Re: [net-next rfc V3 0/9] Multiqueue API for macvtap

From: Michael S. Tsirkin
Date: Wed Jun 05 2013 - 06:36:01 EST


On Wed, Jun 05, 2013 at 02:36:23PM +0800, Jason Wang wrote:
> Hi all:
>
> This series implements a v3 of fully tuntap compatiable API which could be used
> by userspace to manage multiple macvtap queues. The main parts is to add
> TUNSETQUEUE ioctl support for macvtap.
>
> Patch 1 - 5 was some tuntap compatibility and misc cleanups.
> Patch 6 removes the linear search in macvtap by reshuffling the macvtaps array
> each time a queue is removed. After this, we could store both enabled and
> disabled queues in the same array without introducing extra data structure.
> Patch 7 let TUNSETIFF can create multiqueue device, nothing but some check
> were added.
> Patch 8 implement TUNSETQUEUE ioctl
> Patch 9 reports IFF_MULTI_QUEUE to userspace to notify the userspace that the
> multiqueue API is completed.
>
> Flow caches implememtation were missed in this version, since I am doing
> rework on the tuntap flow caches. Have some some stress test with both netperf
> and pktgen.
>
> Please review, thanks.

FYI by netdev rules RFC means "don't apply yet".

> Changes from V2:
> - Don't place disabled taps in the array and use a linked like to track all taps
> - Remove unnecessary best-effort barriers
> - Add ACCESS_ONCE() for vlan->numvtaps to prevent compiler generate unexpected
> codes
> - Add a comment to explain that numvtaps is just a hint in macvtap_get_queue()
> - blank line fixes
>
> Changes from V1:
> - Drop the patch of "return -EBADFD when TUNGETIFF fails" to preserve backward
> compatibility
> - Add a small patch of optimizing macvtap_do_read() (see patch 1/8)
> - Use different functions to do tap enabling and creating
> - Use different functions to do tap disabling and closing
> - Remove the emtpy line in patch 6/8
> - Add a line in patch 3/8
> - Add a comment to explain the checking when doing TUNSETIFF with
> IFF_MULTI_QUEUE
> - Add comments to explian the second swapping when moving taps between disabled
> areas and enabled areas.
> - Fix the commit log of patch 7/8 ( v1 says the linked list were used which is
> wrong )
> - Other minor bug fixes
>
> Jason Wang (9):
> macvtap: fix a possible race between queue selection and changing
> queues
> macvtap: do not add self to waitqueue if doing a nonblock read
> macvlan: switch to use IS_ENABLED()
> macvtap: introduce macvtap_get_vlan()
> macvlan: change the max number of queues to 16
> macvtap: eliminate linear search
> macvtap: allow TUNSETIFF to create multiqueue device
> macvtap: add TUNSETQUEUE ioctl
> macvtap: enable multiqueue flag
>
> drivers/net/macvtap.c | 261 ++++++++++++++++++++++++++++++++------------
> include/linux/if_macvlan.h | 8 +-
> 2 files changed, 197 insertions(+), 72 deletions(-)
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