Bump the maximum number of labels for MPLS routes from 2 to 12. To keep memory consumption in check the labels array is moved to the end of mpls_nh and mpls_iptunnel_encap structs as a 0-sized array. Allocations use the maximum number of labels across all nexthops in a route for LSR and the number of labels configured for LWT.
The mpls_route layout is changed to: +----------------------+ | mpls_route | +----------------------+ | mpls_nh 0 | +----------------------+ | alignment padding | 4 bytes for odd number of labels; 0 for even +----------------------+ | via[rt_max_alen] 0 | +----------------------+ | alignment padding | via's aligned on sizeof(unsigned long) +----------------------+ | ... | Meaning the via follows its mpls_nh providing better locality as the number of labels increases. UDP_RR tests with namespaces shows no impact to a modest performance increase with this layout for 1 or 2 labels and 1 or 2 nexthops. The new limit is set to 12 to cover all currently known segment routing use cases. David Ahern (4): mpls: Convert number of nexthops to u8 net: mpls: change mpls_route layout net: mpls: bump maximum number of labels net: mpls: Increase max number of labels for lwt encap include/net/mpls_iptunnel.h | 4 +- net/mpls/af_mpls.c | 108 ++++++++++++++++++++++++++------------------ net/mpls/internal.h | 52 ++++++++++++++------- net/mpls/mpls_iptunnel.c | 13 ++++-- 4 files changed, 112 insertions(+), 65 deletions(-) -- 2.1.4
