From: Eric Dumazet Date: Fri, 18 Jan 2008 11:33:26 +0000 (-0800) Subject: [IPV4] FIB_HASH: Reduce memory needs and speedup lookups X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a6501e080c;p=linux-beck.git [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 Signed-off-by: David S. Miller --- diff --git a/net/ipv4/fib_hash.c b/net/ipv4/fib_hash.c index 499522f3b305..a15b2f1b2721 100644 --- a/net/ipv4/fib_hash.c +++ b/net/ipv4/fib_hash.c @@ -52,6 +52,7 @@ struct fib_node { 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 @@ static inline void fn_free_node(struct fib_node * f) 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 @@ static int fn_hash_insert(struct fib_table *tb, struct fib_config *cfg) 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 @@ static int fn_hash_insert(struct fib_table *tb, struct fib_config *cfg) 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 @@ static int fn_hash_insert(struct fib_table *tb, struct fib_config *cfg) &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 @@ static int fn_hash_delete(struct fib_table *tb, struct fib_config *cfg) 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 @@ static int fn_flush_list(struct fn_zone *fz, int idx) fib_hash_genid++; write_unlock_bh(&fib_hash_lock); - fn_free_alias(fa); + fn_free_alias(fa, f); found++; } } @@ -750,10 +757,10 @@ static int fn_hash_dump(struct fib_table *tb, struct sk_buff *skb, struct netlin 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 26ee66d78c18..2c1623d2768b 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