On Wed, Feb 17, 2021 at 8:34 AM Gaetan Rivet <[email protected]> wrote:
>
> The current rate limit is set to allow other threads to update the
> connections when applicable. This was valid when taking the 'ct_lock'
> was needed with a global critical section.
>
> Now that the size of the critical section for 'ct_lock' is reduced, it
> is not necessary to rate limit calls to ct_sweep() anymore.
>
> Signed-off-by: Gaetan Rivet <[email protected]>
> Reviewed-by: Eli Britstein <[email protected]>
> ---
> lib/conntrack.c | 24 +++++++-----------------
> 1 file changed, 7 insertions(+), 17 deletions(-)
>
> diff --git a/lib/conntrack.c b/lib/conntrack.c
> index 71f79a790..1b21b79bd 100644
> --- a/lib/conntrack.c
> +++ b/lib/conntrack.c
> @@ -1602,20 +1602,12 @@ conntrack_clean(struct conntrack *ct, long long now)
> * there is an actual connection that expires, or because a new connection
> * might be created with the minimum timeout).
> *
> - * The logic below has two goals:
> - *
> - * - We want to reduce the number of wakeups and batch connection cleanup
> - * when the load is not very high. CT_CLEAN_INTERVAL ensures that if we
> - * are coping with the current cleanup tasks, then we wait at least
> - * 5 seconds to do further cleanup.
> - *
> - * - We don't want to keep the map locked too long, as we might prevent
> - * traffic from flowing. CT_CLEAN_MIN_INTERVAL ensures that if cleanup is
> - * behind, there is at least some 200ms blocks of time when the map will be
> - * left alone, so the datapath can operate unhindered.
> + * We want to reduce the number of wakeups and batch connection cleanup
> + * when the load is not very high. CT_CLEAN_INTERVAL ensures that if we
> + * are coping with the current cleanup tasks, then we wait at least
> + * 5 seconds to do further cleanup.
> */
IIUC, it's either wait for next 5-second interval, or keep cleaning when behind.
It depends on how fine grained people program the timeout value.
If users program s.t like 2-second, probably in reality it takes longer
to timeout.
William
> #define CT_CLEAN_INTERVAL 5000 /* 5 seconds */
> -#define CT_CLEAN_MIN_INTERVAL 200 /* 0.2 seconds */
>
> static void *
> clean_thread_main(void *f_)
> @@ -1627,12 +1619,10 @@ clean_thread_main(void *f_)
> long long now = time_msec();
> next_wake = conntrack_clean(ct, now);
>
> - if (next_wake < now) {
> - poll_immediate_wake();
> - } else if (next_wake < now + CT_CLEAN_MIN_INTERVAL) {
> - poll_timer_wait_until(now + CT_CLEAN_MIN_INTERVAL);
> + if (next_wake > now) {
> + poll_timer_wait_until(MIN(next_wake, now + CT_CLEAN_INTERVAL));
> } else {
> - poll_timer_wait_until(MAX(next_wake, now + CT_CLEAN_INTERVAL));
> + poll_immediate_wake();
> }
> latch_wait(&ct->clean_thread_exit);
> poll_block();
> --
> 2.30.0
>
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