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authorPaolo Abeni <pabeni@redhat.com>2017-05-16 12:20:14 +0300
committerDavid S. Miller <davem@davemloft.net>2017-05-16 22:41:29 +0300
commit2276f58ac5890e58d2b6a48b95493faff7347e3a (patch)
treec77ce6fd0b942dfddb145e1ad6dbb2fb1942d849 /include/linux/udp.h
parent65101aeca52241a05e66f23c96eb896c9412718d (diff)
downloadlinux-2276f58ac5890e58d2b6a48b95493faff7347e3a.tar.xz
udp: use a separate rx queue for packet reception
under udp flood the sk_receive_queue spinlock is heavily contended. This patch try to reduce the contention on such lock adding a second receive queue to the udp sockets; recvmsg() looks first in such queue and, only if empty, tries to fetch the data from sk_receive_queue. The latter is spliced into the newly added queue every time the receive path has to acquire the sk_receive_queue lock. The accounting of forward allocated memory is still protected with the sk_receive_queue lock, so udp_rmem_release() needs to acquire both locks when the forward deficit is flushed. On specific scenarios we can end up acquiring and releasing the sk_receive_queue lock multiple times; that will be covered by the next patch Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/udp.h')
-rw-r--r--include/linux/udp.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 6cb4061a720d..eaea63bc79bb 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -80,6 +80,9 @@ struct udp_sock {
struct sk_buff *skb,
int nhoff);
+ /* udp_recvmsg try to use this before splicing sk_receive_queue */
+ struct sk_buff_head reader_queue ____cacheline_aligned_in_smp;
+
/* This field is dirtied by udp_recvmsg() */
int forward_deficit;
};