| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 7 Jun 2013 09:48:33 -0500
From: Shawn Bohrer <sbohrer@...advisors.com>
To: Eric Dumazet <eric.dumazet@...il.com>
Cc: netdev@...r.kernel.org, davem@...emloft.net
Subject: Re: Performance regression from routing cache removal?
On Thu, Jun 06, 2013 at 05:35:01PM -0700, Eric Dumazet wrote:
> On Wed, 2013-06-05 at 13:52 -0700, Eric Dumazet wrote:
>
> > It can be easily done, with a threshold :
> >
> > Above say 4 multicast addresses in the mc_list, allocate a hash table
> > and populate it.
>
> Please try the following (untested) patch :
>
> include/linux/igmp.h | 1
> include/linux/inetdevice.h | 5 ++
> net/ipv4/igmp.c | 73 +++++++++++++++++++++++++++++++++--
> 3 files changed, 76 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/igmp.h b/include/linux/igmp.h
> index 7f2bf15..e3362b5 100644
> --- a/include/linux/igmp.h
> +++ b/include/linux/igmp.h
> @@ -84,6 +84,7 @@ struct ip_mc_list {
> struct ip_mc_list *next;
> struct ip_mc_list __rcu *next_rcu;
> };
> + struct ip_mc_list __rcu *next_hash;
> struct timer_list timer;
> int users;
> atomic_t refcnt;
> diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
> index ea1e3b8..b99cd23 100644
> --- a/include/linux/inetdevice.h
> +++ b/include/linux/inetdevice.h
> @@ -50,12 +50,17 @@ struct ipv4_devconf {
> DECLARE_BITMAP(state, IPV4_DEVCONF_MAX);
> };
>
> +#define MC_HASH_SZ_LOG 9
> +
> struct in_device {
> struct net_device *dev;
> atomic_t refcnt;
> int dead;
> struct in_ifaddr *ifa_list; /* IP ifaddr chain */
> +
> struct ip_mc_list __rcu *mc_list; /* IP multicast filter chain */
> + struct ip_mc_list __rcu * __rcu *mc_hash;
> +
> int mc_count; /* Number of installed mcasts */
> spinlock_t mc_tomb_lock;
> struct ip_mc_list *mc_tomb;
> diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
> index 450f625..9c60482 100644
> --- a/net/ipv4/igmp.c
> +++ b/net/ipv4/igmp.c
> @@ -1217,6 +1217,56 @@ static void igmp_group_added(struct ip_mc_list *im)
> * Multicast list managers
> */
>
> +static u32 ip_mc_hash(const struct ip_mc_list *im)
> +{
> + return hash_32((u32)im->multiaddr, MC_HASH_SZ_LOG);
> +}
> +
> +static void ip_mc_hash_add(struct in_device *in_dev,
> + struct ip_mc_list *im)
> +{
> + struct ip_mc_list __rcu **mc_hash;
> + u32 hash;
> +
> + mc_hash = rtnl_dereference(in_dev->mc_hash);
> + if (mc_hash) {
> + hash = ip_mc_hash(im);
> + im->next_hash = rtnl_dereference(mc_hash[hash]);
> + rcu_assign_pointer(mc_hash[hash], im);
> + } else if (in_dev->mc_count >= 4) {
> + mc_hash = kzalloc(sizeof(struct ip_mc_list *) << MC_HASH_SZ_LOG,
> + GFP_KERNEL);
> + if (mc_hash) {
> + struct ip_mc_list *aux = rtnl_dereference(in_dev->mc_list);
> +
> + while (aux) {
> + hash = ip_mc_hash(aux);
> +
> + aux->next_hash = rcu_dereference_protected(mc_hash[hash], 1);
> + RCU_INIT_POINTER(mc_hash[hash], aux);
> + aux = rtnl_dereference(aux->next_rcu);
> + }
> + rcu_assign_pointer(in_dev->mc_hash, mc_hash);
> + }
> + }
> +}
> +
> +static void ip_mc_hash_remove(struct in_device *in_dev,
> + struct ip_mc_list *im)
> +{
> + struct ip_mc_list __rcu **mc_hash = rtnl_dereference(in_dev->mc_hash);
> + struct ip_mc_list *aux;
> + unsigned int hash;
> +
> + if (!mc_hash)
> + return;
> + hash = ip_mc_hash(im);
> + mc_hash += hash;
> + while ((aux = rtnl_dereference(*mc_hash)) != im)
> + mc_hash = &aux->next_hash;
> + *mc_hash = im->next_hash;
> +}
> +
>
> /*
> * A socket has joined a multicast group on device dev.
> @@ -1258,6 +1308,8 @@ void ip_mc_inc_group(struct in_device *in_dev, __be32 addr)
> in_dev->mc_count++;
> rcu_assign_pointer(in_dev->mc_list, im);
>
> + ip_mc_hash_add(in_dev, im);
> +
> #ifdef CONFIG_IP_MULTICAST
> igmpv3_del_delrec(in_dev, im->multiaddr);
> #endif
> @@ -1314,6 +1366,7 @@ void ip_mc_dec_group(struct in_device *in_dev, __be32 addr)
> ip = &i->next_rcu) {
> if (i->multiaddr == addr) {
> if (--i->users == 0) {
> + ip_mc_hash_remove(in_dev, i);
> *ip = i->next_rcu;
> in_dev->mc_count--;
> igmp_group_dropped(i);
> @@ -1431,6 +1484,7 @@ void ip_mc_destroy_dev(struct in_device *in_dev)
> ip_mc_clear_src(i);
> ip_ma_put(i);
> }
> + kfree(in_dev->mc_hash);
> }
>
> /* RTNL is locked */
> @@ -2321,12 +2375,25 @@ void ip_mc_drop_socket(struct sock *sk)
> int ip_check_mc_rcu(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u16 proto)
> {
> struct ip_mc_list *im;
> + struct ip_mc_list __rcu **mc_hash;
> struct ip_sf_list *psf;
> int rv = 0;
>
> - for_each_pmc_rcu(in_dev, im) {
> - if (im->multiaddr == mc_addr)
> - break;
> + mc_hash = rcu_dereference(in_dev->mc_hash);
> + if (mc_hash) {
> + u32 hash = hash_32((u32)mc_addr, MC_HASH_SZ_LOG);
> +
> + for (im = rcu_dereference(mc_hash[hash]);
> + im != NULL;
> + im = rcu_dereference(im->next_hash)) {
> + if (im->multiaddr == mc_addr)
> + break;
> + }
> + } else {
> + for_each_pmc_rcu(in_dev, im) {
> + if (im->multiaddr == mc_addr)
> + break;
> + }
> }
> if (im && proto == IPPROTO_IGMP) {
> rv = 1;
>
>
Thanks Eric! I ran this patch last night and it greatly improves the
multicast receive performance on 3.10-rc4. 3.10 may still be 1-2us
slower than 3.4 but it is a little hard for me to tell at the moment
since it looks like there is a mmapped I/O regression in 3.10 that I
also need to track down.
--
Shawn
--
---------------------------------------------------------------
This email, along with any attachments, is confidential. If you
believe you received this message in error, please contact the
sender immediately and delete all copies of the message.
Thank you.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists