[Qemu-devel] [PULL 51/57] Start up a postcopy/listener thread ready for incoming page data
From: "Dr. David Alan Gilbert" The loading of a device state (during postcopy) may access guest memory that's still on the source machine and thus might need a page fill; split off a separate thread that handles the incoming page data so that the original incoming migration code can finish off the device data. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- include/migration/migration.h | 4 +++ migration/migration.c | 6 migration/savevm.c| 79 ++- trace-events | 2 ++ 4 files changed, 90 insertions(+), 1 deletion(-) diff --git a/include/migration/migration.h b/include/migration/migration.h index 329d535..fd018b7 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -93,6 +93,10 @@ struct MigrationIncomingState { QemuThread fault_thread; QemuSemaphore fault_thread_sem; +bool have_listen_thread; +QemuThread listen_thread; +QemuSemaphore listen_thread_sem; + /* For the kernel to send us notifications */ int userfault_fd; /* To tell the fault_thread to quit */ diff --git a/migration/migration.c b/migration/migration.c index a12ba15..180103a 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1441,6 +1441,12 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) goto fail; } +/* + * Make sure the receiver can get incoming pages before we send the rest + * of the state + */ +qemu_savevm_send_postcopy_listen(fb); + qemu_savevm_state_complete_precopy(fb); qemu_savevm_send_ping(fb, 3); diff --git a/migration/savevm.c b/migration/savevm.c index 9794945..51c3fb1 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -1380,6 +1380,65 @@ static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis, return 0; } +/* + * Triggered by a postcopy_listen command; this thread takes over reading + * the input stream, leaving the main thread free to carry on loading the rest + * of the device state (from RAM). + * (TODO:This could do with being in a postcopy file - but there again it's + * just another input loop, not that postcopy specific) + */ +static void *postcopy_ram_listen_thread(void *opaque) +{ +QEMUFile *f = opaque; +MigrationIncomingState *mis = migration_incoming_get_current(); +int load_res; + +qemu_sem_post(&mis->listen_thread_sem); +trace_postcopy_ram_listen_thread_start(); + +/* + * Because we're a thread and not a coroutine we can't yield + * in qemu_file, and thus we must be blocking now. + */ +qemu_file_set_blocking(f, true); +load_res = qemu_loadvm_state_main(f, mis); +/* And non-blocking again so we don't block in any cleanup */ +qemu_file_set_blocking(f, false); + +trace_postcopy_ram_listen_thread_exit(); +if (load_res < 0) { +error_report("%s: loadvm failed: %d", __func__, load_res); +qemu_file_set_error(f, load_res); +} else { +/* + * This looks good, but it's possible that the device loading in the + * main thread hasn't finished yet, and so we might not be in 'RUN' + * state yet; wait for the end of the main thread. + */ +qemu_event_wait(&mis->main_thread_load_event); +} +postcopy_ram_incoming_cleanup(mis); +/* + * If everything has worked fine, then the main thread has waited + * for us to start, and we're the last use of the mis. + * (If something broke then qemu will have to exit anyway since it's + * got a bad migration state). + */ +migration_incoming_state_destroy(); + +if (load_res < 0) { +/* + * If something went wrong then we have a bad state so exit; + * depending how far we got it might be possible at this point + * to leave the guest running and fire MCEs for pages that never + * arrived as a desperate recovery step. + */ +exit(EXIT_FAILURE); +} + +return NULL; +} + /* After this message we must be able to immediately receive postcopy data */ static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) { @@ -1399,7 +1458,20 @@ static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) return -1; } -/* TODO start up the postcopy listening thread */ +if (mis->have_listen_thread) { +error_report("CMD_POSTCOPY_RAM_LISTEN already has a listen thread"); +return -1; +} + +mis->have_listen_thread = true; +/* Start up the listening thread and wait for it to signal ready */ +qemu_sem_init(&mis->listen_thread_sem, 0); +qemu_thread_create(&mis->listen_thread, "postcopy/listen", + postcopy_ram_listen_thread, mis->from_src_file, + QEMU_THREAD_JOINABLE); +qemu_sem_wait(&mis->listen_thread_sem); +qemu_sem_destro
