net: do not abort bulk send on BQL status
authorEric Dumazet <edumazet@google.com>
Wed, 31 Oct 2018 15:39:13 +0000 (08:39 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 28 Nov 2019 17:28:54 +0000 (18:28 +0100)
commitf4e7ca091d480c10a4eaaa72b500c1eee7948c02
tree5365132ec1799e4e024465153e947a3fed539164
parentbcb7267a915d800954e2412f44224a0b458329a8
net: do not abort bulk send on BQL status

[ Upstream commit fe60faa5063822f2d555f4f326c7dd72a60929bf ]

Before calling dev_hard_start_xmit(), upper layers tried
to cook optimal skb list based on BQL budget.

Problem is that GSO packets can end up comsuming more than
the BQL budget.

Breaking the loop is not useful, since requeued packets
are ahead of any packets still in the qdisc.

It is also more expensive, since next TX completion will
push these packets later, while skbs are not in cpu caches.

It is also a behavior difference with TSO packets, that can
break the BQL limit by a large amount.

Note that drivers should use __netdev_tx_sent_queue()
in order to have optimal xmit_more support, and avoid
useless atomic operations as shown in the following patch.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net/core/dev.c