return >> >qemu_ftell(s->to_dst_file) + ram_counters.multifd_bytes. >> >s->iteration_initial_bytes will be initialized to 0 at every new migration, >> >but ram_counters is a global variable, and history migration data will be >> >accumulated. So if the ram_counters.multifd_bytes is big enough, it may lead >> >pending_size >= s->threshold_size become false in migration_iteration_run >> >after the first migration_update_counters. >> > >> >Signed-off-by: Ivan Ren <ivan...@tencent.com> >> >Reviewed-by: Juan Quintela <quint...@redhat.com> >> >Suggested-by: Wei Yang <richardw.y...@linux.intel.com> >> >--- >> >v2->v3: >> >- fix the bug of update_iteration_initial_status function prototype >> > >> >> Code looks good. Have you verified on this version? > >Yes > >> BTW, you didn't address the multifd count in this patch, right? > >Yes. >Currently multifd page count has no harm, so I think it's better to >optimize it in a new patch to make things clearer.
Fine. Reviewed-by: Wei Yang <richardw.y...@linux.intel.com> > >Thanks. -- Wei Yang Help you, Help me
