On Fri, Jul 07, 2017 at 11:05:22AM +0100, Ferruh Yigit wrote:

On 7/7/2017 1:09 AM, Gaetan Rivet wrote:

quoted

This PMD intercepts and manages Ethernet device removal events issued by
slave PMDs and re-initializes them transparently when brought back so that
existing applications do not need to be modified to benefit from true
hot-plugging support.

The stacked PMD approach shares many similarities with the bonding PMD but
with a different purpose. While bonding provides the ability to group
several links into a single logical device for enhanced throughput and
supports fail-over at link level, this one manages the sudden disappearance
of the underlying device; it guarantees applications face a valid device in
working order at all times.

Each fail-safe instance is configured to run atop one or several
devices, with one defined as the preferred device. Hot-plug events are
handled on all of them, and Tx is always directed to the preferred device
if present or to the next available failover device (Rx is always performed
on all devices for simplicity).

Moreover, the configured slaves (preferred or failover) do not need to be
present at initialization time and may appear later.

Slaves configuration is continuously synchronized with that of the virtual
device, which exposes their common set of capabilities to the application.
Failure to apply the current configuration state to a slave for any reason
simply reschedules its initialization.

This patchset depends on:

eal: complete attach / detach support
http://dpdk.org/ml/archives/dev/2017-May/066366.html
http://dpdk.org/dev/patchwork/patch/24522/

ethdev: add flow API rule copy function
http://dpdk.org/ml/archives/dev/2017-May/066145.html
http://dpdk.org/dev/patchwork/patch/24406/

ethdev: add isolated mode to flow API
http://dpdk.org/ml/archives/dev/2017-April/064327.html
http://dpdk.org/dev/patchwork/patch/23741/

v1 --> v2:

  - Wrote documentation
  - Fixed commit logs, signed-off-by
  - Added LSC event support
  - A few minor fixes

v2 --> v3:

  - Numerous bug fixes.
  - Complete sub-EAL rework to follow new bus API.
  - burst protection on sub removal.
  - more flexible sub definition.
  - flow isolated mode support.

v3 --> v4:

  - Split back commits
       net/failsafe: add fast burst functions
       net/failsafe: support device removal
    That were squashed by error during a rebase
  - Fix segfault on port plugin
  - Fix isolate mode support for MLX4 ports plugin

v4 --> v5:

  - Follow new plug / unplug API.

v5 --> v6:

  - Follow new hotplug API.
  - Improve usability of hotplug API.
  - Fix rte_dev hotplug API implementation.
  - Introduce rte_eal_devargs_rmv API as EXPERIMENTAL.
  - Use it to clean up resources on hotplug_remove.
  - Fix hotplug implementation and support un pci bus.
    The scan was not idempotent, nor clean.
    Neither were the device fields.
  - Implement plug operation for vdev bus.
    This is needed for hotplug support and to make the EAL
    independent from vdev-specific API.
  - Remove useless parameters from plug / unplug API.

This patchset is fairly big and complex. The hotplug API has been rushed and
has never been tested outside of the special case of vdev bus.

These evolutions are proposed alongside this PMD as only this PMD allows to test
this API at the moment, and without those evolutions this PMD cannot be used.

Gaetan Rivet (22):
  eal: return device handle upon plugin
  eal: fix hotplug add
  devargs: introduce removal function
  eal: release devargs on device removal
  pci: use given name as generic name
  pci: fix generic driver pointer on probe error
  pci: fix hotplug operations
  vdev: add dev to vdev macro
  vdev: implement plug operation
  bus: remove useless plug parameter
  ethdev: save VLAN filter setting
  ethdev: add deferred intermediate device state
  ethdev: count devices consistently
  net/failsafe: add fail-safe PMD
  net/failsafe: add plug-in support
  net/failsafe: add flexible device definition
  net/failsafe: support flow API
  net/failsafe: support offload capabilities
  net/failsafe: add fast burst functions
  net/failsafe: support device removal
  net/failsafe: support link status change event
  net/failsafe: support flow API isolation mode

Hi Gaetan,

The failsafe PMD postponed to RC2, to mainly let eal level dependencies
be resolved first, and I believe it is OK to get a PMD in RC2 because
its scope is limited.

But in this new version of the patchset, there are many patches touches
to eal and ethdev level. I don't think it is good idea to get these
changes in RC2 and with next-net tree.

I believe these should be resolved in main repo, in RC1. And failsafe as
a PMD, can go in RC2 via next-net.

What do you think separating eal and ethdev bits of the patchset and
target RC1?

Sure, I'm all for it. The only reason I presented them both at once was
because the changes that would then be included in RC1 will be hard to
test without the fail-safe PMD.

But it makes sense to stabilize the lib changes before integrating the
fail-safe.

Thanks,
ferruh

-- 
Gaëtan Rivet
6WIND