netdev - [IPV4] FIB_HASH: Reduce memory needs and speedup lookups

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 16 Jan 2008 07:58:24 +0100
From:	Eric Dumazet <dada1@...mosbay.com>
To:	"David S. Miller" <davem@...emloft.net>
CC:	Linux Netdev List <netdev@...r.kernel.org>
Subject: [IPV4] FIB_HASH: Reduce memory needs and speedup lookups

Hi David

CONFIG_FIB_HASH=y being default configuration, we can still work on it.

Thank you

[IPV4] FIB_HASH: Reduce memory needs and speedup lookups

Currently, sizeof(struct fib_alias) is 24 or 48 bytes on 32/64 bits arches.

Because of SLAB_HWCACHE_ALIGN requirement, these are rounded to 32 and 64 
bytes respectively.

This patch moves rcu to the end of fib_alias, and conditionally defines it 
only for CONFIG_IP_FIB_TRIE.

We also remove SLAB_HWCACHE_ALIGN requirement for fib_alias and fib_node 
objects because it is not necessary.

(BTW SLUB currently denies it for objects smaller than cache_line_size() / 2,
but not SLAB)

Finally, sizeof(fib_alias) go back to 16 and 32 bytes.

Then, we can embed one fib_alias on each fib_node, to favor locality.
Most of the time access to the fib_alias will be free because one cache line
contains both the list head (fn_alias) and (one of) the list element.

Signed-off-by: Eric Dumazet <dada1@...mosbay.com>

  net/ipv4/fib_hash.c   |   33 ++++++++++++++++++++-------------
  net/ipv4/fib_lookup.h |    4 +++-
  2 files changed, 23 insertions(+), 14 deletions(-)

View attachment "fib_hash.patch" of type "text/plain" (3290 bytes)