Wei Xu dee5b428c3 vhost: fix skb leak in handle_rx() ... [ Upstream commit 6e474083f3 ] Matthew found a roughly 40% tcp throughput regression with commit c67df11f(vhost_net: try batch dequing from skb array) as discussed in the following thread: https://www.mail-archive.com/netdev@vger.kernel.org/msg187936.html Eventually we figured out that it was a skb leak in handle_rx() when sending packets to the VM. This usually happens when a guest can not drain out vq as fast as vhost fills in, afterwards it sets off the traffic jam and leaks skb(s) which occurs as no headcount to send on the vq from vhost side. This can be avoided by making sure we have got enough headcount before actually consuming a skb from the batched rx array while transmitting, which is simply done by moving checking the zero headcount a bit ahead. Signed-off-by: Wei Xu <wexu@redhat.com> Reported-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2017-12-17 15:07:56 +01:00
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Kconfig	tap: tap as an independent module	2017-02-11 20:59:41 -05:00
Kconfig.vringh	vhost: split out vringh Kconfig	2016-08-02 16:54:28 +03:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
net.c	vhost: fix skb leak in handle_rx()	2017-12-17 15:07:56 +01:00
scsi.c	fix a page leak in vhost_scsi_iov_to_sgl() error recovery	2017-11-30 08:40:49 +00:00
test.c	Merge 4.8-rc5 into char-misc-next	2016-09-05 08:04:07 +02:00
test.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
vhost.c	lib/interval_tree: fast overlap detection	2017-09-08 18:26:49 -07:00
vhost.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
vringh.c	vringh: kill off ACCESS_ONCE()	2016-12-16 00:13:36 +02:00
vsock.c	mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic	2017-07-12 16:26:03 -07:00