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2011-06-20Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/iwlwifi/iwl-agn-rxon.c drivers/net/wireless/rtlwifi/pci.c net/netfilter/ipvs/ip_vs_core.c
2011-06-17net: rfs: enable RFS before first data packet is receivedEric Dumazet
Le jeudi 16 juin 2011 à 23:38 -0400, David Miller a écrit : > From: Ben Hutchings <bhutchings@solarflare.com> > Date: Fri, 17 Jun 2011 00:50:46 +0100 > > > On Wed, 2011-06-15 at 04:15 +0200, Eric Dumazet wrote: > >> @@ -1594,6 +1594,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) > >> goto discard; > >> > >> if (nsk != sk) { > >> + sock_rps_save_rxhash(nsk, skb->rxhash); > >> if (tcp_child_process(sk, nsk, skb)) { > >> rsk = nsk; > >> goto reset; > >> > > > > I haven't tried this, but it looks reasonable to me. > > > > What about IPv6? The logic in tcp_v6_do_rcv() looks very similar. > > Indeed ipv6 side needs the same fix. > > Eric please add that part and resubmit. And in fact I might stick > this into net-2.6 instead of net-next-2.6 > OK, here is the net-2.6 based one then, thanks ! [PATCH v2] net: rfs: enable RFS before first data packet is received First packet received on a passive tcp flow is not correctly RFS steered. One sock_rps_record_flow() call is missing in inet_accept() But before that, we also must record rxhash when child socket is setup. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Tom Herbert <therbert@google.com> CC: Ben Hutchings <bhutchings@solarflare.com> CC: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@conan.davemloft.net>
2011-06-08tcp: RFC2988bis + taking RTT sample from 3WHS for the passive open sideJerry Chu
This patch lowers the default initRTO from 3secs to 1sec per RFC2988bis. It falls back to 3secs if the SYN or SYN-ACK packet has been retransmitted, AND the TCP timestamp option is not on. It also adds support to take RTT sample during 3WHS on the passive open side, just like its active open counterpart, and uses it, if valid, to seed the initRTO for the data transmission phase. The patch also resets ssthresh to its initial default at the beginning of the data transmission phase, and reduces cwnd to 1 if there has been MORE THAN ONE retransmission during 3WHS per RFC5681. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-24net: convert %p usage to %pKDan Rosenberg
The %pK format specifier is designed to hide exposed kernel pointers, specifically via /proc interfaces. Exposing these pointers provides an easy target for kernel write vulnerabilities, since they reveal the locations of writable structures containing easily triggerable function pointers. The behavior of %pK depends on the kptr_restrict sysctl. If kptr_restrict is set to 0, no deviation from the standard %p behavior occurs. If kptr_restrict is set to 1, the default, if the current user (intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG (currently in the LSM tree), kernel pointers using %pK are printed as 0's. If kptr_restrict is set to 2, kernel pointers using %pK are printed as 0's regardless of privileges. Replacing with 0's was chosen over the default "(null)", which cannot be parsed by userland %p, which expects "(nil)". The supporting code for kptr_restrict and %pK are currently in the -mm tree. This patch converts users of %p in net/ to %pK. Cases of printing pointers to the syslog are not covered, since this would eliminate useful information for postmortem debugging and the reading of the syslog is already optionally protected by the dmesg_restrict sysctl. Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Cc: James Morris <jmorris@namei.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Thomas Graf <tgraf@infradead.org> Cc: Eugene Teo <eugeneteo@kernel.org> Cc: Kees Cook <kees.cook@canonical.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David S. Miller <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Eric Paris <eparis@parisplace.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-18ipv4: Pass explicit destination address to rt_bind_peer().David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-18ipv4: Pass explicit destination address to rt_get_peer().David S. Miller
This will next trickle down to rt_bind_peer(). Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-18ipv4: Make caller provide flowi4 key to inet_csk_route_req().David S. Miller
