Increase fragmentation hash bucket size to 1024 from old 64 elems.
After we increased the frag mem limits commit c2a93660 (net: increase
fragment memory usage limits) the hash size of 64 elements is simply
too small. Also considering the mem limit is per netns and the hash
table is shared for all netns.
For the embedded people, note that this increase will change the hash
table/array from using approx 1 Kbytes to 16 Kbytes.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements per hash bucket locking for the frag queue
hash. This removes two write locks, and the only remaining write
lock is for protecting hash rebuild. This essentially reduce the
readers-writer lock to a rebuild lock.
This patch is part of "net: frag performance followup"
http://thread.gmane.org/gmane.linux.network/263644
of which two patches have already been accepted:
Same test setup as previous:
(http://thread.gmane.org/gmane.linux.network/257155)
Two 10G interfaces, on seperate NUMA nodes, are under-test, and uses
Ethernet flow-control. A third interface is used for generating the
DoS attack (with trafgen).
Notice, I have changed the frag DoS generator script to be more
efficient/deadly. Before it would only hit one RX queue, now its
sending packets causing multi-queue RX, due to "better" RX hashing.
Test types summary (netperf UDP_STREAM):
Test-20G64K == 2x10G with 65K fragments
Test-20G3F == 2x10G with 3x fragments (3*1472 bytes)
Test-20G64K+DoS == Same as 20G64K with frag DoS
Test-20G3F+DoS == Same as 20G3F with frag DoS
Test-20G64K+MQ == Same as 20G64K with Multi-Queue frag DoS
Test-20G3F+MQ == Same as 20G3F with Multi-Queue frag DoS
When I rebased this-patch(03) (on top of net-next commit a210576c) and
removed the _bh spinlock, I saw a performance regression. BUT this
was caused by some unrelated change in-between. See tests below.
Test (A) is what I reported before for patch-02, accepted in commit 1b5ab0de.
Test (B) verifying-retest of commit 1b5ab0de corrospond to patch-02.
Test (C) is what I reported before for this-patch
Test (D) is net-next master HEAD (commit a210576c), which reveals some
(unknown) performance regression (compared against test (B)).
Test (D) function as a new base-test.
Performance table summary (in Mbit/s):
(#) Test-type: 20G64K 20G3F 20G64K+DoS 20G3F+DoS 20G64K+MQ 20G3F+MQ
---------- ------- ------- ---------- --------- -------- -------
(A) Patch-02 : 18848.7 13230.1 4103.04 5310.36 130.0 440.2
(B) 1b5ab0de : 18841.5 13156.8 4101.08 5314.57 129.0 424.2
(C) Patch-03v1: 18838.0 13490.5 4405.11 6814.72 196.6 461.6
(D) a210576c : 18321.5 11250.4 3635.34 5160.13 119.1 405.2
(E) with _bh : 17247.3 11492.6 3994.74 6405.29 166.7 413.6
(F) without bh: 17471.3 11298.7 3818.05 6102.11 165.7 406.3
Test (E) and (F) is this-patch(03), with(V1) and without(V2) the _bh spinlocks.
I cannot explain the slow down for 20G64K (but its an artificial
"lab-test" so I'm not worried). But the other results does show
improvements. And test (E) "with _bh" version is slightly better.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Eric Dumazet <edumazet@google.com>
----
V2:
- By analysis from Hannes Frederic Sowa and Eric Dumazet, we don't
need the spinlock _bh versions, as Netfilter currently does a
local_bh_disable() before entering inet_fragment.
- Fold-in desc from cover-mail
V3:
- Drop the chain_len counter per hash bucket.
Signed-off-by: David S. Miller <davem@davemloft.net>
Move the protection of netns_frags.nqueues updates under the LRU_lock,
instead of the write lock. As they are located on the same cacheline,
and this is also needed when transitioning to use per hash bucket locking.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch introduces a constant limit of the fragment queue hash
table bucket list lengths. Currently the limit 128 is choosen somewhat
arbitrary and just ensures that we can fill up the fragment cache with
empty packets up to the default ip_frag_high_thresh limits. It should
just protect from list iteration eating considerable amounts of cpu.
If we reach the maximum length in one hash bucket a warning is printed.
This is implemented on the caller side of inet_frag_find to distinguish
between the different users of inet_fragment.c.
I dropped the out of memory warning in the ipv4 fragment lookup path,
because we already get a warning by the slab allocator.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jesper Dangaard Brouer <jbrouer@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Dave Jones reported a lockdep splat occurring in IP defrag code.
commit 6d7b857d54 (net: use lib/percpu_counter API for
fragmentation mem accounting) added a possible deadlock.
Because percpu_counter_sum_positive() needs to acquire
a lock that can be used from softirq, we need to disable BH
in sum_frag_mem_limit()
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Updating the fragmentation queues LRU (Least-Recently-Used) list,
required taking the hash writer lock. However, the LRU list isn't
tied to the hash at all, so we can use a separate lock for it.
