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authorFelix Fietkau <nbd@openwrt.org>2016-02-08 13:38:11 +0000
committerFelix Fietkau <nbd@openwrt.org>2016-02-08 13:38:11 +0000
commit533147beb2c270ac476d6e5d6402f7ce6c3c6a75 (patch)
tree7358830cd678c8ac9554cccdd46d96120cc2256e /package/kernel
parent446d06edac31570d9c68ec2042a969aedd6c01c7 (diff)
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mac80211: improve a-msdu rx performance by avoiding unnecessary data copying
Signed-off-by: Felix Fietkau <nbd@openwrt.org> SVN-Revision: 48673
Diffstat (limited to 'package/kernel')
-rw-r--r--package/kernel/mac80211/patches/333-cfg80211-reuse-existing-page-fragments-in-A-MSDU-rx.patch132
1 files changed, 132 insertions, 0 deletions
diff --git a/package/kernel/mac80211/patches/333-cfg80211-reuse-existing-page-fragments-in-A-MSDU-rx.patch b/package/kernel/mac80211/patches/333-cfg80211-reuse-existing-page-fragments-in-A-MSDU-rx.patch
new file mode 100644
index 0000000000..6e2d0cf5b0
--- /dev/null
+++ b/package/kernel/mac80211/patches/333-cfg80211-reuse-existing-page-fragments-in-A-MSDU-rx.patch
@@ -0,0 +1,132 @@
+From: Felix Fietkau <nbd@openwrt.org>
+Date: Mon, 8 Feb 2016 14:33:19 +0100
+Subject: [PATCH] cfg80211: reuse existing page fragments in A-MSDU rx
+
+This massively reduces data copying and thus improves rx performance
+
+Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+---
+
+--- a/net/wireless/util.c
++++ b/net/wireless/util.c
+@@ -644,23 +644,93 @@ int ieee80211_data_from_8023(struct sk_b
+ }
+ EXPORT_SYMBOL(ieee80211_data_from_8023);
+
++static void
++__frame_add_frag(struct sk_buff *skb, struct page *page,
++ void *ptr, int len, int size)
++{
++ struct skb_shared_info *sh = skb_shinfo(skb);
++ int page_offset;
++
++ atomic_inc(&page->_count);
++ page_offset = ptr - page_address(page);
++ skb_add_rx_frag(skb, sh->nr_frags, page, page_offset, len, size);
++}
++
++static void
++__ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct sk_buff *frame,
++ int offset, int len)
++{
++ struct skb_shared_info *sh = skb_shinfo(skb);
++ const skb_frag_t *frag = &sh->frags[-1];
++ struct page *frag_page;
++ void *frag_ptr;
++ int frag_len, frag_size;
++ int head_size = skb->len - skb->data_len;
++ int cur_len;
++
++ frag_page = virt_to_head_page(skb->head);
++ frag_ptr = skb->data;
++ frag_size = head_size;
++
++ while (offset >= frag_size) {
++ offset -= frag_size;
++ frag++;
++ frag_page = skb_frag_page(frag);
++ frag_ptr = skb_frag_address(frag);
++ frag_size = skb_frag_size(frag);
++ }
++
++ frag_ptr += offset;
++ frag_len = frag_size - offset;
++
++ cur_len = min(len, frag_len);
++
++ __frame_add_frag(frame, frag_page, frag_ptr, cur_len, frag_size);
++ len -= cur_len;
++
++ while (len > 0) {
++ frag++;
++ frag_len = skb_frag_size(frag);
++ cur_len = min(len, frag_len);
++ __frame_add_frag(frame, skb_frag_page(frag),
++ skb_frag_address(frag), cur_len, frag_len);
++ len -= cur_len;
++ }
++}
++
+ static struct sk_buff *
+ __ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen,
+- int offset, int len)
++ int offset, int len, bool reuse_frag)
+ {
+ struct sk_buff *frame;
++ int cur_len = len;
+
+ if (skb->len - offset < len)
+ return NULL;
+
+ /*
++ * When reusing framents, copy some data to the head to simplify
++ * ethernet header handling and speed up protocol header processing
++ * in the stack later.
++ */
++ if (reuse_frag)
++ cur_len = min_t(int, len, 32);
++
++ /*
+ * Allocate and reserve two bytes more for payload
+ * alignment since sizeof(struct ethhdr) is 14.
+ */
+- frame = dev_alloc_skb(hlen + sizeof(struct ethhdr) + 2 + len);
++ frame = dev_alloc_skb(hlen + sizeof(struct ethhdr) + 2 + cur_len);
+
+ skb_reserve(frame, hlen + sizeof(struct ethhdr) + 2);
+- skb_copy_bits(skb, offset, skb_put(frame, len), len);
++ skb_copy_bits(skb, offset, skb_put(frame, cur_len), cur_len);
++
++ len -= cur_len;
++ if (!len)
++ return frame;
++
++ offset += cur_len;
++ __ieee80211_amsdu_copy_frag(skb, frame, offset, len);
+
+ return frame;
+ }
+@@ -676,6 +746,7 @@ void ieee80211_amsdu_to_8023s(struct sk_
+ u8 *payload;
+ int offset = 0, remaining, err;
+ struct ethhdr eth;
++ bool reuse_frag = skb->head_frag && !skb_has_frag_list(skb);
+ bool reuse_skb = false;
+ bool last = false;
+
+@@ -703,12 +774,13 @@ void ieee80211_amsdu_to_8023s(struct sk_
+ offset += sizeof(struct ethhdr);
+ /* reuse skb for the last subframe */
+ last = remaining <= subframe_len + padding;
+- if (!skb_is_nonlinear(skb) && last) {
++ if (!skb_is_nonlinear(skb) && !reuse_frag && last) {
+ skb_pull(skb, offset);
+ frame = skb;
+ reuse_skb = true;
+ } else {
+- frame = __ieee80211_amsdu_copy(skb, hlen, offset, len);
++ frame = __ieee80211_amsdu_copy(skb, hlen, offset, len,
++ reuse_frag);
+ if (!frame)
+ goto purge;
+