This way the caller can get at the fully resolved fl4->{daddr,saddr} etc. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-10ipv4: Pass explicit daddr arg to ip_send_reply().David S. Miller
This eliminates an access to rt->rt_src. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-08tcp: Use cork flow info instead of rt->rt_dst in tcp_v4_get_peer()David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-08ipv4: Use inet_csk_route_child_sock() in DCCP and TCP.David S. Miller
Operation order is now transposed, we first create the child socket then we try to hook up the route. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-08tcp: Use cork flow in tcp_v4_connect()David S. Miller
Since this is invoked from inet_stream_connect() the socket is locked and therefore this usage is safe. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-04-28ipv4: Get route daddr from flow key in tcp_v4_connect().David S. Miller
Now that output route lookups update the flow with destination address selection, we can fetch it from fl4->daddr instead of rt->rt_dst Signed-off-by: David S. Miller <davem@davemloft.net>
2011-04-28ipv4: Fetch route saddr from flow key in tcp_v4_connect().David S. Miller
Now that output route lookups update the flow with source address selection, we can fetch it from fl4->saddr instead of rt->rt_src Signed-off-by: David S. Miller <davem@davemloft.net>
2011-04-28inet: add RCU protection to inet->optEric Dumazet
We lack proper synchronization to manipulate inet->opt ip_options Problem is ip_make_skb() calls ip_setup_cork() and ip_setup_cork() possibly makes a copy of ipc->opt (struct ip_options), without any protection against another thread manipulating inet->opt. Another thread can change inet->opt pointer and free old one under us. Use RCU to protect inet->opt (changed to inet->inet_opt). Instead of handling atomic refcounts, just copy ip_options when necessary, to avoid cache line dirtying. We cant insert an rcu_head in struct ip_options since its included in skb->cb[], so this patch is large because I had to introduce a new ip_options_rcu structure. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-04-27ipv4: Sanitize and simplify ip_route_{connect,newports}()David S. Miller
These functions are used together as a unit for route resolution during connect(). They address the chicken-and-egg problem that exists when ports need to be allocated during connect() processing, yet such port allocations require addressing information from the routing code. It's currently more heavy handed than it needs to be, and in particular we allocate and initialize a flow object twice. Let the callers provide the on-stack flow object. That way we only need to initialize it once in the ip_route_connect() call. Later, if ip_route_newports() needs to do anything, it re-uses that flow object as-is except for the ports which it updates before the route re-lookup. Also, describe why this set of facilities are needed and how it works in a big comment. Signed-off-by: David S. Miller <davem@davemloft.net> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
2011-04-22inet: constify ip headers and in6_addrEric Dumazet
Add const qualifiers to structs iphdr, ipv6hdr and in6_addr pointers where possible, to make code intention more obvious. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-02ipv4: Make output route lookup return rtable directly.David S. Miller
Instead of on the stack. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-01ipv4: Can final ip_route_connect() arg to boolean "can_sleep".David S. Miller
Since that's what the current vague "flags" thing means. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-24ipv4: Rearrange how ip_route_newports() gets port keys.David S. Miller
ip_route_newports() is the only place in the entire kernel that cares about the port members in the routing cache entry's lookup flow key. Therefore the only reason we store an entire flow inside of the struct rtentry is for this one special case. Rewrite ip_route_newports() such that: 1) The caller passes in the original port values, so we don't need to use the rth->fl.fl_ip_{s,d}port values to remember them. 2) The lookup flow is constructed by hand instead of being copied from the routing cache entry's flow. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-20tcp: Remove debug macro of TCP_CHECK_TIMERShan Wei
Now, TCP_CHECK_TIMER is not used for debuging, it does nothing. And, it has been there for several years, maybe 6 years. Remove it to keep code clearer. Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-10inetpeer: Abstract address representation further.David S. Miller
Future changes will add caching information, and some of these new elements will be addresses. Since the family is implicit via the ->daddr.family member, replicating the family in ever address we store is entirely redundant. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-24tcp: fix bug in listening_get_next()Eric Dumazet
commit a8b690f98baf9fb19 (tcp: Fix slowness in read /proc/net/tcp) introduced a bug in handling of SYN_RECV sockets. st->offset represents number of sockets found since beginning of listening_hash[st->bucket]. We should not reset st->offset when iterating through syn_table[st->sbucket], or else if more than ~25 sockets (if PAGE_SIZE=4096) are in SYN_RECV state, we exit from listening_get_next() with a too small st->offset Next time we enter tcp_seek_last_pos(), we are not able to seek past already found sockets. Reported-by: PK <runningdoglackey@yahoo.com> CC: Tom Herbert <therbert@google.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-26Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: net/ipv4/fib_frontend.c
2010-12-23tcp: fix listening_get_next()Eric Dumazet
Alexey Vlasov found /proc/net/tcp could sometime loop and display millions of sockets in LISTEN state. In 2.6.29, when we converted TCP hash tables to RCU, we left two sk_next() calls in listening_get_next(). We must instead use sk_nulls_next() to properly detect an end of chain. Reported-by: Alexey Vlasov <renton@renton.name> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-13net: Abstract default ADVMSS behind an accessor.David S. Miller
Make all RTAX_ADVMSS metric accesses go through a new helper function, dst_metric_advmss(). Leave the actual default metric as "zero" in the real metric slot, and compute the actual default value dynamically via a new dst_ops AF specific callback. For stacked IPSEC routes, we use the advmss of the path which preserves existing behavior. Unlike ipv4/ipv6, DecNET ties the advmss to the mtu and thus updates advmss on pmtu updates. This inconsistency in advmss handling results in more raw metric accesses than I wish we ended up with. Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-08Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/ath/ath9k/ar9003_eeprom.c net/llc/af_llc.c
2010-12-01timewait_sock: Create and use getpeer op.David S. Miller
The only thing AF-specific about remembering the timestamp for a time-wait TCP socket is getting the peer. Abstract that behind a new timewait_sock_ops vector. Support for real IPV6 sockets is not filled in yet, but curiously this makes timewait recycling start to work for v4-mapped ipv6 sockets. Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-30inet: Turn ->remember_stamp into ->get_peer in connection AF ops.David S. Miller
Then we can make a completely generic tcp_remember_stamp() that uses ->get_peer() as a helper, minimizing the AF specific code and minimizing the eventual code duplication when we implement the ipv6 side of TW recycling. Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-30inetpeer: Make inet_getpeer() take an inet_peer_adress_t pointer.David S. Miller
And make an inet_getpeer_v4() helper, update callers. Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-30inetpeer: Introduce inet_peer_address_t.David S. Miller
Currently only the v4 aspect is used, but this will change. Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-27netns: Don't leak others' openreq-s in procPavel Emelyanov
The /proc/net/tcp leaks openreq sockets from other namespaces. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-12tcp: Don't change unlocked socket state in tcp_v4_err().David S. Miller
Alexey Kuznetsov noticed a regression introduced by commit f1ecd5d9e7366609d640ff4040304ea197fbc618 ("Revert Backoff [v3]: Revert RTO on ICMP destination unreachable") The RTO and timer modification code added to tcp_v4_err() doesn't check sock_owned_by_user(), which if true means we don't have exclusive access to the socket and therefore cannot modify it's critical state. Just skip this new code block if sock_owned_by_user() is true and eliminate the now superfluous sock_owned_by_user() code block contained within. Reported-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: David S. Miller <davem@davemloft.net> CC: Damian Lukowski <damian@tvk.rwth-aachen.de> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
