kernel/linux.git/include/net/hotdata.h, branch v6.19.11

net: add net.core.qdisc_max_burst

2026-01-13T09:12:11+00:00

In blamed commit, I added a check against the temporary queue built in __dev_xmit_skb(). Idea was to drop packets early, before any spinlock was acquired. if (unlikely(defer_count > READ_ONCE(q->limit))) { kfree_skb_reason(skb, SKB_DROP_REASON_QDISC_DROP); return NET_XMIT_DROP; } It turned out that HTB Qdisc has a zero q->limit. HTB limits packets on a per-class basis. Some of our tests became flaky. Add a new sysctl : net.core.qdisc_max_burst to control how many packets can be stored in the temporary lockless queue. Also add a new QDISC_BURST_DROP drop reason to better diagnose future issues. Thanks Neal ! Fixes: 100dfa74cad9 ("net: dev_queue_xmit() llist adoption") Reported-and-bisected-by: Neal Cardwell Signed-off-by: Eric Dumazet Reviewed-by: Neal Cardwell Link: https://patch.msgid.link/20260107104159.3669285-1-edumazet@google.com Signed-off-by: Paolo Abeni

net: add NUMA awareness to skb_attempt_defer_free()

2025-09-30T13:45:53+00:00

Instead of sharing sd->defer_list & sd->defer_count with many cpus, add one pair for each NUMA node. Signed-off-by: Eric Dumazet Reviewed-by: Jason Xing Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250928084934.3266948-4-edumazet@google.com Signed-off-by: Paolo Abeni

net: introduce per netns packet chains

2025-03-24T20:58:22+00:00

Currently network taps unbound to any interface are linked in the global ptype_all list, affecting the performance in all the network namespaces. Add per netns ptypes chains, so that in the mentioned case only the netns owning the packet socket(s) is affected. While at that drop the global ptype_all list: no in kernel user registers a tap on "any" type without specifying either the target device or the target namespace (and IMHO doing that would not make any sense). Note that this adds a conditional in the fast path (to check for per netns ptype_specific list) and increases the dataset size by a cacheline (owing the per netns lists). Reviewed-by: Sabrina Dubroca Signed-off-by: Paolo Abeni Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/ae405f98875ee87f8150c460ad162de7e466f8a7.1742494826.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski

net: move sysctl_mem_pcpu_rsv to net_hotdata

2024-05-01T01:46:52+00:00

sysctl_mem_pcpu_rsv is used in TCP fast path, move it to net_hodata for better cache locality. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240429134025.1233626-6-edumazet@google.com Signed-off-by: Jakub Kicinski

net: move sysctl_skb_defer_max to net_hotdata

2024-05-01T01:46:52+00:00

sysctl_skb_defer_max is used in TCP fast path, move it to net_hodata. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240429134025.1233626-3-edumazet@google.com Signed-off-by: Jakub Kicinski

net: move sysctl_max_skb_frags to net_hotdata

2024-05-01T01:46:52+00:00

sysctl_max_skb_frags is used in TCP and MPTCP fast paths, move it to net_hodata for better cache locality. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240429134025.1233626-2-edumazet@google.com Signed-off-by: Jakub Kicinski

net: move rps_sock_flow_table to net_hotdata

2024-03-08T05:12:43+00:00

rps_sock_flow_table and rps_cpu_mask are used in fast path. Move them to net_hotdata for better cache locality. Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240306160031.874438-19-edumazet@google.com Signed-off-by: Jakub Kicinski

ipv6: move tcp_ipv6_hash_secret and udp_ipv6_hash_secret to net_hotdata

2024-03-08T05:12:43+00:00

Use a 32bit hole in "struct net_offload" to store the remaining 32bit secrets used by TCPv6 and UDPv6. Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240306160031.874438-17-edumazet@google.com Signed-off-by: Jakub Kicinski

ipv6: move inet6_ehash_secret and udp6_ehash_secret into net_hotdata

2024-03-08T05:12:43+00:00

"struct inet6_protocol" has a 32bit hole in 32bit arches. Use it to store the 32bit secret used by UDP and TCP, to increase cache locality in rx path. Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240306160031.874438-16-edumazet@google.com Signed-off-by: Jakub Kicinski

inet: move inet_ehash_secret and udp_ehash_secret into net_hotdata

2024-03-08T05:12:43+00:00

"struct net_protocol" has a 32bit hole in 32bit arches. Use it to store the 32bit secret used by UDP and TCP, to increase cache locality in rx path. Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240306160031.874438-15-edumazet@google.com Signed-off-by: Jakub Kicinski