From 6c59f16f1770481a6ee684720ec55b1e38b3a4b2 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 14 Nov 2024 03:00:12 -0800 Subject: [PATCH] net: netpoll: flush skb pool during cleanup The netpoll subsystem maintains a pool of 32 pre-allocated SKBs per instance, but these SKBs are not freed when the netpoll user is brought down. This leads to memory waste as these buffers remain allocated but unused. Add skb_pool_flush() to properly clean up these SKBs when netconsole is terminated, improving memory efficiency. Signed-off-by: Breno Leitao Link: https://patch.msgid.link/20241114-skb_buffers_v2-v3-2-9be9f52a8b69@debian.org Signed-off-by: Jakub Kicinski --- net/core/netpoll.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 719c9aae845fb..00e1e4a329022 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -531,6 +531,14 @@ static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr) return -1; } +static void skb_pool_flush(struct netpoll *np) +{ + struct sk_buff_head *skb_pool; + + skb_pool = &np->skb_pool; + skb_queue_purge_reason(skb_pool, SKB_CONSUMED); +} + int netpoll_parse_options(struct netpoll *np, char *opt) { char *cur=opt, *delim; @@ -779,10 +787,12 @@ put_noaddr: err = __netpoll_setup(np, ndev); if (err) - goto put; + goto flush; rtnl_unlock(); return 0; +flush: + skb_pool_flush(np); put: DEBUG_NET_WARN_ON_ONCE(np->dev); if (ip_overwritten) @@ -830,6 +840,8 @@ void __netpoll_cleanup(struct netpoll *np) call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info); } else RCU_INIT_POINTER(np->dev->npinfo, NULL); + + skb_pool_flush(np); } EXPORT_SYMBOL_GPL(__netpoll_cleanup); -- 2.39.5