From: Eric Dumazet <edumazet@google.com> stable inclusion from stable-v4.19.316 commit 4f3ae7d846b4565c0b80d65ed607c3277bc984d4 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAMPH5 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 581073f626e387d3e7eed55c48c8495584ead7ba ] trafgen performance considerably sank on hosts with many cores after the blamed commit. packet_read_pending() is very expensive, and calling it in af_packet fast path defeats Daniel intent in commit b013840810c2 ("packet: use percpu mmap tx frame pending refcount") tpacket_destruct_skb() makes room for one packet, we can immediately wakeup a producer, no need to completely drain the tx ring. Fixes: 89ed5b519004 ("af_packet: Block execution of tasks waiting for transmit to complete in AF_PACKET") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/r/20240515163358.4105915-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/packet/af_packet.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index c64bcba21e47..e26ee0486ded 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2437,8 +2437,7 @@ static void tpacket_destruct_skb(struct sk_buff *skb) ts = __packet_set_timestamp(po, ph, skb); __packet_set_status(po, ph, TP_STATUS_AVAILABLE | ts); - if (!packet_read_pending(&po->tx_ring)) - complete(&po->skb_completion); + complete(&po->skb_completion); } sock_wfree(skb); -- 2.25.1