* Peter Xu (pet...@redhat.com) wrote: > v2: Queued
> - add r-bs for Dave > - add patch "migration: Properly destroy variables on incoming side" as patch > 1 > - destroy page_request_mutex in migration_incoming_state_destroy() too [Dave] > - use WITH_QEMU_LOCK_GUARD in two places where we can [Dave] > > We've seen conditional guest hangs on destination VM after postcopy recovered. > However the hang will resolve itself after a few minutes. > > The problem is: after a postcopy recovery, the prioritized postcopy queue on > the source VM is actually missing. So all the faulted threads before the > postcopy recovery happened will keep halted until (accidentally) the page got > copied by the background precopy migration stream. > > The solution is to also refresh this information after postcopy recovery. To > achieve this, we need to maintain a list of faulted addresses on the > destination node, so that we can resend the list when necessary. This work is > done via patch 2-5. > > With that, the last thing we need to do is to send this extra information to > source VM after recovered. Very luckily, this synchronization can be > "emulated" by sending a bunch of page requests (although these pages have been > sent previously!) to source VM just like when we've got a page fault. Even in > the 1st version of the postcopy code we'll handle duplicated pages well. So > this fix does not even need a new capability bit and it'll work smoothly on > old > QEMUs when we migrate from them to the new QEMUs. > > Please review, thanks. > > Peter Xu (6): > migration: Properly destroy variables on incoming side > migration: Rework migrate_send_rp_req_pages() function > migration: Pass incoming state into qemu_ufd_copy_ioctl() > migration: Introduce migrate_send_rp_message_req_pages() > migration: Maintain postcopy faulted addresses > migration: Sync requested pages after postcopy recovery > > migration/migration.c | 79 +++++++++++++++++++++++++++++++++++----- > migration/migration.h | 23 +++++++++++- > migration/postcopy-ram.c | 46 ++++++++++------------- > migration/savevm.c | 57 +++++++++++++++++++++++++++++ > migration/trace-events | 3 ++ > 5 files changed, 171 insertions(+), 37 deletions(-) > > -- > 2.26.2 > > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK