Method do_memory_migration

vmm/src/lib.rs:1349–1392

Performs the memory migration including multiple iterations. This includes: - initial memory - VM is running - multiple memory delta transmissions - VM is running - final memory iteration - VM is paused Stores the [finalized] [`MemoryMigrationContext`] in the provided [`OngoingMigrationContext`]. [finalized]: MemoryMigrationContext::finalize

(
        vm: &mut Vm,
        socket: &mut SocketStream,
        send_data_migration: &VmSendMigrationData,
        mem_send: &mut SendAdditionalConnections,
        ctx: &mut OngoingMigrationContext

    ///
    /// [finalized]: MemoryMigrationContext::finalize
    fn do_memory_migration(
        vm: &mut Vm,
        socket: &mut SocketStream,
        send_data_migration: &VmSendMigrationData,
        mem_send: &mut SendAdditionalConnections,
        ctx: &mut OngoingMigrationContext,
    ) -> result::Result<(), MigratableError> {
        let mut mem_ctx = MemoryMigrationContext::new();

        vm.start_dirty_log()?;
        let remaining = Self::do_memory_iterations(
            vm,
            socket,
            &mut mem_ctx,
            // We bind send_data_migration to the callback
            |ctx| Self::is_precopy_converged(ctx, send_data_migration),
            mem_send,
        )?;
        let downtime_begin = Instant::now();
        if vm.get_state() != VmState::Paused {
            vm.pause()?;
        }

        // Send last batch of dirty pages: final iteration
        {
            let iteration_begin = Instant::now();

            let mut final_table = vm.dirty_log()?;
            final_table.extend(remaining);

            mem_ctx.update_metrics_before_transfer(iteration_begin, &final_table);
            let transfer_begin = Instant::now();
            mem_send.send_memory(final_table, socket)?;
            let transfer_duration = transfer_begin.elapsed();
            mem_ctx.update_metrics_after_transfer(transfer_begin, transfer_duration);
            mem_ctx.iteration += 1;
        }
        mem_ctx.finalize();
        info!("Precopy complete: {mem_ctx}");
        ctx.set_vm_paused(downtime_begin, mem_ctx)
            .expect("migration context should transition to VmPaused after memory migration");

        Ok(())
    }

    /// Performs a migration including all its phases.
    fn send_migration(