similar to: [PATCH v2] virtio_net: fix support for small rings

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

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"

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. So this patch fixes this by reserving enough tailroom and using fixed size of rx buffer. Signed-off-by: Jason Wang <jasowang at

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. So this patch fixes this by reserving enough tailroom and using fixed size of rx buffer. Signed-off-by: Jason Wang <jasowang at

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 Fri, Mar 02, 2018 at 05:29:14PM +0800, Jason Wang wrote: > XDP_REDIRECT support for mergeable buffer was removed since commit > 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() > case"). This is because we don't reserve enough tailroom for struct > skb_shared_info which breaks XDP assumption. So this patch fixes this > by reserving enough

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. So this patch fixes this by reserving enough tailroom and using fixed size of rx buffer. Signed-off-by: Jason Wang <jasowang at

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. So this patch fixes this by reserving enough tailroom and using fixed size of rx buffer. Signed-off-by: Jason Wang <jasowang at

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. Other complaints are, the complex linearize logic and EWMA estimation may increase the possibility of linearizing. Signed-off-by:

On Thu, Mar 01, 2018 at 11:19:04AM +0800, Jason Wang wrote: > XDP_REDIRECT support for mergeable buffer was removed since commit > 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() > case"). This is because we don't reserve enough tailroom for struct > skb_shared_info which breaks XDP assumption. Other complaints are, the > complex linearize logic

Hi: This series tries to re-enable XDP_REDIRECT for mergeable buffer which was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). Main concerns are: - not enough tailroom was reserved which breaks cpumap - complex logic like EWMA and linearizing during XDP processing Fix those by: - reserve enough tailroom during refill - disable EWMA

Hi: This series tries to re-enable XDP_REDIRECT for mergeable buffer which was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). Main concerns are: - not enough tailroom was reserved which breaks cpumap - complex logic like EWMA and linearizing during XDP processing Fix those by: - reserve enough tailroom during refill - disable EWMA

Sorry, forgot to Cc Michael and the virt list - patch reproduced below in full. johannes >From 22500fbcf722748fe3471b2e4c6156db47aade15 Mon Sep 17 00:00:00 2001 From: Johannes Berg <johannes.berg at intel.com> Date: Wed, 19 Aug 2015 09:25:18 +0200 Subject: [PATCH] virtio_net: use DECLARE_EWMA Instead of using the out-of-line EWMA calculation, use DECLARE_EWMA() to create static

Sorry, forgot to Cc Michael and the virt list - patch reproduced below in full. johannes >From 22500fbcf722748fe3471b2e4c6156db47aade15 Mon Sep 17 00:00:00 2001 From: Johannes Berg <johannes.berg at intel.com> Date: Wed, 19 Aug 2015 09:25:18 +0200 Subject: [PATCH] virtio_net: use DECLARE_EWMA Instead of using the out-of-line EWMA calculation, use DECLARE_EWMA() to create static

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.

Add initial support for per-rx queue sysfs attributes to virtio-net. If mergeable packet buffers are enabled, adds a read-only mergeable packet buffer size sysfs attribute for each RX queue. Signed-off-by: Michael Dalton <mwdalton at google.com> --- drivers/net/virtio_net.c | 66 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 62 insertions(+), 4 deletions(-) diff --git