linux-stable.git/drivers/vhost/net.c, branch v3.13

vhost_net: correctly limit the max pending buffers

2013-09-04T02:46:58+00:00

As Michael point out, We used to limit the max pending DMAs to get better cache
utilization. But it was not done correctly since it was one done when there's no
new buffers submitted from guest. Guest can easily exceeds the limitation by
keeping sending packets.

So this patch moves the check into main loop. Tests shows about 5%-10%
improvement on per cpu throughput for guest tx.

Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

vhost_net: poll vhost queue after marking DMA is done

2013-09-04T02:46:57+00:00

We used to poll vhost queue before making DMA is done, this is racy if vhost
thread were waked up before marking DMA is done which can result the signal to
be missed. Fix this by always polling the vhost thread before DMA is done.

Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

vhost_net: determine whether or not to use zerocopy at one time

2013-09-04T02:46:57+00:00

Currently, even if the packet length is smaller than VHOST_GOODCOPY_LEN, if
upend_idx != done_idx we still set zcopy_used to true and rollback this choice
later. This could be avoided by determining zerocopy once by checking all
conditions at one time before.

Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used()

2013-09-04T02:46:57+00:00

We tend to batch the used adding and signaling in vhost_zerocopy_callback()
which may result more than 100 used buffers to be updated in
vhost_zerocopy_signal_used() in some cases. So switch to use
vhost_add_used_and_signal_n() to avoid multiple calls to
vhost_add_used_and_signal(). Which means much less times of used index
updating and memory barriers.

2% performance improvement were seen on netperf TCP_RR test.

Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

vhost_net: make vhost_zerocopy_signal_used() return void

2013-09-04T02:46:57+00:00

None of its caller use its return value, so let it return void.

Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

vhost: Remove custom vhost rcu usage

2013-07-11T12:38:40+00:00

Now, vq->private_data is always accessed under vq mutex. No need to play
the vhost rcu trick.

Signed-off-by: Asias He 
Signed-off-by: Michael S. Tsirkin

vhost-net: Always access vq->private_data under vq mutex

2013-07-11T12:36:45+00:00

Signed-off-by: Asias He 
Signed-off-by: Michael S. Tsirkin

vhost: Make local function static

2013-07-07T14:34:07+00:00

$ make C=1 M=drivers/vhost

drivers/vhost/net.c:168:5: warning: symbol 'vhost_net_set_ubuf_info' was not declared. Should it be static?
drivers/vhost/net.c:194:6: warning: symbol 'vhost_net_vq_reset' was not declared. Should it be static?
drivers/vhost/scsi.c:219:6: warning: symbol 'tcm_vhost_done_inflight' was not declared. Should it be static?

Signed-off-by: Asias He 
Signed-off-by: Michael S. Tsirkin

vhost-net: fix use-after-free in vhost_net_flush

2013-07-07T11:06:22+00:00

vhost_net_ubuf_put_and_wait has a confusing name:
it will actually also free it's argument.
Thus since commit 1280c27f8e29acf4af2da914e80ec27c3dbd5c01
    "vhost-net: flush outstanding DMAs on memory change"
vhost_net_flush tries to use the argument after passing it
to vhost_net_ubuf_put_and_wait, this results
in use after free.
To fix, don't free the argument in vhost_net_ubuf_put_and_wait,
add an new API for callers that want to free ubufs.

Acked-by: Asias He 
Acked-by: Jason Wang 
Signed-off-by: Michael S. Tsirkin

vhost: fix ubuf_info cleanup

2013-06-11T09:46:21+00:00

vhost_net_clear_ubuf_info didn't clear ubuf_info
after kfree, this could trigger double free.
Fix this and simplify this code to make it more robust: make sure
ubuf info is always freed through vhost_net_clear_ubuf_info.

Reported-by: Tommi Rantala 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller