linux.git/include/net/dst.h, branch v2.6.29

netns xfrm: lookup in netns

2008-11-26T01:35:18+00:00

Pass netns to xfrm_lookup()/__xfrm_lookup(). For that pass netns
to flow_cache_lookup() and resolver callback.

Take it from socket or netdevice. Stub DECnet to init_net.

Signed-off-by: Alexey Dobriyan 
Signed-off-by: David S. Miller

net: make sure struct dst_entry refcount is aligned on 64 bytes

2008-11-17T03:46:36+00:00

As found in the past (commit f1dd9c379cac7d5a76259e7dffcd5f8edc697d17
[NET]: Fix tbench regression in 2.6.25-rc1), it is really
important that struct dst_entry refcount is aligned on a cache line.

We cannot use __atribute((aligned)), so manually pad the structure
for 32 and 64 bit arches.

for 32bit : offsetof(truct dst_entry, __refcnt) is 0x80
for 64bit : offsetof(truct dst_entry, __refcnt) is 0xc0

As it is not possible to guess at compile time cache line size,
we use a generic value of 64 bytes, that satisfies many current arches.
(Using 128 bytes alignment on 64bit arches would waste 64 bytes)

Add a BUILD_BUG_ON to catch future updates to "struct dst_entry" dont
break this alignment.

"tbench 8" is 4.4 % faster on a dual quad core (HP BL460c G1), Intel E5450 @3.00GHz
(2350 MB/s instead of 2250 MB/s)

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: remove struct dst_entry::entry_size

2008-11-12T01:25:22+00:00

Unused after kmem_cache_zalloc() conversion.

Signed-off-by: Alexey Dobriyan 
Signed-off-by: David S. Miller

net: reduce structures when XFRM=n

2008-10-28T20:24:06+00:00

ifdef out
* struct sk_buff::sp		(pointer)
* struct dst_entry::xfrm	(pointer)
* struct sock::sk_policy	(2 pointers)

Signed-off-by: Alexey Dobriyan 
Signed-off-by: David S. Miller

net: Kill plain NET_XMIT_BYPASS.

2008-08-05T06:04:08+00:00

dst_input() was doing something completely absurd, looping
on skb->dst->input() if NET_XMIT_BYPASS was seen, but these
functions never return such an error.

And as a result plain ole' NET_XMIT_BYPASS has no more
references and can be completely killed off.

Signed-off-by: David S. Miller

tcp: RTT metrics scaling

2008-07-19T06:02:15+00:00

Some of the metrics (RTT, RTTVAR and RTAX_RTO_MIN) are stored in
kernel units (jiffies) and this leaks out through the netlink API to
user space where the units for jiffies are unknown.

This patches changes the kernel to convert to/from milliseconds. This
changes the ABI, but milliseconds seemed like the most natural unit
for these parameters.  Values available via syscall in
/proc/net/rt_cache and netlink will be in milliseconds.

Signed-off-by: Stephen Hemminger 
Signed-off-by: David S. Miller

[NET]: uninline dst_release

2008-03-28T00:53:31+00:00

Codiff stats (allyesconfig, v2.6.24-mm1):
-16420  187 funcs, 103 +, 16523 -, diff: -16420 --- dst_release

Without number of debug related CONFIGs (v2.6.25-rc2-mm1):
-7257  186 funcs, 70 +, 7327 -, diff: -7257 --- dst_release
dst_release                   |  +40

Signed-off-by: Ilpo Järvinen 
Signed-off-by: David S. Miller

[NET]: Fix tbench regression in 2.6.25-rc1

2008-03-13T05:52:37+00:00

Comparing with kernel 2.6.24, tbench result has regression with
2.6.25-rc1.

1) On 2 quad-core processor stoakley: 4%.
2) On 4 quad-core processor tigerton: more than 30%.

bisect located below patch.

b4ce92775c2e7ff9cf79cca4e0a19c8c5fd6287b is first bad commit
commit b4ce92775c2e7ff9cf79cca4e0a19c8c5fd6287b
Author: Herbert Xu 
Date:   Tue Nov 13 21:33:32 2007 -0800

    [IPV6]: Move nfheader_len into rt6_info

    The dst member nfheader_len is only used by IPv6.  It's also currently
    creating a rather ugly alignment hole in struct dst.  Therefore this patch
    moves it from there into struct rt6_info.

Above patch changes the cache line alignment, especially member
__refcnt. I did a testing by adding 2 unsigned long pading before
lastuse, so the 3 members, lastuse/__refcnt/__use, are moved to next
cache line. The performance is recovered.

I created a patch to rearrange the members in struct dst_entry.

With Eric and Valdis Kletnieks's suggestion, I made finer arrangement.

1) Move tclassid under ops in case CONFIG_NET_CLS_ROUTE=y. So
   sizeof(dst_entry)=200 no matter if CONFIG_NET_CLS_ROUTE=y/n. I
   tested many patches on my 16-core tigerton by moving tclassid to
   different place. It looks like tclassid could also have impact on
   performance.  If moving tclassid before metrics, or just don't move
   tclassid, the performance isn't good. So I move it behind metrics.

2) Add comments before __refcnt.

On 16-core tigerton:

If CONFIG_NET_CLS_ROUTE=y, the result with below patch is about 18%
better than the one without the patch;

If CONFIG_NET_CLS_ROUTE=n, the result with below patch is about 30%
better than the one without the patch.

With 32bit 2.6.25-rc1 on 8-core stoakley, the new patch doesn't
introduce regression.

Thank Eric, Valdis, and David!

Signed-off-by: Zhang Yanmin 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

[DST]: shrinks sizeof(struct rtable) by 64 bytes on x86_64

2008-01-28T23:10:41+00:00

On x86_64, sizeof(struct rtable) is 0x148, which is rounded up to
0x180 bytes by SLAB allocator.

We can reduce this to exactly 0x140 bytes, without alignment overhead,
and store 12 struct rtable per PAGE instead of 10.

rate_tokens is currently defined as an "unsigned long", while its
content should not exceed 6*HZ. It can safely be converted to an
unsigned int.

Moving tclassid right after rate_tokens to fill the 4 bytes hole
permits to save 8 bytes on 'struct dst_entry', which finally permits
to save 8 bytes on 'struct rtable'

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

[NETNS][DST]: Add the network namespace pointer in dst_ops

2008-01-28T23:02:47+00:00

The network namespace pointer can be stored into the dst_ops structure.
This is usefull when there are multiple instances of the dst_ops for a
protocol. When there are no several instances, this field will be never
used in the protocol. So there is no impact for the protocols which do
implement the network namespaces.

Signed-off-by: Daniel Lezcano 
Signed-off-by: David S. Miller