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| author | Eric Dumazet <edumazet@google.com> | 2016-04-01 18:52:12 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-04-05 05:11:19 +0300 |
| commit | a4298e4522d687a79af8f8fbb7eca68399ab2d81 (patch) | |
| tree | d7a2c3d16b4659a7121b993f4ba690f20adc99fd /include/net/sock.h | |
| parent | 43e2dfb23eb8f3698718ec1e3936c76912de1c30 (diff) | |
| download | linux-a4298e4522d687a79af8f8fbb7eca68399ab2d81.tar.xz | |
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>
Diffstat (limited to 'include/net/sock.h')
| -rw-r--r-- | include/net/sock.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index e91b87f54f99..9e77353a92ae 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -438,6 +438,7 @@ struct sock { struct sk_buff *skb); void (*sk_destruct)(struct sock *sk); struct sock_reuseport __rcu *sk_reuseport_cb; + struct rcu_head sk_rcu; }; #define __sk_user_data(sk) ((*((void __rcu **)&(sk)->sk_user_data))) @@ -720,6 +721,7 @@ enum sock_flags { */ SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */ SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */ + SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */ }; #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE)) |