From 87fb4b7b533073eeeaed0b6bf7c2328995f6c075 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 13 Oct 2011 07:28:54 +0000 Subject: net: more accurate skb truesize skb truesize currently accounts for sk_buff struct and part of skb head. kmalloc() roundings are also ignored. Considering that skb_shared_info is larger than sk_buff, its time to take it into account for better memory accounting. This patch introduces SKB_TRUESIZE(X) macro to centralize various assumptions into a single place. At skb alloc phase, we put skb_shared_info struct at the exact end of skb head, to allow a better use of memory (lowering number of reallocations), since kmalloc() gives us power-of-two memory blocks. Unless SLUB/SLUB debug is active, both skb->head and skb_shared_info are aligned to cache lines, as before. Note: This patch might trigger performance regressions because of misconfigured protocol stacks, hitting per socket or global memory limits that were previously not reached. But its a necessary step for a more accurate memory accounting. Signed-off-by: Eric Dumazet CC: Andi Kleen CC: Ben Hutchings Signed-off-by: David S. Miller --- net/iucv/af_iucv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/iucv') diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index c39f3a4..274d150 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -1819,7 +1819,7 @@ static void iucv_callback_rx(struct iucv_path *path, struct iucv_message *msg) goto save_message; len = atomic_read(&sk->sk_rmem_alloc); - len += iucv_msg_length(msg) + sizeof(struct sk_buff); + len += SKB_TRUESIZE(iucv_msg_length(msg)); if (len > sk->sk_rcvbuf) goto save_message; -- cgit v1.1