[Qemu-devel] [PULL 51/57] Start up a postcopy/listener thread ready for incoming page data
From: "Dr. David Alan Gilbert" The loading of a device state (during postcopy) may access guest memory that's still on the source machine and thus might need a page fill; split off a separate thread that handles the incoming page data so that the original incoming migration code can finish off the device data. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- include/migration/migration.h | 4 +++ migration/migration.c | 6 migration/savevm.c| 79 ++- trace-events | 2 ++ 4 files changed, 90 insertions(+), 1 deletion(-) diff --git a/include/migration/migration.h b/include/migration/migration.h index 329d535..fd018b7 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -93,6 +93,10 @@ struct MigrationIncomingState { QemuThread fault_thread; QemuSemaphore fault_thread_sem; +bool have_listen_thread; +QemuThread listen_thread; +QemuSemaphore listen_thread_sem; + /* For the kernel to send us notifications */ int userfault_fd; /* To tell the fault_thread to quit */ diff --git a/migration/migration.c b/migration/migration.c index 38d64ea..db3d2dd 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1441,6 +1441,12 @@ static int postcopy_start(MigrationState *ms, bool *old_vm_running) goto fail; } +/* + * Make sure the receiver can get incoming pages before we send the rest + * of the state + */ +qemu_savevm_send_postcopy_listen(fb); + qemu_savevm_state_complete_precopy(fb); qemu_savevm_send_ping(fb, 3); diff --git a/migration/savevm.c b/migration/savevm.c index 308b7d1..6ef9e62 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -1380,6 +1380,65 @@ static int loadvm_postcopy_ram_handle_discard(MigrationIncomingState *mis, return 0; } +/* + * Triggered by a postcopy_listen command; this thread takes over reading + * the input stream, leaving the main thread free to carry on loading the rest + * of the device state (from RAM). + * (TODO:This could do with being in a postcopy file - but there again it's + * just another input loop, not that postcopy specific) + */ +static void *postcopy_ram_listen_thread(void *opaque) +{ +QEMUFile *f = opaque; +MigrationIncomingState *mis = migration_incoming_get_current(); +int load_res; + +qemu_sem_post(&mis->listen_thread_sem); +trace_postcopy_ram_listen_thread_start(); + +/* + * Because we're a thread and not a coroutine we can't yield + * in qemu_file, and thus we must be blocking now. + */ +qemu_file_set_blocking(f, true); +load_res = qemu_loadvm_state_main(f, mis); +/* And non-blocking again so we don't block in any cleanup */ +qemu_file_set_blocking(f, false); + +trace_postcopy_ram_listen_thread_exit(); +if (load_res < 0) { +error_report("%s: loadvm failed: %d", __func__, load_res); +qemu_file_set_error(f, load_res); +} else { +/* + * This looks good, but it's possible that the device loading in the + * main thread hasn't finished yet, and so we might not be in 'RUN' + * state yet; wait for the end of the main thread. + */ +qemu_event_wait(&mis->main_thread_load_event); +} +postcopy_ram_incoming_cleanup(mis); +/* + * If everything has worked fine, then the main thread has waited + * for us to start, and we're the last use of the mis. + * (If something broke then qemu will have to exit anyway since it's + * got a bad migration state). + */ +migration_incoming_state_destroy(); + +if (load_res < 0) { +/* + * If something went wrong then we have a bad state so exit; + * depending how far we got it might be possible at this point + * to leave the guest running and fire MCEs for pages that never + * arrived as a desperate recovery step. + */ +exit(EXIT_FAILURE); +} + +return NULL; +} + /* After this message we must be able to immediately receive postcopy data */ static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) { @@ -1399,7 +1458,20 @@ static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) return -1; } -/* TODO start up the postcopy listening thread */ +if (mis->have_listen_thread) { +error_report("CMD_POSTCOPY_RAM_LISTEN already has a listen thread"); +return -1; +} + +mis->have_listen_thread = true; +/* Start up the listening thread and wait for it to signal ready */ +qemu_sem_init(&mis->listen_thread_sem, 0); +qemu_thread_create(&mis->listen_thread, "postcopy/listen", + postcopy_ram_listen_thread, mis->from_src_file, + QEMU_THREAD_JOINABLE); +qemu_sem_wait(&mis->listen_thread_sem); +qemu_sem_destro