Original-idea-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace the per network namespace shared atomic "mem" accounting
variable, in the fragmentation code, with a lib/percpu_counter.
Getting percpu_counter to scale to the fragmentation code usage
requires some tweaks.
At first view, percpu_counter looks superfast, but it does not
scale on multi-CPU/NUMA machines, because the default batch size
is too small, for frag code usage. Thus, I have adjusted the
batch size by using __percpu_counter_add() directly, instead of
percpu_counter_sub() and percpu_counter_add().
The batch size is increased to 130.000, based on the largest 64K
fragment memory usage. This does introduce some imprecise
memory accounting, but its does not need to be strict for this
use-case.
It is also essential, that the percpu_counter, does not
share cacheline with other writers, to make this scale.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change is primarily a preparation to ease the extension of memory
limit tracking.
The change does reduce the number atomic operation, during freeing of
a frag queue. This does introduce a some performance improvement, as
these atomic operations are at the core of the performance problems
seen on NUMA systems.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fragmentation code cacheline adjusting of struct inet_frag_queue.
Take advantage of the size of struct timer_list, and move all but
spinlock_t lock, below the timer struct. On 64-bit 'lru_list',
'list' and 'refcnt', fits exactly into the next cacheline, and a
new cacheline starts at 'fragments'.
The netns_frags *net pointer is moved to the end of the struct,
because its used in a compare, with "next/close-by" elements of
which this struct is embedded into.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The globally shared rwlock, of struct inet_frags, shares
cacheline with the 'rnd' number, which is used by the hash
calculations. Fix this, as this obviously is a bad idea, as
unnecessary cache-misses will occur when accessing the 'rnd'
number.
Also small note that, moving function ptr (*match) up in struct,
is to avoid it lands on the next cacheline (on 64-bit).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This small cacheline adjustment of struct netns_frags improves
performance significantly for the fragmentation code.
Struct members 'lru_list' and 'mem' are both hot elements, and it
hurts performance, due to cacheline bouncing at every call point,
when they share a cacheline. Also notice, how mem is placed
together with 'high_thresh' and 'low_thresh', as they are used in
the compare operations together.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
IPv4 conntrack defragments incoming packet at the PRE_ROUTING hook and
(in case of forwarded packets) refragments them at POST_ROUTING
independent of the IP_DF flag. Refragmentation uses the dst_mtu() of
the local route without caring about the original fragment sizes,
thereby breaking PMTUD.
This patch fixes this by keeping track of the largest received fragment
with IP_DF set and generates an ICMP fragmentation required error during
refragmentation if that size exceeds the MTU.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
- match() method returns a boolean
- return (A && B && C && D) -> return A && B && C && D
- fix indentation
Signed-off-by: Eric Dumazet <edumazet@google.com>
add fast path for in-order fragments
As the fragments are sent in order in most of OSes, such as Windows, Darwin and
FreeBSD, it is likely the new fragments are at the end of the inet_frag_queue.
In the fast path, we check if the skb at the end of the inet_frag_queue is the
prev we expect.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
----
include/net/inet_frag.h | 1 +
net/ipv4/ip_fragment.c | 12 ++++++++++++
net/ipv6/reassembly.c | 11 +++++++++++
3 files changed, 24 insertions(+)
Signed-off-by: David S. Miller <davem@davemloft.net>
Impact: Attribute function with __releases(...)
Fix this sparse warning:
net/ipv4/inet_fragment.c:276:35: warning: context imbalance in 'inet_frag_find' - unexpected unlock
Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
On Fri, 2008-03-28 at 03:24 -0700, Andrew Morton wrote:
> they should all be renamed.
Done for include/net and net
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
On namespace start we mainly prepare the ctl variables.
When the namespace is stopped we have to kill all the fragments that
point to this namespace. The inet_frags_exit_net() handles it.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The inet_frags.lru_list is used for evicting only, so we have
to make it per-namespace, to evict only those fragments, who's
namespace exceeded its high threshold, but not the whole hash.
Besides, this helps to avoid long loops in evictor.
The spinlock is not per-namespace because it protects the
hash table as well, which is global.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since we have one hashtable to lookup the fragment, having
different secret_interval-s for hash rebuild doesn't make
sense, so move this one to inet_frags.
The inet_frags_ctl becomes empty after this, so remove it.
The appropriate ctl table is kept read-only in namespaces.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is the same as with the timeout variable.
Currently, after exceeding the high threshold _all_
the fragments are evicted, but it will be fixed in
later patch.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move it to the netns_frags, adjust the usage and
make the appropriate ctl table writable.
Now fragment, that live in different namespaces can
live for different times.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is also simple, but introduces more changes, since
then mem counter is altered in more places.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
