@@ -141,6 +141,9 @@ nl_ct_dump_start(struct nl_ct_dump_state **statep, const uint16_t *zone,
nl_msg_put_nfgenmsg(&state->buf, 0, AF_UNSPEC, NFNL_SUBSYS_CTNETLINK,
IPCTNL_MSG_CT_GET, NLM_F_REQUEST);
+ if (zone) {
+ nl_msg_put_be16(&state->buf, CTA_ZONE, htons(*zone));
+ }
nl_dump_start(&state->dump, NETLINK_NETFILTER, &state->buf);
ofpbuf_clear(&state->buf);
@@ -263,11 +266,9 @@ out:
return err;
}
-#ifdef _WIN32
-int
-nl_ct_flush_zone(uint16_t flush_zone)
+static int
+nl_ct_flush_zone_with_cta_zone(uint16_t flush_zone)
{
- /* Windows can flush a specific zone */
struct ofpbuf buf;
int err;
@@ -282,24 +283,63 @@ nl_ct_flush_zone(uint16_t flush_zone)
return err;
}
+
+#ifdef _WIN32
+int
+nl_ct_flush_zone(uint16_t flush_zone)
+{
+ return nl_ct_flush_zone_with_cta_zone(flush_zone);
+}
#else
+
+static bool
+netlink_flush_supports_zone(void)
+{
+ static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+ static bool supported = false;
+
+ if (ovsthread_once_start(&once)) {
+ if (ovs_kernel_is_version_or_newer(6, 8)) {
+ supported = true;
+ } else {
+ VLOG_INFO("disabling conntrack flush by zone. "
+ "Not supported in Linux kernel");
+ }
+ ovsthread_once_done(&once);
+ }
+ return supported;
+}
+
int
nl_ct_flush_zone(uint16_t flush_zone)
{
- /* Apparently, there's no netlink interface to flush a specific zone.
+ /* In older kernels, there was no netlink interface to flush a specific
+ * conntrack zone.
* This code dumps every connection, checks the zone and eventually
* delete the entry.
+ * In newer kernels there is the option to specify a zone for filtering
+ * during dumps. Older kernels ignore this option. We set it here in the
+ * hope we only get relevant entries back, but fall back to filtering here
+ * to keep compatibility.
*
- * This is race-prone, but it is better than using shell scripts. */
+ * This is race-prone, but it is better than using shell scripts.
+ *
+ * Additionally newer kernels also support flushing a zone without listing
+ * it first. */
struct nl_dump dump;
struct ofpbuf buf, reply, delete;
+ if (netlink_flush_supports_zone()) {
+ return nl_ct_flush_zone_with_cta_zone(flush_zone);
+ }
+
ofpbuf_init(&buf, NL_DUMP_BUFSIZE);
ofpbuf_init(&delete, NL_DUMP_BUFSIZE);
nl_msg_put_nfgenmsg(&buf, 0, AF_UNSPEC, NFNL_SUBSYS_CTNETLINK,
IPCTNL_MSG_CT_GET, NLM_F_REQUEST);
+ nl_msg_put_be16(&buf, CTA_ZONE, htons(flush_zone));
nl_dump_start(&dump, NETLINK_NETFILTER, &buf);
ofpbuf_clear(&buf);
@@ -3376,6 +3376,14 @@ AT_CHECK([ovs-appctl dpctl/dump-conntrack | FORMAT_CT(10.1.1.4)], [0], [dnl
tcp,orig=(src=10.1.1.3,dst=10.1.1.4,sport=<cleared>,dport=<cleared>),reply=(src=10.1.1.4,dst=10.1.1.3,sport=<cleared>,dport=<cleared>),zone=2,protoinfo=(state=<cleared>)
])
+dnl flushing one zone should leave the others intact
+AT_CHECK([ovs-appctl dpctl/flush-conntrack zone=2])
+AT_CHECK([ovs-appctl dpctl/dump-conntrack zone=1 | FORMAT_CT(10.1.1.2)], [0], [dnl
+tcp,orig=(src=10.1.1.1,dst=10.1.1.2,sport=<cleared>,dport=<cleared>),reply=(src=10.1.1.2,dst=10.1.1.1,sport=<cleared>,dport=<cleared>),zone=1,protoinfo=(state=<cleared>)
+])
+AT_CHECK([ovs-appctl dpctl/dump-conntrack zone=2 | FORMAT_CT(10.1.1.4)], [0], [dnl
