> -----Original Message-----
> From: Chi Song <Song.Chi@xxxxxxxxxxxxx>
> Sent: Monday, July 20, 2020 3:17 AM
> To: KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang
> <haiyangz@xxxxxxxxxxxxx>; Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>;
> Wei Liu <wei.liu@xxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Jakub
> Kicinski <kuba@xxxxxxxxxx>
> Cc: linux-hyperv@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH v3 net-next] net: hyperv: Add attributes to show TX indirection
> table
>
> An imbalanced TX indirection table causes netvsc to have low
> performance. This table is created and managed during runtime. To help
> better diagnose performance issues caused by imbalanced tables, add
> device attributes to show the content of TX indirection tables.
>
> Signed-off-by: Chi Song <chisong@xxxxxxxxxxxxx>
> ---
> v2: remove RX as it's in ethtool already, show single value in each file,
> and update description.
> v3: fix broken format by alpine.
>
> Thank you for comments. Let me know, if I miss something.
>
> ---
> drivers/net/hyperv/netvsc_drv.c | 53 +++++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 6267f706e8ee..222c2fad9300 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -2370,6 +2370,55 @@ static int netvsc_unregister_vf(struct net_device
> *vf_netdev)
> return NOTIFY_OK;
> }
>
> +static struct device_attribute
> dev_attr_netvsc_dev_attrs[VRSS_SEND_TAB_SIZE];
> +static struct attribute *netvsc_dev_attrs[VRSS_SEND_TAB_SIZE + 1];
> +
> +const struct attribute_group netvsc_dev_group = {
> + .name = NULL,
> + .attrs = netvsc_dev_attrs,
> +};
> +
> +static ssize_t tx_indirection_table_show(struct device *dev,
> + struct device_attribute *dev_attr,
> + char *buf)
> +{
> + struct net_device *ndev = to_net_dev(dev);
> + struct net_device_context *ndc = netdev_priv(ndev);
> + ssize_t offset = 0;
> + int index = dev_attr - dev_attr_netvsc_dev_attrs;
> +
> + offset = sprintf(buf, "%u\n", ndc->tx_table[index]);
> +
> + return offset;
> +}
> +
> +static void netvsc_attrs_init(void)
> +{
> + int i;
> + char buffer[32];
> +
> + for (i = 0; i < VRSS_SEND_TAB_SIZE; i++) {
> + sprintf(buffer, "tx_indirection_table_%02u", i);
> + dev_attr_netvsc_dev_attrs[i].attr.name =
> + kstrdup(buffer, GFP_KERNEL);
> + dev_attr_netvsc_dev_attrs[i].attr.mode = 0444;
> + sysfs_attr_init(&dev_attr_netvsc_dev_attrs[i].attr);
> +
> + dev_attr_netvsc_dev_attrs[i].show = tx_indirection_table_show;
> + dev_attr_netvsc_dev_attrs[i].store = NULL;
> + netvsc_dev_attrs[i] = &dev_attr_netvsc_dev_attrs[i].attr;
> + }
> + netvsc_dev_attrs[VRSS_SEND_TAB_SIZE] = NULL;
> +}
> +
> +static void netvsc_attrs_exit(void)
> +{
> + int i;
> +
> + for (i = 0; i < VRSS_SEND_TAB_SIZE; i++)
> + kfree(dev_attr_netvsc_dev_attrs[i].attr.name);
> +}
> +
> static int netvsc_probe(struct hv_device *dev,
> const struct hv_vmbus_device_id *dev_id)
> {
> @@ -2396,6 +2445,7 @@ static int netvsc_probe(struct hv_device *dev,
> net_device_ctx->msg_enable);
>
> hv_set_drvdata(dev, net);
> + netvsc_attrs_init();
dev_attr_netvsc_dev_attrs is a global array, so it should be initialized
and cleaned up in netvsc_drv_init/exit().
If there are multiple NICs and possible hot add/remove, init/cleaning it in
netvsc_probe/remove() will cause memory leak, and/or use of freed
memory.
Thanks,
- Haiyang
