Commits
Eric Dumazet committed a4298e4522d
net: add SOCK_RCU_FREE socket flag We want a generic way to insert an RCU grace period before socket freeing for cases where RCU_SLAB_DESTROY_BY_RCU is adding too much overhead. SLAB_DESTROY_BY_RCU strict rules force us to take a reference on the socket sk_refcnt, and it is a performance problem for UDP encapsulation, or TCP synflood behavior, as many CPUs might attempt the atomic operations on a shared sk_refcnt UDP sockets and TCP listeners can set SOCK_RCU_FREE so that their lookup can use traditional RCU rules, without refcount changes. They can set the flag only once hashed and visible by other cpus. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <tom@herbertland.com> Tested-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>