* Peter Xu (pet...@redhat.com) wrote:
> This provides a way to start postcopy ASAP when migration starts. To do
> this, we need both:
>
> -global migration.x-postcopy-ram=on \
> -global migration.x-postcopy-fast=on
Can you explain why this is necessary? Both sides already know
they're doing a postcopy recovery don't they?
Dave
>
> Signed-off-by: Peter Xu <pet...@redhat.com>
> ---
> migration/migration.c | 9 ++++++++-
> migration/migration.h | 2 ++
> 2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 5b2602e..efee87e 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1936,6 +1936,11 @@ bool migrate_colo_enabled(void)
> return s->enabled_capabilities[MIGRATION_CAPABILITY_X_COLO];
> }
>
> +static bool postcopy_should_start(MigrationState *s)
> +{
> + return atomic_read(&s->start_postcopy) || s->start_postcopy_fast;
> +}
> +
> /*
> * Master migration thread on the source VM.
> * It drives the migration and pumps the data down the outgoing channel.
> @@ -2013,7 +2018,7 @@ static void *migration_thread(void *opaque)
> if (migrate_postcopy_ram() &&
> s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE &&
> pend_nonpost <= threshold_size &&
> - atomic_read(&s->start_postcopy)) {
> + postcopy_should_start(s)) {
>
> if (!postcopy_start(s, &old_vm_running)) {
> current_active_state =
> MIGRATION_STATUS_POSTCOPY_ACTIVE;
> @@ -2170,6 +2175,8 @@ static Property migration_properties[] = {
> send_configuration, true),
> DEFINE_PROP_BOOL("send-section-footer", MigrationState,
> send_section_footer, true),
> + DEFINE_PROP_BOOL("x-postcopy-fast", MigrationState,
> + start_postcopy_fast, false),
>
> /* Migration parameters */
> DEFINE_PROP_INT64("x-compress-level", MigrationState,
> diff --git a/migration/migration.h b/migration/migration.h
> index 70e3094..e902bae 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -113,6 +113,8 @@ struct MigrationState
>
> /* Flag set once the migration has been asked to enter postcopy */
> bool start_postcopy;
> + /* Set the flag if we want to start postcopy ASAP when migration starts
> */
> + bool start_postcopy_fast;
> /* Flag set after postcopy has sent the device state */
> bool postcopy_after_devices;
>
> --
> 2.7.4
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