2010-10-21tproxy: fix hash locking issue when using port redirection in ↵Balazs Scheidler
__inet_inherit_port() When __inet_inherit_port() is called on a tproxy connection the wrong locks are held for the inet_bind_bucket it is added to. __inet_inherit_port() made an implicit assumption that the listener's port number (and thus its bind bucket). Unfortunately, if you're using the TPROXY target to redirect skbs to a transparent proxy that assumption is not true anymore and things break. This patch adds code to __inet_inherit_port() so that it can handle this case by looking up or creating a new bind bucket for the child socket and updates callers of __inet_inherit_port() to gracefully handle __inet_inherit_port() failing. Reported by and original patch from Stephen Buck <stephen.buck@exinda.com>. See http://marc.info/?t=128169268200001&r=1&w=2 for the original discussion. Signed-off-by: KOVACS Krisztian <hidden@balabit.hu> Signed-off-by: Patrick McHardy <kaber@trash.net>
2010-08-31gro: unexport tcp4_gro_receive and tcp4_gro_completeEric Dumazet
tcp4_gro_receive() and tcp4_gro_complete() dont need to be exported. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-07-12inet, inet6: make tcp_sendmsg() and tcp_sendpage() through inet_sendmsg() ↵Changli Gao
and inet_sendpage() a new boolean flag no_autobind is added to structure proto to avoid the autobind calls when the protocol is TCP. Then sock_rps_record_flow() is called int the TCP's sendmsg() and sendpage() pathes. Signed-off-by: Changli Gao <xiaosuo@gmail.com> ---- include/net/inet_common.h | 4 ++++ include/net/sock.h | 1 + include/net/tcp.h | 8 ++++---- net/ipv4/af_inet.c | 15 +++++++++------ net/ipv4/tcp.c | 11 +++++------ net/ipv4/tcp_ipv4.c | 3 +++ net/ipv6/af_inet6.c | 8 ++++---- net/ipv6/tcp_ipv6.c | 3 +++ 8 files changed, 33 insertions(+), 20 deletions(-) Signed-off-by: David S. Miller <davem@davemloft.net>
2010-07-12net/ipv4: EXPORT_SYMBOL cleanupsEric Dumazet
CodingStyle cleanups EXPORT_SYMBOL should immediately follow the symbol declaration. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-26syncookies: add support for ECNFlorian Westphal
Allows use of ECN when syncookies are in effect by encoding ecn_ok into the syn-ack tcp timestamp. While at it, remove a uneeded #ifdef CONFIG_SYN_COOKIES. With CONFIG_SYN_COOKIES=nm want_cookie is ifdef'd to 0 and gcc removes the "if (0)". Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-16inetpeer: restore small inet_peer structuresEric Dumazet
Addition of rcu_head to struct inet_peer added 16bytes on 64bit arches. Thats a bit unfortunate, since old size was exactly 64 bytes. This can be solved, using an union between this rcu_head an four fields, that are normally used only when a refcount is taken on inet_peer. rcu_head is used only when refcnt=-1, right before structure freeing. Add a inet_peer_refcheck() function to check this assertion for a while. We can bring back SLAB_HWCACHE_ALIGN qualifier in kmem cache creation. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-10net-next: remove useless union keywordChangli Gao
remove useless union keyword in rtable, rt6_info and dn_route. Since there is only one member in a union, the union keyword isn't useful. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07tcp: Fix slowness in read /proc/net/tcpTom Herbert
This patch address a serious performance issue in reading the TCP sockets table (/proc/net/tcp). Reading the full table is done by a number of sequential read operations. At each read operation, a seek is done to find the last socket that was previously read. This seek operation requires that the sockets in the table need to be counted up to the current file position, and to count each of these requires taking a lock for each non-empty bucket. The whole algorithm is O(n^2). The fix is to cache the last bucket value, offset within the bucket, and the file position returned by the last read operation. On the next sequential read, the bucket and offset are used to find the last read socket immediately without needing ot scan the previous buckets the table. This algorithm t read the whole table is O(n). The improvement offered by this patch is easily show by performing cat'ing /proc/net/tcp on a machine with a lot of connections. With about 182K connections in the table, I see the following: - Without patch time cat /proc/net/tcp > /dev/null real 1m56.729s user 0m0.214s sys 1m56.344s - With patch time cat /proc/net/tcp > /dev/null real 0m0.894s user 0m0.290s sys 0m0.594s Signed-off-by: Tom Herbert <therbert@google.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-06Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/sfc/net_driver.h drivers/net/sfc/siena.c
