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| author | Jakub Kicinski <kuba@kernel.org> | 2025-07-02 14:22:04 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-02 14:22:04 -0700 |
| commit | 8077b9a911d7cb0f606217f645d82c7b083ca238 (patch) | |
| tree | 7d57f406a870c95a827b3934c61a4d159d6d495a /net/unix/sysctl_net_unix.c | |
| parent | a8065af3346ebd7c76ebc113451fb3ba94cf7769 (diff) | |
| parent | e3d4825124bce0d1f72187fabcf972b7c0b6cb9b (diff) | |
Merge branch 'net-introduce-net_aligned_data'
Eric Dumazet says:
====================
net: introduce net_aligned_data
____cacheline_aligned_in_smp on small fields like
tcp_memory_allocated and udp_memory_allocated is not good enough.
It makes sure to put these fields at the start of a cache line,
but does not prevent the linker from using the cache line for other
fields, with potential performance impact.
nm -v vmlinux|egrep -5 "tcp_memory_allocated|udp_memory_allocated"
...
ffffffff83e35cc0 B tcp_memory_allocated
ffffffff83e35cc8 b __key.0
ffffffff83e35cc8 b __tcp_tx_delay_enabled.1
ffffffff83e35ce0 b tcp_orphan_timer
...
ffffffff849dddc0 B udp_memory_allocated
ffffffff849dddc8 B udp_encap_needed_key
ffffffff849dddd8 B udpv6_encap_needed_key
ffffffff849dddf0 b inetsw_lock
One solution is to move these sensitive fields to a structure,
so that the compiler is forced to add empty holes between each member.
nm -v vmlinux|egrep -2 "tcp_memory_allocated|udp_memory_allocated|net_aligned_data"
ffffffff885af970 b mem_id_init
ffffffff885af980 b __key.0
ffffffff885af9c0 B net_aligned_data
ffffffff885afa80 B page_pool_mem_providers
ffffffff885afa90 b __key.2
v1: https://lore.kernel.org/netdev/20250627200551.348096-1-edumazet@google.com/
====================
Link: https://patch.msgid.link/20250630093540.3052835-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/unix/sysctl_net_unix.c')
0 files changed, 0 insertions, 0 deletions