Hi,Agree.
Po Liu <po.liu@xxxxxxx> writes:
IEEE Std 802.1Qbu standard defined the frame preemption of port
traffic classes. This patch introduce a method to set traffic
classes preemption. Add a parameter 'preemption' in struct
ethtool_link_settings. The value will be translated to a binary,
each bit represent a traffic class. Bit "1" means preemptable
traffic class. Bit "0" means express traffic class. MSB represent
high number traffic class.
I think that we should keep the concept of 'traffic classes' outside of
ethtool. Ethtool should only care about queues (or similar concepts).
And unless I am missing something here, what you mean by 'traffic class'
here is really a hardware queue.
If hardware support the frame preemption, driver could set the
ethernet device with hw_features and features with NETIF_F_PREEMPTION
when initializing the port driver.
User can check the feature 'tx-preemption' by command 'ethtool -k
devname'. If hareware set preemption feature. The property would
be a fixed value 'on' if hardware support the frame preemption.
Feature would show a fixed value 'off' if hardware don't support
the frame preemption.
Command 'ethtool devname' and 'ethtool -s devname preemption N'
would show/set which traffic classes are frame preemptable.
Port driver would implement the frame preemption in the function
get_link_ksettings() and set_link_ksettings() in the struct ethtool_ops.
Signed-off-by: Po Liu <Po.Liu@xxxxxxx>
---
include/linux/netdev_features.h | 5 ++++-
include/uapi/linux/ethtool.h | 5 ++++-
net/core/ethtool.c | 1 +
3 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h
index 4b19c544c59a..299750a8b414 100644
--- a/include/linux/netdev_features.h
+++ b/include/linux/netdev_features.h
@@ -80,6 +80,7 @@ enum {
NETIF_F_GRO_HW_BIT, /* Hardware Generic receive offload */
NETIF_F_HW_TLS_RECORD_BIT, /* Offload TLS record */
+ NETIF_F_HW_PREEMPTION_BIT, /* Hardware TC frame preemption */
/*
* Add your fresh new feature above and remember to update
@@ -150,6 +151,7 @@ enum {
#define NETIF_F_GSO_UDP_L4 __NETIF_F(GSO_UDP_L4)
#define NETIF_F_HW_TLS_TX __NETIF_F(HW_TLS_TX)
#define NETIF_F_HW_TLS_RX __NETIF_F(HW_TLS_RX)
+#define NETIF_F_PREEMPTION __NETIF_F(HW_PREEMPTION)
/* Finds the next feature with the highest number of the range of start till 0.
*/
@@ -175,7 +177,8 @@ static inline int find_next_netdev_feature(u64 feature, unsigned long start)
/* Features valid for ethtool to change */
/* = all defined minus driver/device-class-related */
#define NETIF_F_NEVER_CHANGE (NETIF_F_VLAN_CHALLENGED | \
- NETIF_F_LLTX | NETIF_F_NETNS_LOCAL)
+ NETIF_F_LLTX | NETIF_F_NETNS_LOCAL | \
+ NETIF_F_PREEMPTION)
/* remember that ((t)1 << t_BITS) is undefined in C99 */
#define NETIF_F_ETHTOOL_BITS ((__NETIF_F_BIT(NETDEV_FEATURE_COUNT - 1) | \
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index d4591792f0b4..12ffb34afbfa 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -1776,6 +1776,8 @@ enum ethtool_reset_flags {
};
#define ETH_RESET_SHARED_SHIFT 16
+/* Disable preemtion. */
+#define PREEMPTION_DISABLE 0x0
/**
* struct ethtool_link_settings - link control and status
@@ -1886,7 +1888,8 @@ struct ethtool_link_settings {
__s8 link_mode_masks_nwords;
__u8 transceiver;
__u8 reserved1[3];
- __u32 reserved[7];
+ __u32 preemption;
+ __u32 reserved[6];
__u32 link_mode_masks[0];
/* layout of link_mode_masks fields:
* __u32 map_supported[link_mode_masks_nwords];
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index cd9bc67381b2..6ffcd8a602b8 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -111,6 +111,7 @@ static const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN]
[NETIF_F_HW_TLS_RECORD_BIT] = "tls-hw-record",
[NETIF_F_HW_TLS_TX_BIT] = "tls-hw-tx-offload",
[NETIF_F_HW_TLS_RX_BIT] = "tls-hw-rx-offload",
+ [NETIF_F_HW_PREEMPTION_BIT] = "tx-preemption",
};
static const char
--
2.17.1