2010-06-05syncookies: avoid unneeded tcp header flag double checkFlorian Westphal
caller: if (!th->rst && !th->syn && th->ack) callee: if (!th->ack) make the caller only check for !syn (common for 3whs), and move the !rst / ack test to the callee. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-05syncookies: make v4/v6 synflood warning behaviour the sameFlorian Westphal
both syn_flood_warning functions print a message, but ipv4 version only prints a warning if CONFIG_SYN_COOKIES=y. Make the v4 one behave like the v6 one. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-04rps: tcp: fix rps_sock_flow_table table updatesEric Dumazet
I believe a moderate SYN flood attack can corrupt RFS flow table (rps_sock_flow_table), making RPS/RFS much less effective. Even in a normal situation, server handling short lived sessions suffer from bad steering for the first data packet of a session, if another SYN packet is received for another session. We do following action in tcp_v4_rcv() : sock_rps_save_rxhash(sk, skb->rxhash); We should _not_ do this if sk is a LISTEN socket, as about each packet received on a LISTEN socket has a different rxhash than previous one. -> RPS_NO_CPU markers are spread all over rps_sock_flow_table. Also, it makes sense to protect sk->rxhash field changes with socket lock (We currently can change it even if user thread owns the lock and might use rxhash) This patch moves sock_rps_save_rxhash() to a sock locked section, and only for non LISTEN sockets. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-16net: Introduce sk_route_nocapsEric Dumazet
TCP-MD5 sessions have intermittent failures, when route cache is invalidated. ip_queue_xmit() has to find a new route, calls sk_setup_caps(sk, &rt->u.dst), destroying the sk->sk_route_caps &= ~NETIF_F_GSO_MASK that MD5 desperately try to make all over its way (from tcp_transmit_skb() for example) So we send few bad packets, and everything is fine when tcp_transmit_skb() is called again for this socket. Since ip_queue_xmit() is at a lower level than TCP-MD5, I chose to use a socket field, sk_route_nocaps, containing bits to mask on sk_route_caps. Reported-by: Bhaskar Dutta <bhaskie@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-27net: Make RFS socket operations not be inet specific.David S. Miller
Idea from Eric Dumazet. As for placement inside of struct sock, I tried to choose a place that otherwise has a 32-bit hole on 64-bit systems. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
2010-04-20net: Fix various endianness glitchesEric Dumazet
Sparse can help us find endianness bugs, but we need to make some cleanups to be able to more easily spot real bugs. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-16rfs: Receive Flow SteeringTom Herbert
This patch implements receive flow steering (RFS). RFS steers received packets for layer 3 and 4 processing to the CPU where the application for the corresponding flow is running. RFS is an extension of Receive Packet Steering (RPS). The basic idea of RFS is that when an application calls recvmsg (or sendmsg) the application's running CPU is stored in a hash table that is indexed by the connection's rxhash which is stored in the socket structure. The rxhash is passed in skb's received on the connection from netif_receive_skb. For each received packet, the associated rxhash is used to look up the CPU in the hash table, if a valid CPU is set then the packet is steered to that CPU using the RPS mechanisms. The convolution of the simple approach is that it would potentially allow OOO packets. If threads are thrashing around CPUs or multiple threads are trying to read from the same sockets, a quickly changing CPU value in the hash table could cause rampant OOO packets-- we consider this a non-starter. To avoid OOO packets, this solution implements two types of hash tables: rps_sock_flow_table and rps_dev_flow_table. rps_sock_table is a global hash table. Each