[IPV4] FIB_HASH: Reduce memory needs and speedup lookups
Currently, sizeof(struct fib_alias) is 24 or 48 bytes on 32/64 bits
arches.
Because of SLAB_HWCACHE_ALIGN requirement, these are rounded to 32 and
64 bytes respectively.
This patch moves rcu to the end of fib_alias, and conditionally
defines it only for CONFIG_IP_FIB_TRIE.
We also remove SLAB_HWCACHE_ALIGN requirement for fib_alias and
fib_node objects because it is not necessary.
(BTW SLUB currently denies it for objects smaller than
cache_line_size() / 2, but not SLAB)
Finally, sizeof(fib_alias) go back to 16 and 32 bytes.
Then, we can embed one fib_alias on each fib_node, to favor locality.
Most of the time access to the fib_alias will be free because one
cache line contains both the list head (fn_alias) and (one of) the
list element.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_lookup.h b/net/ipv4/fib_lookup.h
index 26ee66d..2c1623d 100644
--- a/net/ipv4/fib_lookup.h
+++ b/net/ipv4/fib_lookup.h
@@ -7,12 +7,14 @@
struct fib_alias {
struct list_head fa_list;
- struct rcu_head rcu;
struct fib_info *fa_info;
u8 fa_tos;
u8 fa_type;
u8 fa_scope;
u8 fa_state;
+#ifdef CONFIG_IP_FIB_TRIE
+ struct rcu_head rcu;
+#endif
};
#define FA_S_ACCESSED 0x01