+])
+
OVS_TRAFFIC_VSWITCHD_STOP
AT_CLEANUP
Previously the kernel did not provide a netlink interface to flush/list only conntrack entries matching a specific zone. With [1] and [2] it is now possible to flush and list conntrack entries filtered by zone. Older kernels not yet supporting this feature will ignore the filter. For the list request that means just returning all entries (which we can then filter in userspace as before). For the flush request that means deleting all conntrack entries. The implementation is now identical to the windows one, so we combine them. These significantly improves the performance of flushing conntrack zones when the conntrack table is large. Since flushing a conntrack zone is normally triggered via an openflow command it blocks the main ovs thread and thereby also blocks new flows from being applied. Using this new feature we can reduce the flushing time for zones by around 93%. In combination with OVN the creation of a Logical_Router (which causes the flushing of a ct zone) could block other operations, e.g. the failover of Logical_Routers (as they cause new flows to be created). This is visible from a user perspective as a ovn-controller that is idle (as it waits for vswitchd) and vswitchd reporting: "blocked 1000 ms waiting for main to quiesce" (potentially with ever increasing times). The following performance tests where run in a qemu vm with 500.000 conntrack entries distributed evenly over 500 ct zones using `ovstest test-netlink-conntrack flush zone=<zoneid>`. | flush zone with 1000 entries | flush zone with no entry | +---------------------+----------+---------------------+----------| | with the patch | without | with the patch | without | +----------+----------+----------+----------+----------+----------| | v6.8-rc4 | v6.7.1 | v6.8-rc4 | v6.8-rc4 | v6.7.1 | v6.8-rc4 | +---------+----------+----------+----------+----------+----------+----------| | Min | 0.260 | 3.946 | 3.497 | 0.228 | 3.462 | 3.212 | | Median | 0.319 | 4.237 | 4.349 | 0.298 | 4.460 | 4.010 | | 90%ile | 0.335 | 4.367 | 4.522 | 0.325 | 4.662 | 4.572 | | 99%ile | 0.348 | 4.495 | 4.773 | 0.340 | 4.931 | 6.003 | | Max | 0.362 | 4.543 | 5.054 | 0.348 | 5.390 | 6.396 | | Mean | 0.320 | 4.236 | 4.331 | 0.296 | 4.430 | 4.071 | | Total | 80.02 | 1058 | 1082 | 73.93 | 1107 | 1017 | [1]: https://github.com/torvalds/linux/commit/eff3c558bb7e61c41b53e4c8130e514a5a4df9ba [2]: https://github.com/torvalds/linux/commit/fa173a1b4e3fd1ab5451cbc57de6fc624c824b0a Co-Authored-By: Luca Czesla <luca.czesla@mail.schwarz> Signed-off-by: Luca Czesla <luca.czesla@mail.schwarz> Co-Authored-By: Max Lamprecht <max.lamprecht@mail.schwarz> Signed-off-by: Max Lamprecht <max.lamprecht@mail.schwarz> Signed-off-by: Felix Huettner <felix.huettner@mail.schwarz> --- v3->v4: - combine the flush logic with windows implementation v2->v3: - update description to include upstream fix (Thanks to Ilya for finding that issue) v1->v2: - fixed wrong signed-off-by lib/netlink-conntrack.c | 52 ++++++++++++++++++++++++++++++++++++----- tests/system-traffic.at | 8 +++++++ 2 files changed, 54 insertions(+), 6 deletions(-)