similar to: [PATCH] virtio_net: lower limit on buffer size

commit d85b758f72b0 ("virtio_net: fix support for small rings") was supposed to increase the buffer size for small rings but had an unintentional side effect of decreasing it for large rings. This seems to break some setups - it's not yet clear why, but increasing buffer size back to what it was before helps. Fixes: d85b758f72b0 ("virtio_net: fix support for small rings")

commit d85b758f72b0 ("virtio_net: fix support for small rings") was supposed to increase the buffer size for small rings but had an unintentional side effect of decreasing it for large rings. This seems to break some setups - it's not yet clear why, but increasing buffer size back to what it was before helps. Fixes: d85b758f72b0 ("virtio_net: fix support for small rings")

On Tue, May 30, 2017 at 07:26:37PM +0300, Michael S. Tsirkin wrote: > On Fri, May 26, 2017 at 03:31:33PM -0400, bfields at fieldses.org wrote: > > Looks like the culprit is very likely d85b758f72b0 "virtio_net: fix > > support for small rings". > > > > After that patch, my NFS server VM stops responding to packets after a > > few minutes of testing.

On Tue, May 30, 2017 at 07:26:37PM +0300, Michael S. Tsirkin wrote: > On Fri, May 26, 2017 at 03:31:33PM -0400, bfields at fieldses.org wrote: > > Looks like the culprit is very likely d85b758f72b0 "virtio_net: fix > > support for small rings". > > > > After that patch, my NFS server VM stops responding to packets after a > > few minutes of testing.

Looks like the culprit is very likely d85b758f72b0 "virtio_net: fix support for small rings". After that patch, my NFS server VM stops responding to packets after a few minutes of testing. Before that patch, my server keeps working. --b.

On Tue, May 30, 2017 at 07:26:37PM +0300, Michael S. Tsirkin wrote: > On Fri, May 26, 2017 at 03:31:33PM -0400, bfields at fieldses.org wrote: > > Looks like the culprit is very likely d85b758f72b0 "virtio_net: fix > > support for small rings". > > > > After that patch, my NFS server VM stops responding to packets after a > > few minutes of testing.

On Tue, May 30, 2017 at 07:26:37PM +0300, Michael S. Tsirkin wrote: > On Fri, May 26, 2017 at 03:31:33PM -0400, bfields at fieldses.org wrote: > > Looks like the culprit is very likely d85b758f72b0 "virtio_net: fix > > support for small rings". > > > > After that patch, my NFS server VM stops responding to packets after a > > few minutes of testing.

Probably should have cc'd virtualization at lists.linux-foundation.org too. On Fri, May 26, 2017 at 11:08:39AM -0400, bfields at fieldses.org wrote: > On Tue, May 23, 2017 at 08:23:34AM -0400, bfields at fieldses.org wrote: > > Unfortunately I can't get anything through testing. It's not your > > patches, it's something in -rc1. My server VM stops responding to

Probably should have cc'd virtualization at lists.linux-foundation.org too. On Fri, May 26, 2017 at 11:08:39AM -0400, bfields at fieldses.org wrote: > On Tue, May 23, 2017 at 08:23:34AM -0400, bfields at fieldses.org wrote: > > Unfortunately I can't get anything through testing. It's not your > > patches, it's something in -rc1. My server VM stops responding to

When ring size is small (<32 entries) making buffers smaller means a full ring might not be able to hold enough buffers to fit a single large packet. Make sure a ring full of buffers is large enough to allow at least one packet of max size. Fixes: 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag allocators") Signed-off-by: Michael S. Tsirkin <mst at

When ring size is small (<32 entries) making buffers smaller means a full ring might not be able to hold enough buffers to fit a single large packet. Make sure a ring full of buffers is large enough to allow at least one packet of max size. Fixes: 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag allocators") Signed-off-by: Michael S. Tsirkin <mst at

When ring size is small (<32 entries) making buffers smaller means a full ring might not be able to hold enough buffers to fit a single large packet. Make sure a ring full of buffers is large enough to allow at least one packet of max size. Fixes: 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag allocators") Signed-off-by: Michael S. Tsirkin <mst at

When ring size is small (<32 entries) making buffers smaller means a full ring might not be able to hold enough buffers to fit a single large packet. Make sure a ring full of buffers is large enough to allow at least one packet of max size. Fixes: 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag allocators") Signed-off-by: Michael S. Tsirkin <mst at

On Fri, Jun 02, 2017 at 12:34:57PM +0300, Sergei Shtylyov wrote: > Hello! > > On 6/2/2017 2:56 AM, Michael S. Tsirkin wrote: > > >commit d85b758f72b0 "virtio_net: fix support for small rings" > > Commit d85b758f72b0 ("virtio_net: fix support for small rings") > > >was supposed to increase the buffer size for small rings > >but had

On Fri, Jun 02, 2017 at 12:34:57PM +0300, Sergei Shtylyov wrote: > Hello! > > On 6/2/2017 2:56 AM, Michael S. Tsirkin wrote: > > >commit d85b758f72b0 "virtio_net: fix support for small rings" > > Commit d85b758f72b0 ("virtio_net: fix support for small rings") > > >was supposed to increase the buffer size for small rings > >but had

On Fri, May 26, 2017 at 03:31:33PM -0400, bfields at fieldses.org wrote: > Looks like the culprit is very likely d85b758f72b0 "virtio_net: fix > support for small rings". > > After that patch, my NFS server VM stops responding to packets after a > few minutes of testing. Before that patch, my server keeps working. > > --b. Others complained about that too.

On Wed, 18 Apr 2018, David Miller wrote: > From: Mikulas Patocka <mpatocka at redhat.com> > Date: Wed, 18 Apr 2018 12:44:25 -0400 (EDT) > > > The structure net_device is followed by arbitrary driver-specific data > > (accessible with the function netdev_priv). And for virtio-net, these > > driver-specific data must be in DMA memory. > > And we are saying

Hi I see severe network performance degradation with the kernels 4.12-rc1 and 4.12-rc2 in the network virtio driver. Download rate drops down to about 100kB/s. I bisected it and it is caused by patch d85b758f72b05a774045545f24d70980e3e9aac4 ("virtio_net: fix support for small rings"). When I revert this patch, the problem goes away. The host is Debian Jessie with kernel 4.4.62,

Hi I see severe network performance degradation with the kernels 4.12-rc1 and 4.12-rc2 in the network virtio driver. Download rate drops down to about 100kB/s. I bisected it and it is caused by patch d85b758f72b05a774045545f24d70980e3e9aac4 ("virtio_net: fix support for small rings"). When I revert this patch, the problem goes away. The host is Debian Jessie with kernel 4.4.62,

Hello! On 6/2/2017 2:56 AM, Michael S. Tsirkin wrote: > commit d85b758f72b0 "virtio_net: fix support for small rings" Commit d85b758f72b0 ("virtio_net: fix support for small rings") > was supposed to increase the buffer size for small rings > but had an unintentional side effect of decreasing > it for large rings. This seems to break some setups - >