Commit 221a9c1d authored by Breno Leitao's avatar Breno Leitao Committed by Jakub Kicinski
Browse files

net: netpoll: Individualize the skb pool 



The current implementation of the netpoll system uses a global skb
pool, which can lead to inefficient memory usage and
waste when targets are disabled or no longer in use.

This can result in a significant amount of memory being unnecessarily
allocated and retained, potentially causing performance issues and
limiting the availability of resources for other system components.

Modify the netpoll system to assign a skb pool to each target instead of
using a global one.

This approach allows for more fine-grained control over memory
allocation and deallocation, ensuring that resources are only allocated
and retained as needed.

Signed-off-by: default avatarBreno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20241114-skb_buffers_v2-v3-1-9be9f52a8b69@debian.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 11ee317d

include/linux/netpoll.h

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ struct netpoll { 
	bool ipv6;

	u16 local_port, remote_port;

	u8 remote_mac[ETH_ALEN];

	struct sk_buff_head skb_pool;

};



struct netpoll_info {

net/core/netpoll.c

+13 −18
Original line number Diff line number Diff line
@@ -45,9 +45,6 @@ 


#define MAX_UDP_CHUNK 1460

#define MAX_SKBS 32



static struct sk_buff_head skb_pool;



#define USEC_PER_POLL	50



#define MAX_SKB_SIZE							\
@@ -234,20 +231,23 @@ void netpoll_poll_enable(struct net_device *dev) 
		up(&ni->dev_lock);

}



static void refill_skbs(void)

static void refill_skbs(struct netpoll *np)

{

	struct sk_buff_head *skb_pool;

	struct sk_buff *skb;

	unsigned long flags;



	spin_lock_irqsave(&skb_pool.lock, flags);

	while (skb_pool.qlen < MAX_SKBS) {

	skb_pool = &np->skb_pool;



	spin_lock_irqsave(&skb_pool->lock, flags);

	while (skb_pool->qlen < MAX_SKBS) {

		skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);

		if (!skb)

			break;



		__skb_queue_tail(&skb_pool, skb);

		__skb_queue_tail(skb_pool, skb);

	}

	spin_unlock_irqrestore(&skb_pool.lock, flags);

	spin_unlock_irqrestore(&skb_pool->lock, flags);

}



static void zap_completion_queue(void)
@@ -284,12 +284,12 @@ static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve) 
	struct sk_buff *skb;



	zap_completion_queue();

	refill_skbs();

	refill_skbs(np);

repeat:



	skb = alloc_skb(len, GFP_ATOMIC);

	if (!skb)

		skb = skb_dequeue(&skb_pool);

		skb = skb_dequeue(&np->skb_pool);



	if (!skb) {

		if (++count < 10) {
@@ -673,6 +673,8 @@ int netpoll_setup(struct netpoll *np) 
	struct in_device *in_dev;

	int err;



	skb_queue_head_init(&np->skb_pool);



	rtnl_lock();

	if (np->dev_name[0]) {

		struct net *net = current->nsproxy->net_ns;
@@ -773,7 +775,7 @@ int netpoll_setup(struct netpoll *np) 
	}



	/* fill up the skb queue */

	refill_skbs();

	refill_skbs(np);



	err = __netpoll_setup(np, ndev);

	if (err)
@@ -792,13 +794,6 @@ int netpoll_setup(struct netpoll *np) 
}

EXPORT_SYMBOL(netpoll_setup);



static int __init netpoll_init(void)

{

	skb_queue_head_init(&skb_pool);

	return 0;

}

core_initcall(netpoll_init);



static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)

{

	struct netpoll_info *npinfo =