"Dr. David Alan Gilbert (git)" <dgilb...@redhat.com> wrote:
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> userfaultfd is a Linux syscall that gives an fd that receives a stream
> of notifications of accesses to pages registered with it and allows
> the program to acknowledge those stalls and tell the accessing
> thread to carry on.
>
> We convert the requests from the kernel into messages back to the
> source asking for the pages.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> @@ -274,15 +276,41 @@ int postcopy_ram_incoming_init(MigrationIncomingState
> *mis, size_t ram_pages)
> */
> int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
> {
> - /* TODO: Join the fault thread once we're sure it will exit */
> - if (qemu_ram_foreach_block(cleanup_area, mis)) {
> - return -1;
> + trace_postcopy_ram_incoming_cleanup_entry();
> +
> + if (mis->have_fault_thread) {
> + uint64_t tmp64;
> +
> + if (qemu_ram_foreach_block(cleanup_area, mis)) {
> + return -1;
> + }
> + /*
> + * Tell the fault_thread to exit, it's an eventfd that should
> + * currently be at 0, we're going to inc it to 1
> + */
> + tmp64 = 1;
> + if (write(mis->userfault_quit_fd, &tmp64, 8) == 8) {
> + trace_postcopy_ram_incoming_cleanup_join();
> + qemu_thread_join(&mis->fault_thread);
> + } else {
> + /* Not much we can do here, but may as well report it */
> + error_report("%s: incing userfault_quit_fd: %s", __func__,
> + strerror(errno));
"incing"???
