diff options
Diffstat (limited to 'target/linux/generic/patches-3.18/656-skb_reduce_truesize-helper.patch')
| -rw-r--r-- | target/linux/generic/patches-3.18/656-skb_reduce_truesize-helper.patch | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/target/linux/generic/patches-3.18/656-skb_reduce_truesize-helper.patch b/target/linux/generic/patches-3.18/656-skb_reduce_truesize-helper.patch new file mode 100644 index 0000000..b326a8b --- /dev/null +++ b/target/linux/generic/patches-3.18/656-skb_reduce_truesize-helper.patch @@ -0,0 +1,41 @@ +From 4593a806e31119c5bd3faa00c7210ad862d515af Mon Sep 17 00:00:00 2001 +From: Dave Taht <dave.taht@bufferbloat.net> +Date: Mon, 31 Dec 2012 10:02:21 -0800 +Subject: [PATCH 3/7] skb_reduce_truesize: helper function for shrinking skbs + whenever needed + +On embedded devices in particular, large queues of small packets from the rx +path with a large truesize can exist. Reducing their size can reduce +memory pressure. skb_reduce_truesize is a helper function for doing this, +when needed. +--- + include/linux/skbuff.h | 18 ++++++++++++++++++ + 1 file changed, 18 insertions(+) + +--- a/include/linux/skbuff.h ++++ b/include/linux/skbuff.h +@@ -2068,6 +2068,24 @@ static inline void pskb_trim_unique(stru + BUG_ON(err); + } + ++/* ++ * Caller wants to reduce memory needs before queueing skb ++ * The (expensive) copy should not be be done in fast path. ++ */ ++static inline struct sk_buff *skb_reduce_truesize(struct sk_buff *skb) ++{ ++ if (skb->truesize > 2 * SKB_TRUESIZE(skb->len)) { ++ struct sk_buff *nskb; ++ nskb = skb_copy_expand(skb, skb_headroom(skb), 0, ++ GFP_ATOMIC | __GFP_NOWARN); ++ if (nskb) { ++ __kfree_skb(skb); ++ skb = nskb; ++ } ++ } ++ return skb; ++} ++ + /** + * skb_orphan - orphan a buffer + * @skb: buffer to orphan |