Add a helper migration_get_switchover_bw() to return an estimate of switchover bandwidth. Use it to simplify the current code.
This will be used in later to remove expected_downtime. When at it, remove two qatomic_read() to shrink the lines because atomic ops are not needed when it's always the same thread who does the updates. Reviewed-by: Juraj Marcin <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Peter Xu <[email protected]> --- migration/migration.c | 48 +++++++++++++++++++++---------------------- 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index 8abc7e0327..4e19fe3409 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -984,6 +984,21 @@ void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value) migrate_send_rp_message(mis, MIG_RP_MSG_RESUME_ACK, sizeof(buf), &buf); } +/* + * Returns the estimated switchover bandwidth (unit: bytes / seconds) + */ +static double migration_get_switchover_bw(MigrationState *s) +{ + uint64_t switchover_bw = migrate_avail_switchover_bandwidth(); + + if (switchover_bw) { + /* If user specified, prioritize this value and don't estimate */ + return (double)switchover_bw; + } + + return s->mbps / 8 * 1000 * 1000; +} + bool migration_is_running(void) { MigrationState *s = current_migration; @@ -3130,37 +3145,22 @@ static void migration_update_counters(MigrationState *s, { uint64_t transferred, transferred_pages, time_spent; uint64_t current_bytes; /* bytes transferred since the beginning */ - uint64_t switchover_bw; - /* Expected bandwidth when switching over to destination QEMU */ - double expected_bw_per_ms; - double bandwidth; + double switchover_bw_per_ms; if (current_time < s->iteration_start_time + BUFFER_DELAY) { return; } - switchover_bw = migrate_avail_switchover_bandwidth(); current_bytes = migration_transferred_bytes(); transferred = current_bytes - s->iteration_initial_bytes; time_spent = current_time - s->iteration_start_time; - bandwidth = (double)transferred / time_spent; - - if (switchover_bw) { - /* - * If the user specified a switchover bandwidth, let's trust the - * user so that can be more accurate than what we estimated. - */ - expected_bw_per_ms = (double)switchover_bw / 1000; - } else { - /* If the user doesn't specify bandwidth, we use the estimated */ - expected_bw_per_ms = bandwidth; - } - - s->threshold_size = expected_bw_per_ms * migrate_downtime_limit(); - s->mbps = (((double) transferred * 8.0) / ((double) time_spent / 1000.0)) / 1000.0 / 1000.0; + /* NOTE: only update this after bandwidth (s->mbps) updated */ + switchover_bw_per_ms = migration_get_switchover_bw(s) / 1000; + s->threshold_size = switchover_bw_per_ms * migrate_downtime_limit(); + transferred_pages = ram_get_total_transferred_pages() - s->iteration_initial_pages; s->pages_per_second = (double) transferred_pages / @@ -3170,10 +3170,9 @@ static void migration_update_counters(MigrationState *s, * if we haven't sent anything, we don't want to * recalculate. 10000 is a small enough number for our purposes */ - if (qatomic_read(&mig_stats.dirty_pages_rate) && - transferred > 10000) { + if (mig_stats.dirty_pages_rate && transferred > 10000) { s->expected_downtime = - qatomic_read(&mig_stats.dirty_bytes_last_sync) / expected_bw_per_ms; + mig_stats.dirty_bytes_last_sync / switchover_bw_per_ms; } migration_rate_reset(); @@ -3182,7 +3181,8 @@ static void migration_update_counters(MigrationState *s, trace_migrate_transferred(transferred, time_spent, /* Both in unit bytes/ms */ - bandwidth, switchover_bw / 1000, + (uint64_t)s->mbps, + (uint64_t)switchover_bw_per_ms, s->threshold_size); } -- 2.53.0
