On 2021/10/14 21:58, Eric Dumazet wrote:
On 10/14/21 4:39 AM, Guangbin Huang wrote:
From: Hao Chen <chenhao288@xxxxxxxxxxxxx>
Add support for ethtool to set/get tx copybreak buf size.
What is the unit ?
Frankly, having to size the 'buffer' based on number of slots in TX ring buffer
is not good.
What happens later when/if ethtool -G tx xxxxx' is trying
to change number of slots ?
The 'tx copybreak' should instead give a number of bytes per TX ring slot.
Eg, 128 or 256 bytes.
This is very similar to what drivers using net/core/tso.c do.
They usually use TSO_HEADER_SIZE for this.
Hi Eric,
The unit is bytes.
Tx copybreak buf is a queue based tx shared bounce buffer and it is allocated
based on page size, not based on slot numbers. When the len of xmitted skb is
below tx_copybreak, tx copybreak buf will share buffer of specific size(slot size)
for tx to memcpy the small packet.
So, what you mentioned seems not related to this patch.
Signed-off-by: Hao Chen <chenhao288@xxxxxxxxxxxxx>
Signed-off-by: Guangbin Huang <huangguangbin2@xxxxxxxxxx>
---
include/uapi/linux/ethtool.h | 1 +
net/ethtool/common.c | 1 +
net/ethtool/ioctl.c | 1 +
3 files changed, 3 insertions(+)
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index a2223b685451..7bc4b8def12c 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -231,6 +231,7 @@ enum tunable_id {
ETHTOOL_RX_COPYBREAK,
ETHTOOL_TX_COPYBREAK,
ETHTOOL_PFC_PREVENTION_TOUT, /* timeout in msecs */
+ ETHTOOL_TX_COPYBREAK_BUF_SIZE,
/*
* Add your fresh new tunable attribute above and remember to update
* tunable_strings[] in net/ethtool/common.c
diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index c63e0739dc6a..0c5210015911 100644
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -89,6 +89,7 @@ tunable_strings[__ETHTOOL_TUNABLE_COUNT][ETH_GSTRING_LEN] = {
[ETHTOOL_RX_COPYBREAK] = "rx-copybreak",
[ETHTOOL_TX_COPYBREAK] = "tx-copybreak",
[ETHTOOL_PFC_PREVENTION_TOUT] = "pfc-prevention-tout",
+ [ETHTOOL_TX_COPYBREAK_BUF_SIZE] = "tx-copybreak-buf-size",
};
const char
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index bf6e8c2f9bf7..617ebc4183d9 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -2383,6 +2383,7 @@ static int ethtool_tunable_valid(const struct ethtool_tunable *tuna)
switch (tuna->id) {
case ETHTOOL_RX_COPYBREAK:
case ETHTOOL_TX_COPYBREAK:
+ case ETHTOOL_TX_COPYBREAK_BUF_SIZE:
if (tuna->len != sizeof(u32) ||
tuna->type_id != ETHTOOL_TUNABLE_U32)
return -EINVAL;
.
