[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_hash.c b/net/ipv4/fib_hash.c
index 499522f..a15b2f1 100644
--- a/net/ipv4/fib_hash.c
+++ b/net/ipv4/fib_hash.c
@@ -52,6 +52,7 @@
struct hlist_node fn_hash;
struct list_head fn_alias;
__be32 fn_key;
+ struct fib_alias fn_embedded_alias;
};
struct fn_zone {
@@ -193,10 +194,13 @@
kmem_cache_free(fn_hash_kmem, f);
}
-static inline void fn_free_alias(struct fib_alias *fa)
+static inline void fn_free_alias(struct fib_alias *fa, struct fib_node *f)
{
fib_release_info(fa->fa_info);
- kmem_cache_free(fn_alias_kmem, fa);
+ if (fa == &f->fn_embedded_alias)
+ fa->fa_info = NULL;
+ else
+ kmem_cache_free(fn_alias_kmem, fa);
}
static struct fn_zone *
@@ -476,15 +480,12 @@
goto out;
err = -ENOBUFS;
- new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
- if (new_fa == NULL)
- goto out;
new_f = NULL;
if (!f) {
- new_f = kmem_cache_alloc(fn_hash_kmem, GFP_KERNEL);
+ new_f = kmem_cache_zalloc(fn_hash_kmem, GFP_KERNEL);
if (new_f == NULL)
- goto out_free_new_fa;
+ goto out;
INIT_HLIST_NODE(&new_f->fn_hash);
INIT_LIST_HEAD(&new_f->fn_alias);
@@ -492,6 +493,12 @@
f = new_f;
}
+ new_fa = &f->fn_embedded_alias;
+ if (new_fa->fa_info != NULL) {
+ new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
+ if (new_fa == NULL)
+ goto out_free_new_f;
+ }
new_fa->fa_info = fi;
new_fa->fa_tos = tos;
new_fa->fa_type = cfg->fc_type;
@@ -518,8 +525,8 @@
&cfg->fc_nlinfo, 0);
return 0;
-out_free_new_fa:
- kmem_cache_free(fn_alias_kmem, new_fa);
+out_free_new_f:
+ kmem_cache_free(fn_hash_kmem, new_f);
out:
fib_release_info(fi);
return err;
@@ -595,7 +602,7 @@
if (fa->fa_state & FA_S_ACCESSED)
rt_cache_flush(-1);
- fn_free_alias(fa);
+ fn_free_alias(fa, f);
if (kill_fn) {
fn_free_node(f);
fz->fz_nent--;
@@ -631,7 +638,7 @@
fib_hash_genid++;
write_unlock_bh(&fib_hash_lock);
- fn_free_alias(fa);
+ fn_free_alias(fa, f);
found++;
}
}
@@ -750,10 +757,10 @@
void __init fib_hash_init(void)
{
fn_hash_kmem = kmem_cache_create("ip_fib_hash", sizeof(struct fib_node),
- 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+ 0, SLAB_PANIC, NULL);
fn_alias_kmem = kmem_cache_create("ip_fib_alias", sizeof(struct fib_alias),
- 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+ 0, SLAB_PANIC, NULL);
}
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
