[PATCH net-next 2/2] net: xsk: make xsk_tx_batch_size tunable

[Jason Xing <kerneljasonxing@gmail.com>]

From: Jason Xing <kernelxing@tencent.com>

In some cases, users probably expect to see xsk_generic_xmit() can
handle more desc at one time. Make it tunable and it would be similar
with how dev_tx_weight works in xsk path.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
 include/net/hotdata.h      | 1 +
 net/core/hotdata.c         | 3 ++-
 net/core/sysctl_net_core.c | 8 ++++++++
 net/xdp/xsk.c              | 4 +---
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/net/hotdata.h b/include/net/hotdata.h
index 2df1e8175a85..862bd168fdd8 100644
--- a/include/net/hotdata.h
+++ b/include/net/hotdata.h
@@ -41,6 +41,7 @@ struct net_hotdata {
 	int			sysctl_skb_defer_max;
 	int			sysctl_mem_pcpu_rsv;
 	int			sysctl_xsk_max_per_socket_budget;
+	int			sysctl_xsk_tx_batch_size;
 };
 
 #define inet_ehash_secret	net_hotdata.tcp_protocol.secret
diff --git a/net/core/hotdata.c b/net/core/hotdata.c
index 5131714eee63..e08fd0ee1b05 100644
--- a/net/core/hotdata.c
+++ b/net/core/hotdata.c
@@ -20,6 +20,7 @@ struct net_hotdata net_hotdata __cacheline_aligned = {
 	.sysctl_max_skb_frags = MAX_SKB_FRAGS,
 	.sysctl_skb_defer_max = 64,
 	.sysctl_mem_pcpu_rsv = SK_MEMORY_PCPU_RESERVE,
-	.sysctl_xsk_max_per_socket_budget = 32
+	.sysctl_xsk_max_per_socket_budget = 32,
+	.sysctl_xsk_tx_batch_size = 32
 };
 EXPORT_SYMBOL(net_hotdata);
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 9f9946b7ffc0..73be2d9e6bab 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -647,6 +647,14 @@ static struct ctl_table net_core_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
+	{
+		.procname	= "xsk_tx_batch_size",
+		.data		= &net_hotdata.sysctl_xsk_tx_batch_size,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
+
 };
 
 static struct ctl_table netns_core_table[] = {
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 95027f964858..4215a40abb69 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -34,8 +34,6 @@
 #include "xdp_umem.h"
 #include "xsk.h"
 
-#define TX_BATCH_SIZE 32
-
 void xsk_set_rx_need_wakeup(struct xsk_buff_pool *pool)
 {
 	if (pool->cached_need_wakeup & XDP_WAKEUP_RX)
@@ -780,8 +778,8 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 
 static int __xsk_generic_xmit(struct sock *sk)
 {
+	u32 max_batch = READ_ONCE(net_hotdata.sysctl_xsk_tx_batch_size);
 	struct xdp_sock *xs = xdp_sk(sk);
-	u32 max_batch = TX_BATCH_SIZE;
 	bool sent_frame = false;
 	struct xdp_desc desc;
 	struct sk_buff *skb;
-- 
2.43.5