[PATCH v4 net-next] udp: introduce __sk_mem_schedule() usage

[PATCH v4 net-next] udp: introduce __sk_mem_schedule() usage

[Jason Xing]

From: Jason Xing <kernelxing@tencent.com>

Keep the accounting schema consistent across different protocols
with __sk_mem_schedule(). Besides, it adjusts a little bit on how
to calculate forward allocated memory compared to before. After
applied this patch, we could avoid receive path scheduling extra
amount of memory.

Link: https://lore.kernel.org/lkml/20230221110344.82818-1-kerneljasonxing@gmail.com/
Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
v4:
1) Move one statement outside of the helper suggested by Paolo Abeni

v3:
1) get rid of inline suggested by Simon Horman

v2:
1) change the title and body message
2) use __sk_mem_schedule() instead suggested by Paolo Abeni
---
 net/ipv4/udp.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index c605d171eb2d..dc8feb54d835 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1531,10 +1531,21 @@ static void busylock_release(spinlock_t *busy)
 		spin_unlock(busy);
 }
 
+static int udp_rmem_schedule(struct sock *sk, int size)
+{
+	int delta;
+
+	delta = size - sk->sk_forward_alloc;
+	if (delta > 0 && !__sk_mem_schedule(sk, delta, SK_MEM_RECV))
+		return -ENOBUFS;
+
+	return 0;
+}
+
 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
 {
 	struct sk_buff_head *list = &sk->sk_receive_queue;
-	int rmem, delta, amt, err = -ENOMEM;
+	int rmem, err = -ENOMEM;
 	spinlock_t *busy = NULL;
 	int size;
 
@@ -1567,16 +1578,10 @@ int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
 		goto uncharge_drop;
 
 	spin_lock(&list->lock);
-	if (size >= sk->sk_forward_alloc) {
-		amt = sk_mem_pages(size);
-		delta = amt << PAGE_SHIFT;
-		if (!__sk_mem_raise_allocated(sk, delta, amt, SK_MEM_RECV)) {
-			err = -ENOBUFS;
-			spin_unlock(&list->lock);
-			goto uncharge_drop;
-		}
-
-		sk->sk_forward_alloc += delta;
+	err = udp_rmem_schedule(sk, size);
+	if (err) {
+		spin_unlock(&list->lock);
+		goto uncharge_drop;
 	}
 
 	sk->sk_forward_alloc -= size;
-- 
2.37.3

Re: [PATCH v4 net-next] udp: introduce __sk_mem_schedule() usage

[Eric Dumazet]

On Wed, Mar 8, 2023 at 3:13 AM Jason Xing <kerneljasonxing@gmail.com> wrote:
>
> From: Jason Xing <kernelxing@tencent.com>
>
> Keep the accounting schema consistent across different protocols
> with __sk_mem_schedule(). Besides, it adjusts a little bit on how
> to calculate forward allocated memory compared to before. After
> applied this patch, we could avoid receive path scheduling extra
> amount of memory.
>
> Link: https://lore.kernel.org/lkml/20230221110344.82818-1-kerneljasonxing@gmail.com/
> Signed-off-by: Jason Xing <kernelxing@tencent.com>
>

Reviewed-by: Eric Dumazet <edumazet@google.com>

Re: [PATCH v4 net-next] udp: introduce __sk_mem_schedule() usage

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed,  8 Mar 2023 10:11:53 +0800 you wrote:
> From: Jason Xing <kernelxing@tencent.com>
> 
> Keep the accounting schema consistent across different protocols
> with __sk_mem_schedule(). Besides, it adjusts a little bit on how
> to calculate forward allocated memory compared to before. After
> applied this patch, we could avoid receive path scheduling extra
> amount of memory.
> 
> [...]

Here is the summary with links:
  - [v4,net-next] udp: introduce __sk_mem_schedule() usage
    https://git.kernel.org/netdev/net-next/c/fd9c31f83441

You are awesome, thank you!
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