From 6f89cffc9add6939d44a6b54cf9a5e77849aa7fd Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Sun, 27 May 2012 14:43:58 +0000 Subject: [PATCH] kernel: add a few patches for avoiding unnecessary skb reallocations - significantly improves ethernet<->wireless performance with mac80211 based drivers SVN-Revision: 31886 --- .../653-disable_netlink_trim.patch | 28 +++++++++++++++++++ .../654-avoid_skb_cow_realloc.patch | 20 +++++++++++++ .../patches-3.3/655-increase_skb_pad.patch | 11 ++++++++ 3 files changed, 59 insertions(+) create mode 100644 target/linux/generic/patches-3.3/653-disable_netlink_trim.patch create mode 100644 target/linux/generic/patches-3.3/654-avoid_skb_cow_realloc.patch create mode 100644 target/linux/generic/patches-3.3/655-increase_skb_pad.patch diff --git a/target/linux/generic/patches-3.3/653-disable_netlink_trim.patch b/target/linux/generic/patches-3.3/653-disable_netlink_trim.patch new file mode 100644 index 0000000000..c6c7c75a9e --- /dev/null +++ b/target/linux/generic/patches-3.3/653-disable_netlink_trim.patch @@ -0,0 +1,28 @@ +--- a/net/netlink/af_netlink.c ++++ b/net/netlink/af_netlink.c +@@ -854,25 +854,7 @@ void netlink_detachskb(struct sock *sk, + + static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation) + { +- int delta; +- + skb_orphan(skb); +- +- delta = skb->end - skb->tail; +- if (delta * 2 < skb->truesize) +- return skb; +- +- if (skb_shared(skb)) { +- struct sk_buff *nskb = skb_clone(skb, allocation); +- if (!nskb) +- return skb; +- kfree_skb(skb); +- skb = nskb; +- } +- +- if (!pskb_expand_head(skb, 0, -delta, allocation)) +- skb->truesize -= delta; +- + return skb; + } + diff --git a/target/linux/generic/patches-3.3/654-avoid_skb_cow_realloc.patch b/target/linux/generic/patches-3.3/654-avoid_skb_cow_realloc.patch new file mode 100644 index 0000000000..dfa98198ed --- /dev/null +++ b/target/linux/generic/patches-3.3/654-avoid_skb_cow_realloc.patch @@ -0,0 +1,20 @@ +--- a/include/linux/skbuff.h ++++ b/include/linux/skbuff.h +@@ -1850,12 +1850,15 @@ static inline int skb_clone_writable(con + static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom, + int cloned) + { ++ unsigned int alloc_headroom = headroom; + int delta = 0; + + if (headroom < NET_SKB_PAD) +- headroom = NET_SKB_PAD; +- if (headroom > skb_headroom(skb)) ++ alloc_headroom = NET_SKB_PAD; ++ if (headroom > skb_headroom(skb) || ++ (cloned && alloc_headroom > skb_headroom(skb))) { + delta = headroom - skb_headroom(skb); ++ } + + if (delta || cloned) + return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0, diff --git a/target/linux/generic/patches-3.3/655-increase_skb_pad.patch b/target/linux/generic/patches-3.3/655-increase_skb_pad.patch new file mode 100644 index 0000000000..5d14daadfa --- /dev/null +++ b/target/linux/generic/patches-3.3/655-increase_skb_pad.patch @@ -0,0 +1,11 @@ +--- a/include/linux/skbuff.h ++++ b/include/linux/skbuff.h +@@ -1558,7 +1558,7 @@ static inline int pskb_network_may_pull( + * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8) + */ + #ifndef NET_SKB_PAD +-#define NET_SKB_PAD max(32, L1_CACHE_BYTES) ++#define NET_SKB_PAD max(48, L1_CACHE_BYTES) + #endif + + extern int ___pskb_trim(struct sk_buff *skb, unsigned int len); -- 2.30.2