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author | Felix Fietkau <nbd@openwrt.org> | 2015-03-12 15:27:44 +0000 |
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committer | Felix Fietkau <nbd@openwrt.org> | 2015-03-12 15:27:44 +0000 |
commit | 074ba4221ed1e14ef5d9d1611bdd49bd10011866 (patch) | |
tree | bbf41a4ce940396451b85bdbea23882e997cc6b2 /target/linux/generic/patches-3.18/080-17-fib_trie-Remove-checks-for-index-tnode_child_length-.patch | |
parent | b585a81ca19c5f17bd33c9925ffa0c9d85072f44 (diff) | |
download | master-187ad058-074ba4221ed1e14ef5d9d1611bdd49bd10011866.tar.gz master-187ad058-074ba4221ed1e14ef5d9d1611bdd49bd10011866.tar.bz2 master-187ad058-074ba4221ed1e14ef5d9d1611bdd49bd10011866.zip |
kernel: backport fib_trie improvements/fixes from 4.0-rc
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@44695 3c298f89-4303-0410-b956-a3cf2f4a3e73
Diffstat (limited to 'target/linux/generic/patches-3.18/080-17-fib_trie-Remove-checks-for-index-tnode_child_length-.patch')
-rw-r--r-- | target/linux/generic/patches-3.18/080-17-fib_trie-Remove-checks-for-index-tnode_child_length-.patch | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/target/linux/generic/patches-3.18/080-17-fib_trie-Remove-checks-for-index-tnode_child_length-.patch b/target/linux/generic/patches-3.18/080-17-fib_trie-Remove-checks-for-index-tnode_child_length-.patch new file mode 100644 index 0000000000..8f7c671ac6 --- /dev/null +++ b/target/linux/generic/patches-3.18/080-17-fib_trie-Remove-checks-for-index-tnode_child_length-.patch @@ -0,0 +1,95 @@ +From: Alexander Duyck <alexander.h.duyck@redhat.com> +Date: Wed, 31 Dec 2014 10:57:02 -0800 +Subject: [PATCH] fib_trie: Remove checks for index >= tnode_child_length + from tnode_get_child + +For some reason the compiler doesn't seem to understand that when we are in +a loop that runs from tnode_child_length - 1 to 0 we don't expect the value +of tn->bits to change. As such every call to tnode_get_child was rerunning +tnode_chile_length which ended up consuming quite a bit of space in the +resultant assembly code. + +I have gone though and verified that in all cases where tnode_get_child +is used we are either winding though a fixed loop from tnode_child_length - +1 to 0, or are in a fastpath case where we are verifying the value by +either checking for any remaining bits after shifting index by bits and +testing for leaf, or by using tnode_child_length. + +size net/ipv4/fib_trie.o +Before: + text data bss dec hex filename + 15506 376 8 15890 3e12 net/ipv4/fib_trie.o + +After: + text data bss dec hex filename + 14827 376 8 15211 3b6b net/ipv4/fib_trie.o + +Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + +--- a/net/ipv4/fib_trie.c ++++ b/net/ipv4/fib_trie.c +@@ -186,8 +186,6 @@ static inline unsigned long tnode_child_ + static inline struct tnode *tnode_get_child(const struct tnode *tn, + unsigned long i) + { +- BUG_ON(i >= tnode_child_length(tn)); +- + return rtnl_dereference(tn->child[i]); + } + +@@ -195,8 +193,6 @@ static inline struct tnode *tnode_get_ch + static inline struct tnode *tnode_get_child_rcu(const struct tnode *tn, + unsigned long i) + { +- BUG_ON(i >= tnode_child_length(tn)); +- + return rcu_dereference_rtnl(tn->child[i]); + } + +@@ -371,7 +367,7 @@ static inline int tnode_full(const struc + */ + static void put_child(struct tnode *tn, unsigned long i, struct tnode *n) + { +- struct tnode *chi = rtnl_dereference(tn->child[i]); ++ struct tnode *chi = tnode_get_child(tn, i); + int isfull, wasfull; + + BUG_ON(i >= tnode_child_length(tn)); +@@ -867,7 +863,7 @@ static struct tnode *fib_find_node(struc + if (IS_LEAF(n)) + break; + +- n = rcu_dereference_rtnl(n->child[index]); ++ n = tnode_get_child_rcu(n, index); + } + + return n; +@@ -934,7 +930,7 @@ static struct list_head *fib_insert_node + } + + tp = n; +- n = rcu_dereference_rtnl(n->child[index]); ++ n = tnode_get_child_rcu(n, index); + } + + l = leaf_new(key); +@@ -1215,7 +1211,7 @@ int fib_table_lookup(struct fib_table *t + cindex = index; + } + +- n = rcu_dereference(n->child[index]); ++ n = tnode_get_child_rcu(n, index); + if (unlikely(!n)) + goto backtrace; + } +@@ -1835,7 +1831,7 @@ static void trie_collect_stats(struct tr + if (n->bits < MAX_STAT_DEPTH) + s->nodesizes[n->bits]++; + +- for (i = 0; i < tnode_child_length(n); i++) { ++ for (i = tnode_child_length(n); i--;) { + if (!rcu_access_pointer(n->child[i])) + s->nullpointers++; + } |