linux.git/include/net/netns/ipv4.h, branch v5.13

netfilter: remove all xt_table anchors from struct net

2021-04-26T01:20:47+00:00

No longer needed, table pointer arg is now passed via netfilter core.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

tcp: convert tcp_comp_sack_nr sysctl to u8

2021-03-31T21:48:20+00:00

tcp_comp_sack_nr max value was already 255.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv4: convert igmp_link_local_mcast_reports sysctl to u8

2021-03-31T21:48:20+00:00

This sysctl is a bool, can use less storage.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv4: convert fib_multipath_{use_neigh|hash_policy} sysctls to u8

2021-03-31T21:48:20+00:00

Make room for better packing of netns_ipv4

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv4: convert udp_l3mdev_accept sysctl to u8

2021-03-31T21:48:20+00:00

Reduce footprint of sysctls.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv4: convert fib_notify_on_flag_change sysctl to u8

2021-03-31T21:48:19+00:00

Reduce footprint of sysctls.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: shrink netns_ipv4 by another cache line

2021-03-31T21:48:19+00:00

By shuffling around some fields to remove 8 bytes of hole,
we can save one cache line.

pahole result before/after the patch :

/* size: 768, cachelines: 12, members: 139 */
/* sum members: 673, holes: 11, sum holes: 39 */
/* padding: 56 */
/* paddings: 2, sum paddings: 7 */
/* forced alignments: 1 */

->

/* size: 704, cachelines: 11, members: 139 */
/* sum members: 673, holes: 10, sum holes: 31 */
/* paddings: 2, sum paddings: 7 */
/* forced alignments: 1 */

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: shrink inet_timewait_death_row by 48 bytes

2021-03-31T21:48:19+00:00

struct inet_timewait_death_row uses two cache lines, because we want
tw_count to use a full cache line to avoid false sharing.

Rework its definition and placement in netns_ipv4 so that:

1) We add 60 bytes of padding after tw_count to avoid
  false sharing, knowing that tcp_death_row will
  have ____cacheline_aligned_in_smp attribute.

2) We do not risk padding before tcp_death_row, because
  we move it at the beginning of netns_ipv4, even if new
 fields are added later.

3) We do not waste 48 bytes of padding after it.

Note that I have not changed dccp.

pahole result for struct netns_ipv4 before/after the patch :

/* size: 832, cachelines: 13, members: 139 */
/* sum members: 721, holes: 12, sum holes: 95 */
/* padding: 16 */
/* paddings: 2, sum paddings: 55 */

->

/* size: 768, cachelines: 12, members: 139 */
/* sum members: 673, holes: 11, sum holes: 39 */
/* padding: 56 */
/* paddings: 2, sum paddings: 7 */
/* forced alignments: 1 */

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: add sysctl for enabling RFC 8335 PROBE messages

2021-03-30T20:29:39+00:00

Section 8 of RFC 8335 specifies potential security concerns of
responding to PROBE requests, and states that nodes that support PROBE
functionality MUST be able to enable/disable responses and that
responses MUST be disabled by default

Signed-off-by: Andreas Roeseler 
Signed-off-by: David S. Miller

tcp: convert elligible sysctls to u8

2021-03-26T00:39:33+00:00

Many tcp sysctls are either bools or small ints that can fit into u8.

Reducing space taken by sysctls can save few cache line misses
when sending/receiving data while cpu caches are empty,
for example after cpu idle period.

This is hard to measure with typical network performance tests,
but after this patch, struct netns_ipv4 has shrunk
by three cache lines.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller