[v6] virtio-net: Link queues to NAPIs

[PATCH net-next v6 0/4] virtio-net: Link queues to NAPIs

Posted by Joe Damato 9 months, 2 weeks ago

Greetings:

Welcome to v6. Only patch updated is patch 3. See changelog below.

Jakub recently commented [1] that I should not hold this series on
virtio-net linking queues to NAPIs behind other important work that is
on-going and suggested I re-spin, so here we are :)

As per the discussion on the v3 [2], now both RX and TX NAPIs use the
API to link queues to NAPIs. Since TX-only NAPIs don't have a NAPI ID,
commit 6597e8d35851 ("netdev-genl: Elide napi_id when not present") now
correctly elides the TX-only NAPIs (instead of printing zero) when the
queues and NAPIs are linked.

As per the discussion on the v4 [3], patch 3 has been refactored to hold
RTNL only in the specific locations which need it as Jason requested.

As per the discussion on the v5 [4], patch 3 now leaves refill_work
as-is and does not use the API to unlink and relink queues and NAPIs. A
comment has been left as suggested by Jakub [5] for future work.

See the commit message of patch 3 for an example of how to get the NAPI
to queue mapping information.

See the commit message of patch 4 for an example of how NAPI IDs are
persistent despite queue count changes.

Thanks,
Joe

[1]: https://lore.kernel.org/netdev/20250221142650.3c74dcac@kernel.org/
[2]: https://lore.kernel.org/netdev/20250127142400.24eca319@kernel.org/
[3]: https://lore.kernel.org/netdev/CACGkMEv=ejJnOWDnAu7eULLvrqXjkMkTL4cbi-uCTUhCpKN_GA@mail.gmail.com/
[4]: https://lore.kernel.org/lkml/Z8X15hxz8t-vXpPU@LQ3V64L9R2/
[5]: https://lore.kernel.org/lkml/20250303160355.5f8d82d8@kernel.org/

v6:
- Patch 3 has been updated to avoid using the queue linking API from
refill_work and a comment has been added to instruct future
work on the code.

v5: https://lore.kernel.org/lkml/20250227185017.206785-1-jdamato@fastly.com/
- Patch 1 added Acked-by's from Michael and Jason. Added Tested-by
from Lei. No functional changes.
- Patch 2 added Acked-by's from Michael and Jason. Added Tested-by
from Lei. No functional changes.
- Patch 3:
- Refactored as Jason requested, eliminating the
virtnet_queue_set_napi helper entirely, and explicitly holding
RTNL in the 3 locations where needed (refill_work, freeze, and
restore).
- Commit message updated to outline the known paths at the time the
commit was written.
- Patch 4 added Acked-by from Michael. Added Tested-by from Lei. No
functional changes.

v4: https://lore.kernel.org/lkml/20250225020455.212895-1-jdamato@fastly.com/
- Dropped Jakub's patch (previously patch 1).
- Significant refactor from v3 affecting patches 1-3.
- Patch 4 added tags from Jason and Gerhard.

rfcv3: https://lore.kernel.org/netdev/20250121191047.269844-1-jdamato@fastly.com/
- patch 3:
- Removed the xdp checks completely, as Gerhard Engleder pointed
out, they are likely not necessary.

- patch 4:
- Added Xuan Zhuo's Reviewed-by.

v2: https://lore.kernel.org/netdev/20250116055302.14308-1-jdamato@fastly.com/
- patch 1:
- New in the v2 from Jakub.

- patch 2:
- Previously patch 1, unchanged from v1.
- Added Gerhard Engleder's Reviewed-by.
- Added Lei Yang's Tested-by.

- patch 3:
- Introduced virtnet_napi_disable to eliminate duplicated code
in virtnet_xdp_set, virtnet_rx_pause, virtnet_disable_queue_pair,
refill_work as suggested by Jason Wang.
- As a result of the above refactor, dropped Reviewed-by and
Tested-by from patch 3.

- patch 4:
- New in v2. Adds persistent NAPI configuration. See commit message
for more details.

v1: https://lore.kernel.org/netdev/20250110202605.429475-1-jdamato@fastly.com/

Joe Damato (4):
virtio-net: Refactor napi_enable paths
virtio-net: Refactor napi_disable paths
virtio-net: Map NAPIs to queues
virtio_net: Use persistent NAPI config

drivers/net/virtio_net.c | 101 ++++++++++++++++++++++++++++-----------
1 file changed, 74 insertions(+), 27 deletions(-)

base-commit: 8e0e8bef484160ac01ea7bcc3122cc1f0405c982
--
2.45.2

Re: [PATCH net-next v6 0/4] virtio-net: Link queues to NAPIs

Posted by Xuan Zhuo 9 months, 2 weeks ago

Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

On Fri,  7 Mar 2025 01:12:08 +0000, Joe Damato <jdamato@fastly.com> wrote:
> Greetings:
>
> Welcome to v6. Only patch updated is patch 3. See changelog below.
>
> Jakub recently commented [1] that I should not hold this series on
> virtio-net linking queues to NAPIs behind other important work that is
> on-going and suggested I re-spin, so here we are :)
>
> As per the discussion on the v3 [2], now both RX and TX NAPIs use the
> API to link queues to NAPIs. Since TX-only NAPIs don't have a NAPI ID,
> commit 6597e8d35851 ("netdev-genl: Elide napi_id when not present") now
> correctly elides the TX-only NAPIs (instead of printing zero) when the
> queues and NAPIs are linked.
>
> As per the discussion on the v4 [3], patch 3 has been refactored to hold
> RTNL only in the specific locations which need it as Jason requested.
>
> As per the discussion on the v5 [4], patch 3 now leaves refill_work
> as-is and does not use the API to unlink and relink queues and NAPIs. A
> comment has been left as suggested by Jakub [5] for future work.
>
> See the commit message of patch 3 for an example of how to get the NAPI
> to queue mapping information.
>
> See the commit message of patch 4 for an example of how NAPI IDs are
> persistent despite queue count changes.
>
> Thanks,
> Joe
>
> [1]: https://lore.kernel.org/netdev/20250221142650.3c74dcac@kernel.org/
> [2]: https://lore.kernel.org/netdev/20250127142400.24eca319@kernel.org/
> [3]: https://lore.kernel.org/netdev/CACGkMEv=ejJnOWDnAu7eULLvrqXjkMkTL4cbi-uCTUhCpKN_GA@mail.gmail.com/
> [4]: https://lore.kernel.org/lkml/Z8X15hxz8t-vXpPU@LQ3V64L9R2/
> [5]: https://lore.kernel.org/lkml/20250303160355.5f8d82d8@kernel.org/
>
> v6:
>   - Patch 3 has been updated to avoid using the queue linking API from
>     refill_work and a comment has been added to instruct future
>     work on the code.
>
> v5: https://lore.kernel.org/lkml/20250227185017.206785-1-jdamato@fastly.com/
>   - Patch 1 added Acked-by's from Michael and Jason. Added Tested-by
>     from Lei. No functional changes.
>   - Patch 2 added Acked-by's from Michael and Jason. Added Tested-by
>     from Lei. No functional changes.
>   - Patch 3:
>     - Refactored as Jason requested, eliminating the
>       virtnet_queue_set_napi helper entirely, and explicitly holding
>       RTNL in the 3 locations where needed (refill_work, freeze, and
>       restore).
>     - Commit message updated to outline the known paths at the time the
>       commit was written.
>   - Patch 4 added Acked-by from Michael. Added Tested-by from Lei. No
>     functional changes.
>
> v4: https://lore.kernel.org/lkml/20250225020455.212895-1-jdamato@fastly.com/
>   - Dropped Jakub's patch (previously patch 1).
>   - Significant refactor from v3 affecting patches 1-3.
>   - Patch 4 added tags from Jason and Gerhard.
>
> rfcv3: https://lore.kernel.org/netdev/20250121191047.269844-1-jdamato@fastly.com/
>   - patch 3:
>     - Removed the xdp checks completely, as Gerhard Engleder pointed
>       out, they are likely not necessary.
>
>   - patch 4:
>     - Added Xuan Zhuo's Reviewed-by.
>
> v2: https://lore.kernel.org/netdev/20250116055302.14308-1-jdamato@fastly.com/
>   - patch 1:
>     - New in the v2 from Jakub.
>
>   - patch 2:
>     - Previously patch 1, unchanged from v1.
>     - Added Gerhard Engleder's Reviewed-by.
>     - Added Lei Yang's Tested-by.
>
>   - patch 3:
>     - Introduced virtnet_napi_disable to eliminate duplicated code
>       in virtnet_xdp_set, virtnet_rx_pause, virtnet_disable_queue_pair,
>       refill_work as suggested by Jason Wang.
>     - As a result of the above refactor, dropped Reviewed-by and
>       Tested-by from patch 3.
>
>   - patch 4:
>     - New in v2. Adds persistent NAPI configuration. See commit message
>       for more details.
>
> v1: https://lore.kernel.org/netdev/20250110202605.429475-1-jdamato@fastly.com/
>
>
> Joe Damato (4):
>   virtio-net: Refactor napi_enable paths
>   virtio-net: Refactor napi_disable paths
>   virtio-net: Map NAPIs to queues
>   virtio_net: Use persistent NAPI config
>
>  drivers/net/virtio_net.c | 101 ++++++++++++++++++++++++++++-----------
>  1 file changed, 74 insertions(+), 27 deletions(-)
>
>
> base-commit: 8e0e8bef484160ac01ea7bcc3122cc1f0405c982
> --
> 2.45.2
>