Merge branch 'mlxsw-Improve-IPv6-route-insertion-rate'

Ido Schimmel says:

====================
mlxsw: Improve IPv6 route insertion rate

Unlike IPv4, an IPv6 multipath route in the kernel is composed from
multiple sibling routes, each representing a single nexthop.

Therefore, an addition of a multipath route with N nexthops translates
to N in-kernel notifications. This is inefficient for device drivers
that need to program the route to the underlying device. Each time a new
nexthop is appended, a new nexthop group needs to be constructed and the
old one deleted.

This patchset improves the situation by sending a single notification
for a multipath route addition / deletion instead of one per-nexthop.
When adding thousands of multipath routes with 16 nexthops, I measured
an improvement of about x10 in the insertion rate.

Patches #1-#3 add a flag that indicates that in-kernel notifications
need to be suppressed and extend the IPv6 FIB notification info with
information about the number of sibling routes that are being notified.

Patches #4-#5 adjust the two current listeners to these notifications to
ignore notifications about IPv6 multipath routes.

Patches #6-#7 adds add / delete notifications for IPv6 multipath routes.

Patches #8-#14 do the same for mlxsw.

Patch #15 finally removes the limitations added in patches #4-#5 and
stops the kernel from sending a notification for each added / deleted
nexthop.

Patch #16 adds test cases.

v2 (David Ahern):
* Remove patch adjusting netdevsim to consume resources for each
  fib6_info. Instead, consume one resource for the entire multipath
  route
* Remove 'multipath_rt' usage in patch #10
* Remove 'multipath_rt' from 'struct fib6_entry_notifier_info' in patch
  #15. The member is only removed in this patch to prevent drivers from
  processing multipath routes twice during the series
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 11 insertions, 1 deletions

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 1e92f1500b87..87331f2c4af0 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -377,6 +377,7 @@ typedef struct rt6_info *(*pol_lookup_t)(struct net *,
 struct fib6_entry_notifier_info {
 	struct fib_notifier_info info; /* must be first */
 	struct fib6_info *rt;
+	unsigned int nsiblings;
 };
 
 /*
@@ -450,6 +451,11 @@ int call_fib6_entry_notifiers(struct net *net,
 			      enum fib_event_type event_type,
 			      struct fib6_info *rt,
 			      struct netlink_ext_ack *extack);
+int call_fib6_multipath_entry_notifiers(struct net *net,
+					enum fib_event_type event_type,
+					struct fib6_info *rt,
+					unsigned int nsiblings,
+					struct netlink_ext_ack *extack);
 void fib6_rt_update(struct net *net, struct fib6_info *rt,
 		    struct nl_info *info);
 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
diff --git a/include/net/netlink.h b/include/net/netlink.h
index 28ece67f5312..e4650e5b64a1 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -378,13 +378,17 @@ struct nla_policy {
 /**
  * struct nl_info - netlink source information
  * @nlh: Netlink message header of original request
+ * @nl_net: Network namespace
  * @portid: Netlink PORTID of requesting application
+ * @skip_notify: Skip netlink notifications to user space
+ * @skip_notify_kernel: Skip selected in-kernel notifications
  */
 struct nl_info {
 	struct nlmsghdr		*nlh;
 	struct net		*nl_net;
 	u32			portid;
-	bool			skip_notify;
+	u8			skip_notify:1,
+				skip_notify_kernel:1;
 };
 
 /**