From d52d3997f843ffefaa8d8462790ffcaca6c74192 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 22 May 2015 20:56:06 -0700 Subject: ipv6: Create percpu rt6_info After the patch 'ipv6: Only create RTF_CACHE routes after encountering pmtu exception', we need to compensate the performance hit (bouncing dst->__refcnt). Signed-off-by: Martin KaFai Lau Cc: Hannes Frederic Sowa Cc: Steffen Klassert Cc: Julian Anastasov Signed-off-by: David S. Miller --- net/ipv6/route.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 116 insertions(+), 16 deletions(-) (limited to 'net/ipv6/route.c') diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 90c8eaa24565..1a1122a6bbf5 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -165,11 +165,18 @@ static void rt6_uncached_list_flush_dev(struct net *net, struct net_device *dev) } } +static u32 *rt6_pcpu_cow_metrics(struct rt6_info *rt) +{ + return dst_metrics_write_ptr(rt->dst.from); +} + static u32 *ipv6_cow_metrics(struct dst_entry *dst, unsigned long old) { struct rt6_info *rt = (struct rt6_info *)dst; - if (rt->rt6i_flags & RTF_CACHE) + if (rt->rt6i_flags & RTF_PCPU) + return rt6_pcpu_cow_metrics(rt); + else if (rt->rt6i_flags & RTF_CACHE) return NULL; else return dst_cow_metrics_generic(dst, old); @@ -309,10 +316,10 @@ static const struct rt6_info ip6_blk_hole_entry_template = { #endif /* allocate dst with ip6_dst_ops */ -static inline struct rt6_info *ip6_dst_alloc(struct net *net, - struct net_device *dev, - int flags, - struct fib6_table *table) +static struct rt6_info *__ip6_dst_alloc(struct net *net, + struct net_device *dev, + int flags, + struct fib6_table *table) { struct rt6_info *rt = dst_alloc(&net->ipv6.ip6_dst_ops, dev, 0, DST_OBSOLETE_FORCE_CHK, flags); @@ -327,6 +334,34 @@ static inline struct rt6_info *ip6_dst_alloc(struct net *net, return rt; } +static struct rt6_info *ip6_dst_alloc(struct net *net, + struct net_device *dev, + int flags, + struct fib6_table *table) +{ + struct rt6_info *rt = __ip6_dst_alloc(net, dev, flags, table); + + if (rt) { + rt->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, GFP_ATOMIC); + if (rt->rt6i_pcpu) { + int cpu; + + for_each_possible_cpu(cpu) { + struct rt6_info **p; + + p = per_cpu_ptr(rt->rt6i_pcpu, cpu); + /* no one shares rt */ + *p = NULL; + } + } else { + dst_destroy((struct dst_entry *)rt); + return NULL; + } + } + + return rt; +} + static void ip6_dst_destroy(struct dst_entry *dst) { struct rt6_info *rt = (struct rt6_info *)dst; @@ -335,6 +370,9 @@ static void ip6_dst_destroy(struct dst_entry *dst) dst_destroy_metrics_generic(dst); + if (rt->rt6i_pcpu) + free_percpu(rt->rt6i_pcpu); + rt6_uncached_list_del(rt); idev = rt->rt6i_idev; @@ -912,11 +950,11 @@ static struct rt6_info *ip6_rt_cache_alloc(struct rt6_info *ort, * Clone the route. */ - if (ort->rt6i_flags & RTF_CACHE) + if (ort->rt6i_flags & (RTF_CACHE | RTF_PCPU)) ort = (struct rt6_info *)ort->dst.from; - rt = ip6_dst_alloc(dev_net(ort->dst.dev), ort->dst.dev, - 0, ort->rt6i_table); + rt = __ip6_dst_alloc(dev_net(ort->dst.dev), ort->dst.dev, + 0, ort->rt6i_table); if (!rt) return NULL; @@ -943,6 +981,54 @@ static struct rt6_info *ip6_rt_cache_alloc(struct rt6_info *ort, return rt; } +static struct rt6_info *ip6_rt_pcpu_alloc(struct rt6_info *rt) +{ + struct rt6_info *pcpu_rt; + + pcpu_rt = __ip6_dst_alloc(dev_net(rt->dst.dev), + rt->dst.dev, rt->dst.flags, + rt->rt6i_table); + + if (!pcpu_rt) + return NULL; + ip6_rt_copy_init(pcpu_rt, rt); + pcpu_rt->rt6i_protocol = rt->rt6i_protocol; + pcpu_rt->rt6i_flags |= RTF_PCPU; + return pcpu_rt; +} + +/* It should be called with read_lock_bh(&tb6_lock) acquired */ +static struct rt6_info *rt6_get_pcpu_route(struct rt6_info *rt) +{ + struct rt6_info *pcpu_rt, *prev, **p; + + p = this_cpu_ptr(rt->rt6i_pcpu); + pcpu_rt = *p; + + if (pcpu_rt) + goto done; + + pcpu_rt = ip6_rt_pcpu_alloc(rt); + if (!pcpu_rt) { + struct net *net = dev_net(rt->dst.dev); + + pcpu_rt = net->ipv6.ip6_null_entry; + goto done; + } + + prev = cmpxchg(p, NULL, pcpu_rt); + if (prev) { + /* If someone did it before us, return prev instead */ + dst_destroy(&pcpu_rt->dst); + pcpu_rt = prev; + } + +done: + dst_hold(&pcpu_rt->dst); + rt6_dst_from_metrics_check(pcpu_rt); + return pcpu_rt; +} + static struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, int oif, struct flowi6 *fl6, int flags) { @@ -975,11 +1061,13 @@ redo_rt6_select: } } - dst_use(&rt->dst, jiffies); - read_unlock_bh(&table->tb6_lock); if (rt == net->ipv6.ip6_null_entry || (rt->rt6i_flags & RTF_CACHE)) { - goto done; + dst_use(&rt->dst, jiffies); + read_unlock_bh(&table->tb6_lock); + + rt6_dst_from_metrics_check(rt); + return rt; } else if (unlikely((fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH) && !(rt->rt6i_flags & RTF_GATEWAY))) { /* Create a RTF_CACHE clone which will not be @@ -990,6 +1078,9 @@ redo_rt6_select: struct rt6_info *uncached_rt; + dst_use(&rt->dst, jiffies); + read_unlock_bh(&table->tb6_lock); + uncached_rt = ip6_rt_cache_alloc(rt, &fl6->daddr, NULL); dst_release(&rt->dst); @@ -997,13 +1088,22 @@ redo_rt6_select: rt6_uncached_list_add(uncached_rt); else uncached_rt = net->ipv6.ip6_null_entry; + dst_hold(&uncached_rt->dst); return uncached_rt; - } -done: - rt6_dst_from_metrics_check(rt); - return rt; + } else { + /* Get a percpu copy */ + + struct rt6_info *pcpu_rt; + + rt->dst.lastuse = jiffies; + rt->dst.__use++; + pcpu_rt = rt6_get_pcpu_route(rt); + read_unlock_bh(&table->tb6_lock); + + return pcpu_rt; + } } static struct rt6_info *ip6_pol_route_input(struct net *net, struct fib6_table *table, @@ -1147,7 +1247,7 @@ static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie) rt6_dst_from_metrics_check(rt); - if (unlikely(dst->flags & DST_NOCACHE)) + if ((rt->rt6i_flags & RTF_PCPU) || unlikely(dst->flags & DST_NOCACHE)) return rt6_dst_from_check(rt, cookie); else return rt6_check(rt, cookie); -- cgit v1.2.3-59-g8ed1b