On 04 Oct 2014, at 4:21 , Dr. David Alan Gilbert <dgilb...@redhat.com> wrote:
> > I've updated our github at: > https://github.com/orbitfp7/qemu/tree/wp3-postcopy > > to have this version. > > and it corresponds to the tag: > https://github.com/orbitfp7/qemu/releases/tag/wp3-postcopy-v4 Hi Dave, I just tested this version of post-copy using the libvirt patches I recently posted and it works a lot better. The video streaming VM migrates with a downtime of less than 1 second. Before post-copy finishes, the VM is a bit slow but otherwise running well. I also tested the patches with a VM doing ‘ping’ and the downtime was around 0.6 seconds. I suspect that this delay could be caused by libvirt and not by qemu. Notice that, libvirt is a bit special, in the sense that the VM is migrated in suspended state and resumed only after the network was set up on the destination. I will investigate and let you know. Cristian > * Dr. David Alan Gilbert (git) (dgilb...@redhat.com) wrote: >> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> >> >> Hi, >> This is the 4th cut of my version of postcopy; it is designed for use with >> the Linux kernel additions just posted by Andrea Arcangeli here: >> >> http://marc.info/?l=linux-kernel&m=141235633015100&w=2 >> >> (Note: This is a new version compared to my previous postcopy patchset; >> you'll >> need to update the kernel to the new version.) >> >> Other than the new kernel ABI (which is only a small change to the userspace >> side); >> the major changes are; >> >> a) Code for host page size != target page size >> b) Support for migration over fd >> From Cristian Klein; this is for libvirt support which Cristian recently >> posted to the libvirt list. >> c) It's now build bisectable and builds on 32bit >> >> Testing wise; I've now done many thousand of postcopy migrations without >> failure (both of idle and busy guests); so it seems pretty solid. >> >> Must-TODO's: >> 1) A partially repeatable migration_cancel failure >> 2) virt_test's migrate.with_reboot test is failing >> 3) The ACPI fix in 2.1 that allowed migrating RAMBlocks to be larger than >> the source feels like it needs looking at for postcopy. >> 4) Paolo's comments with respect to the wakeup_request/is_running code >> in the migration thread >> 5) xbzrle needs disabling once in postcopy >> >> Later-TODO's: >> 1) Control the rate of background page transfers during postcopy to >> reduce their impact on the latency of postcopy requests. >> 2) Work with RDMA >> 3) Could destination RP be made blocking (as per discussion with Paolo; >> I'm still worried that that changes too many assumptions) >> >> >> >> V4: >> Initial support for host page size != target page size >> - tested heavily on hps==tps >> - only partially tested on hps!=tps systems >> - This involved quite a bit of rework around the discard code >> Updated to new kernel userfault ABI >> - It won't work with the previous version >> Fix mis-optimisation of postcopy request for wrong RAMBlock >> request for block A offset n >> un-needed fault for block B/m (already received - no req sent) >> request for block B/l - wrongly sent as request for A/l >> Fix thinko in discard bitmap processing (missed last word of bitmap) >> Symptom: remap failures near the top of RAM if postcopy started late >> Fix bug that caused kernel page acknowledgments to be misaligned >> May have meant the guest was paused for longer than required >> Fix potential for crashing cleaning up failed RP >> Fixes in docs (from Yang) >> Handle migration by fd as sockets if they are sockets >> Build tested on 32bit >> Fully build bisectable (x86-64) >> >> >> Dave >> >> Cristian Klein (1): >> Handle bi-directional communication for fd migration >> >> Dr. David Alan Gilbert (46): >> QEMUSizedBuffer based QEMUFile >> Tests: QEMUSizedBuffer/QEMUBuffer >> Start documenting how postcopy works. >> qemu_ram_foreach_block: pass up error value, and down the ramblock >> name >> improve DPRINTF macros, add to savevm >> Add qemu_get_counted_string to read a string prefixed by a count byte >> Create MigrationIncomingState >> socket shutdown >> Provide runtime Target page information >> Return path: Open a return path on QEMUFile for sockets >> Return path: socket_writev_buffer: Block even on non-blocking fd's >> Migration commands >> Return path: Control commands >> Return path: Send responses from destination to source >> Return path: Source handling of return path >> qemu_loadvm errors and debug >> ram_debug_dump_bitmap: Dump a migration bitmap as text >> Rework loadvm path for subloops >> Add migration-capability boolean for postcopy-ram. >> Add wrappers and handlers for sending/receiving the postcopy-ram >> migration messages. >> QEMU_VM_CMD_PACKAGED: Send a packaged chunk of migration stream >> migrate_init: Call from savevm >> Allow savevm handlers to state whether they could go into postcopy >> postcopy: OS support test >> migrate_start_postcopy: Command to trigger transition to postcopy >> MIG_STATE_POSTCOPY_ACTIVE: Add new migration state >> qemu_savevm_state_complete: Postcopy changes >> Postcopy page-map-incoming (PMI) structure >> Postcopy: Maintain sentmap and calculate discard >> postcopy: Incoming initialisation >> postcopy: ram_enable_notify to switch on userfault >> Postcopy: Postcopy startup in migration thread >> Postcopy: Create a fault handler thread before marking the ram as >> userfault >> Page request: Add MIG_RPCOMM_REQPAGES reverse command >> Page request: Process incoming page request >> Page request: Consume pages off the post-copy queue >> Add assertion to check migration_dirty_pages >> postcopy_ram.c: place_page and helpers >> Postcopy: Use helpers to map pages during migration >> qemu_ram_block_from_host >> Don't sync dirty bitmaps in postcopy >> Host page!=target page: Cleanup bitmaps >> Postcopy; Handle userfault requests >> Start up a postcopy/listener thread ready for incoming page data >> postcopy: Wire up loadvm_postcopy_ram_handle_{run,end} commands >> End of migration for postcopy >> >> Makefile.objs | 2 +- >> arch_init.c | 739 +++++++++++++++++++++++++-- >> docs/migration.txt | 189 +++++++ >> exec.c | 76 ++- >> hmp-commands.hx | 15 + >> hmp.c | 7 + >> hmp.h | 1 + >> include/exec/cpu-common.h | 8 +- >> include/migration/migration.h | 130 +++++ >> include/migration/postcopy-ram.h | 106 ++++ >> include/migration/qemu-file.h | 47 ++ >> include/migration/vmstate.h | 2 +- >> include/qemu/sockets.h | 1 + >> include/qemu/typedefs.h | 9 +- >> include/sysemu/sysemu.h | 43 +- >> migration-fd.c | 24 +- >> migration-rdma.c | 4 +- >> migration.c | 693 +++++++++++++++++++++++++- >> postcopy-ram.c | 1016 >> ++++++++++++++++++++++++++++++++++++++ >> qapi-schema.json | 14 +- >> qemu-file.c | 598 +++++++++++++++++++++- >> qmp-commands.hx | 19 + >> savevm.c | 881 +++++++++++++++++++++++++++++++-- >> tests/Makefile | 2 +- >> tests/test-vmstate.c | 74 +-- >> util/qemu-sockets.c | 28 ++ >> 26 files changed, 4550 insertions(+), 178 deletions(-) >> create mode 100644 include/migration/postcopy-ram.h >> create mode 100644 postcopy-ram.c >> >> -- >> 1.9.3 >> >> > -- > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