entry is just a CPU number and it is populated in recvmsg and sendmsg as described above. This table contains the "desired" CPUs for flows. rps_dev_flow_table is specific to each device queue. Each entry contains a CPU and a tail queue counter. The CPU is the "current" CPU for a matching flow. The tail queue counter holds the value of a tail queue counter for the associated CPU's backlog queue at the time of last enqueue for a flow matching the entry. Each backlog queue has a queue head counter which is incremented on dequeue, and so a queue tail counter is computed as queue head count + queue length. When a packet is enqueued on a backlog queue, the current value of the queue tail counter is saved in the hash entry of the rps_dev_flow_table. And now the trick: when selecting the CPU for RPS (get_rps_cpu) the rps_sock_flow table and the rps_dev_flow table for the RX queue are consulted. When the desired CPU for the flow (found in the rps_sock_flow table) does not match the current CPU (found in the rps_dev_flow table), the current CPU is changed to the desired CPU if one of the following is true: - The current CPU is unset (equal to RPS_NO_CPU) - Current CPU is offline - The current CPU's queue head counter >= queue tail counter in the rps_dev_flow table. This checks if the queue tail has advanced beyond the last packet that was enqueued using this table entry. This guarantees that all packets queued using this entry have been dequeued, thus preserving in order delivery. Making each queue have its own rps_dev_flow table has two advantages: 1) the tail queue counters will be written on each receive, so keeping the table local to interrupting CPU s good for locality. 2) this allows lockless access to the table-- the CPU number and queue tail counter need to be accessed together under mutual exclusion from netif_receive_skb, we assume that this is only called from device napi_poll which is non-reentrant. This patch implements RFS for TCP and connected UDP sockets. It should be usable for other flow oriented protocols. There are two configuration parameters for RFS. The "rps_flow_entries" kernel init parameter sets the number of entries in the rps_sock_flow_table, the per rxqueue sysfs entry "rps_flow_cnt" contains the number of entries in the rps_dev_flow table for the rxqueue. Both are rounded to power of two. The obvious benefit of RFS (over just RPS) is that it achieves CPU locality between the receive processing for a flow and the applications processing; this can result in increased performance (higher pps, lower latency). The benefits of RFS are dependent on cache hierarchy, application load, and other factors. On simple benchmarks, we don't necessarily see improvement and sometimes see degradation. However, for more complex benchmarks and for applications where cache pressure is much higher this technique seems to perform very well. Below are some benchmark results which show the potential benfit of this patch. The netperf test has 500 instances of netperf TCP_RR test with 1 byte req. and resp. The RPC test is an request/response test similar in structure to netperf RR test ith 100 threads on each host, but does more work in userspace that netperf. e1000e on 8 core Intel No RFS or RPS 104K tps at 30% CPU No RFS (best RPS config): 290K tps at 63% CPU RFS 303K tps at 61% CPU RPC test tps CPU% 50/90/99% usec latency Latency StdDev No RFS/RPS 103K 48% 757/900/3185 4472.35 RPS only: 174K 73% 415/993/2468 491.66 RFS 223K 73% 379/651/1382 315.61 Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-11inet: Remove unused send_check length argumentHerbert Xu
inet: Remove unused send_check length argument This patch removes the unused length argument from the send_check function in struct inet_connection_sock_af_ops. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Tested-by: Yinghai <yinghai.lu@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-11tcp: Handle CHECKSUM_PARTIAL for SYNACK packets for IPv4Herbert Xu
tcp: Handle CHECKSUM_PARTIAL for SYNACK packets for IPv4 This patch moves the common code between tcp_v4_send_check and tcp_v4_gso_send_check into a new function __tcp_v4_send_check. It then uses the new function in tcp_v4_send_synack so that it handles CHECKSUM_PARTIAL properly. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Tested-by: Yinghai <yinghai.lu@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>