linux_dsm_epyc7002/include
Michael S. Tsirkin 5d09710925 tun: only queue packets on device
Historically tun supported two modes of operation:
- in default mode, a small number of packets would get queued
  at the device, the rest would be queued in qdisc
- in one queue mode, all packets would get queued at the device

This might have made sense up to a point where we made the
queue depth for both modes the same and set it to
a huge value (500) so unless the consumer
is stuck the chance of losing packets is small.

Thus in practice both modes behave the same, but the
default mode has some problems:
- if packets are never consumed, fragments are never orphaned
  which cases a DOS for sender using zero copy transmit
- overrun errors are hard to diagnose: fifo error is incremented
  only once so you can not distinguish between
  userspace that is stuck and a transient failure,
  tcpdump on the device does not show any traffic

Userspace solves this simply by enabling IFF_ONE_QUEUE
but there seems to be little point in not doing the
right thing for everyone, by default.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-12-03 15:07:36 -05:00
..
acpi Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2012-10-08 07:14:06 +09:00
asm-generic UAPI: Remove empty non-UAPI Kbuild files 2012-10-17 12:31:15 +01:00
clocksource arm64: Generic timers support 2012-09-17 13:42:20 +01:00
crypto Merge branch 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux 2012-10-14 13:39:34 -07:00
drm drm/radeon: add new SI pci id 2012-11-21 18:37:38 -05:00
keys KEYS: Asymmetric key pluggable data parsers 2012-10-08 13:50:13 +10:30
linux Merge git://git.infradead.org/users/dwmw2/atm 2012-12-01 20:45:24 -05:00
math-emu
media [media] adv7604: Replace prim_mode by mode 2012-11-21 17:43:49 -02:00
memory
misc
net sctp: Add support to per-association statistics via a new SCTP_GET_ASSOC_STATS call 2012-12-03 13:32:15 -05:00
pcmcia
ras
rdma infiniband: pass rdma_cm module to netlink_dump_start 2012-10-07 00:30:56 -04:00
rxrpc
scsi [SCSI] sd: Implement support for WRITE SAME 2012-11-13 22:45:42 -08:00
sound ALSA: Add a reference counter to card instance 2012-10-30 11:07:10 +01:00
target target: Add target_submit_cmd_map_sgls for SGL fabric memory passthrough 2012-10-02 14:16:08 -07:00
trace Revert "mm: remove __GFP_NO_KSWAPD" 2012-11-26 17:41:24 -08:00
uapi tun: only queue packets on device 2012-12-03 15:07:36 -05:00
video fbdev updates for 3.7 2012-10-12 10:21:02 +09:00
xen Bug-fixes: 2012-11-10 06:56:21 +01:00
Kbuild UAPI: Remove empty non-UAPI Kbuild files 2012-10-17 12:31:15 +01:00