Previously we slept for a minimum of 200ms after each cleaning run, even if we did clean the majority of entries. This originally came from the requirement that we need to take the whole conntrack lock to cleanup connections and are therefor limited in the progress we can still make when inserting.
However with the now implemented locks per zone and the batching this is no longer needed. In addition before we could do partion zone cleanings we always cleaned a full zone. This meant that a single high load zone would still be cleaned quite fast. Signed-off-by: Felix Huettner <[email protected]> --- Notes: v4->v5: * added news and coverage counter * fixed busylooping if n_conn_limit < 640 NEWS | 8 ++++++++ lib/conntrack.c | 24 ++++++++++++++++++++---- 2 files changed, 28 insertions(+), 4 deletions(-) diff --git a/NEWS b/NEWS index de1a030ad..4d6d05791 100644 --- a/NEWS +++ b/NEWS @@ -1,5 +1,13 @@ Post-v4.0.0 -------------------- + - Userspace datapath: + * The conntrack cleanup thread will now continue cleaning if more than 10% + of all checked entries have been deleted in the past iteration. This + will ensure that old entries are removed faster in high churn + situations. The coverage counter conntrack_clean_fast_wakeup has been + added for such events. + * Improved multi-thread multi-zone scalability of the userspace + connection tracking. v4.0.0 - 17 Aug 2026 diff --git a/lib/conntrack.c b/lib/conntrack.c index 0c91d5dc1..0f48eb649 100644 --- a/lib/conntrack.c +++ b/lib/conntrack.c @@ -57,6 +57,7 @@ COVERAGE_DEFINE(conntrack_zone_full); COVERAGE_DEFINE(conntrack_remove); COVERAGE_DEFINE(conntrack_insert); COVERAGE_DEFINE(conntrack_maybe_not_found); +COVERAGE_DEFINE(conntrack_clean_fast_wakeup); struct conn_lookup_ctx { struct conn_key key; @@ -1534,7 +1535,8 @@ ct_sweep_buf(struct conntrack *ct, uint16_t zone, static bool ct_sweep_zone(struct conntrack *ct, uint16_t zone, long long now, - size_t *cleaned_count, size_t *conn_count, size_t limit, + size_t *cleaned_count, size_t *conn_count, + long long *min_expiration, size_t limit, struct cmap_position **current_position) OVS_NO_THREAD_SAFETY_ANALYSIS { @@ -1586,6 +1588,8 @@ ct_sweep_zone(struct conntrack *ct, uint16_t zone, long long now, if (now >= expiration) { conn_buf[n_conn_buf++] = conn; (*cleaned_count)++; + } else { + *min_expiration = MIN(*min_expiration, expiration); } if (n_conn_buf == CONN_SWEEP_BUF_SIZE) { @@ -1608,6 +1612,7 @@ static long long conntrack_clean(struct conntrack *ct, long long now) { long long next_wakeup = now + conntrack_get_sweep_interval(ct); + long long min_expiration = LLONG_MAX; unsigned int n_conn_limit, i; size_t clean_end, count = 0; size_t total_cleaned = 0; @@ -1621,7 +1626,8 @@ conntrack_clean(struct conntrack *ct, long long now) size_t cleaned = 0; zone_finished = ct_sweep_zone(ct, ct->current_clean_zone, now, &cleaned, - &zone_count, clean_end - count, + &zone_count, &min_expiration, + clean_end - count, &ct->current_clean_position); total_cleaned += cleaned; @@ -1641,6 +1647,17 @@ conntrack_clean(struct conntrack *ct, long long now) " entries in %lld msec", total_cleaned, count, time_msec() - now); + /* If we did clean more than 10% of our connection limit we assume that + * if we would continue we would also find a lot of connections to clean. + * In this case we want to rather continue immediately to ensure we get + * the connections removed in a high load situation. */ + if (total_cleaned > (clean_end / 10)) { + COVERAGE_INC(conntrack_clean_fast_wakeup); + next_wakeup = 0; + } else { + next_wakeup = MIN(next_wakeup, min_expiration); + } + return next_wakeup; } @@ -1648,7 +1665,6 @@ conntrack_clean(struct conntrack *ct, long long now) * * We must call conntrack_clean() periodically. conntrack_clean() return * value gives an hint on when the next cleanup must be done. */ -#define CT_CLEAN_MIN_INTERVAL_MS 200 static void * clean_thread_main(void *f_) @@ -1662,7 +1678,7 @@ clean_thread_main(void *f_) next_wake = conntrack_clean(ct, now); if (next_wake < now) { - poll_timer_wait_until(now + CT_CLEAN_MIN_INTERVAL_MS); + poll_immediate_wake(); } else { poll_timer_wait_until(next_wake); } -- 2.43.0 _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
