* zhanghailiang (zhang.zhanghaili...@huawei.com) wrote:
> We can migrate some dirty pages during the gap of checkpointing,
> by this way, we can reduce the amount of ram migrated during checkpointing.
>
> Signed-off-by: zhanghailiang
> ---
> migration/colo.c | 73 --
> migration/migration.h | 1 +
> migration/trace-events | 1 +
> qapi/migration.json| 4 ++-
> 4 files changed, 75 insertions(+), 4 deletions(-)
>
> diff --git a/migration/colo.c b/migration/colo.c
> index 44942c4e23..c36d94072f 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -47,6 +47,13 @@ static COLOMode last_colo_mode;
>
> #define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
>
> +#define DEFAULT_RAM_PENDING_CHECK 1000
> +
> +/* should be calculated by bandwidth and max downtime ? */
> +#define THRESHOLD_PENDING_SIZE (100 * 1024 * 1024UL)
In the last version I asked to change these two values to parameters.
Dave
> +static int checkpoint_request;
> +
> bool migration_in_colo_state(void)
> {
> MigrationState *s = migrate_get_current();
> @@ -517,6 +524,20 @@ static void colo_compare_notify_checkpoint(Notifier
> *notifier, void *data)
> colo_checkpoint_notify(data);
> }
>
> +static bool colo_need_migrate_ram_background(MigrationState *s)
> +{
> +uint64_t pending_size, pend_pre, pend_compat, pend_post;
> +int64_t max_size = THRESHOLD_PENDING_SIZE;
> +
> +qemu_savevm_state_pending(s->to_dst_file, max_size, &pend_pre,
> + &pend_compat, &pend_post);
> +pending_size = pend_pre + pend_compat + pend_post;
> +
> +trace_colo_need_migrate_ram_background(pending_size);
> +return (pending_size >= max_size);
> +}
> +
> +
> static void colo_process_checkpoint(MigrationState *s)
> {
> QIOChannelBuffer *bioc;
> @@ -572,6 +593,8 @@ static void colo_process_checkpoint(MigrationState *s)
>
> timer_mod(s->colo_delay_timer,
> current_time + s->parameters.x_checkpoint_delay);
> +timer_mod(s->pending_ram_check_timer,
> +current_time + DEFAULT_RAM_PENDING_CHECK);
>
> while (s->state == MIGRATION_STATUS_COLO) {
> if (failover_get_state() != FAILOVER_STATUS_NONE) {
> @@ -584,9 +607,30 @@ static void colo_process_checkpoint(MigrationState *s)
> if (s->state != MIGRATION_STATUS_COLO) {
> goto out;
> }
> -ret = colo_do_checkpoint_transaction(s, bioc, fb);
> -if (ret < 0) {
> -goto out;
> +if (atomic_xchg(&checkpoint_request, 0)) {
> +/* start a colo checkpoint */
> +ret = colo_do_checkpoint_transaction(s, bioc, fb);
> +if (ret < 0) {
> +goto out;
> +}
> +} else {
> +if (colo_need_migrate_ram_background(s)) {
> +colo_send_message(s->to_dst_file,
> + COLO_MESSAGE_MIGRATE_RAM_BACKGROUND,
> + &local_err);
> +if (local_err) {
> +goto out;
> +}
> +
> +qemu_savevm_state_iterate(s->to_dst_file, false);
> +qemu_put_byte(s->to_dst_file, QEMU_VM_EOF);
> +ret = qemu_file_get_error(s->to_dst_file);
> +if (ret < 0) {
> +error_setg_errno(&local_err, -ret,
> +"Failed to send dirty pages backgroud");
> +goto out;
> +}
> +}
> }
> }
>
> @@ -627,6 +671,8 @@ out:
> colo_compare_unregister_notifier(&packets_compare_notifier);
> timer_del(s->colo_delay_timer);
> timer_free(s->colo_delay_timer);
> +timer_del(s->pending_ram_check_timer);
> +timer_free(s->pending_ram_check_timer);
> qemu_sem_destroy(&s->colo_checkpoint_sem);
>
> /*
> @@ -644,6 +690,7 @@ void colo_checkpoint_notify(void *opaque)
> MigrationState *s = opaque;
> int64_t next_notify_time;
>
> +atomic_inc(&checkpoint_request);
> qemu_sem_post(&s->colo_checkpoint_sem);
> s->colo_checkpoint_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> next_notify_time = s->colo_checkpoint_time +
> @@ -651,6 +698,19 @@ void colo_checkpoint_notify(void *opaque)
> timer_mod(s->colo_delay_timer, next_notify_time);
> }
>
> +static void colo_pending_ram_check_notify(void *opaque)
> +{
> +int64_t next_notify_time;
> +MigrationState *s = opaque;
> +
> +if (migration_in_colo_state()) {
> +next_notify_time = DEFAULT_RAM_PENDING_CHECK +
> + qemu_clock_get_ms(QEMU_CLOCK_HOST);
> +timer_mod(s->pending_ram_check_timer, next_notify_time);
> +qemu_sem_post(&s->colo_checkpoint_sem);
> +}
> +}
> +
> void migrate_start_colo_process(MigrationState *s)
> {
> qemu_mutex_unlock_iothread();
> @@ -658,6 +718,8 @@ void migrate_start_colo_process(MigrationState *s)
> s->colo_delay_timer =
