Re: [dpdk-dev] [PATCH 6/9] net/ifc: add devarg for LM mode

[Alejandro Lucero <alejandro.lucero@netronome.com>]

On Wed, Nov 28, 2018 at 9:56 AM Xiao Wang <xiao.w.wang@intel.com> wrote:

> This patch series enables a new method for live migration, i.e. software
> assisted live migration. This patch provides a device argument for user
> to choose the methold.
>
> When "swlm=1", driver/device will do live migration with a relay thread
> dealing with dirty page logging. Without this parameter, device will do
> dirty page logging and there's no relay thread consuming CPU resource.
>
>
I'm a bit confused with this mode. If it is a relay thread doing the dirty
page logging, does it mean that the datapath is through the relay thread
and not between the VM and the vdpa device?


> Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
> ---
>  drivers/net/ifc/ifcvf_vdpa.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/drivers/net/ifc/ifcvf_vdpa.c b/drivers/net/ifc/ifcvf_vdpa.c
> index c0e50354a..e9cc8d7bc 100644
> --- a/drivers/net/ifc/ifcvf_vdpa.c
> +++ b/drivers/net/ifc/ifcvf_vdpa.c
> @@ -8,6 +8,7 @@
>  #include <sys/ioctl.h>
>  #include <sys/epoll.h>
>  #include <linux/virtio_net.h>
> +#include <stdbool.h>
>
>  #include <rte_malloc.h>
>  #include <rte_memory.h>
> @@ -31,9 +32,11 @@
>  #endif
>
>  #define IFCVF_VDPA_MODE                "vdpa"
> +#define IFCVF_SW_FALLBACK_LM   "swlm"
>
>  static const char * const ifcvf_valid_arguments[] = {
>         IFCVF_VDPA_MODE,
> +       IFCVF_SW_FALLBACK_LM,
>         NULL
>  };
>
> @@ -56,6 +59,7 @@ struct ifcvf_internal {
>         rte_atomic32_t dev_attached;
>         rte_atomic32_t running;
>         rte_spinlock_t lock;
> +       bool sw_lm;
>  };
>
>  struct internal_list {
> @@ -767,6 +771,7 @@ ifcvf_pci_probe(struct rte_pci_driver *pci_drv
> __rte_unused,
>         struct ifcvf_internal *internal = NULL;
>         struct internal_list *list = NULL;
>         int vdpa_mode = 0;
> +       int sw_fallback_lm = 0;
>         struct rte_kvargs *kvlist = NULL;
>         int ret = 0;
>
> @@ -826,6 +831,16 @@ ifcvf_pci_probe(struct rte_pci_driver *pci_drv
> __rte_unused,
>         internal->dev_addr.type = PCI_ADDR;
>         list->internal = internal;
>
> +       if (rte_kvargs_count(kvlist, IFCVF_SW_FALLBACK_LM)) {
> +               ret = rte_kvargs_process(kvlist, IFCVF_SW_FALLBACK_LM,
> +                               &open_int, &sw_fallback_lm);
> +               if (ret < 0)
> +                       goto error;
> +               internal->sw_lm = sw_fallback_lm ? true : false;
> +       } else {
> +               internal->sw_lm = false;
> +       }
> +
>         internal->did = rte_vdpa_register_device(&internal->dev_addr,
>                                 &ifcvf_ops);
>         if (internal->did < 0) {
> --
> 2.15.1
>
>