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Stephen Hemminger authored
The x_tables are organized with a table structure and a per-cpu copies of the counters and rules. On older kernels there was a reader/writer lock per table which was a performance bottleneck. In 2.6.30-rc, this was converted to use RCU and the counters/rules which solved the performance problems for do_table but made replacing rules much slower because of the necessary RCU grace period. This version uses a per-cpu set of spinlocks and counters to allow to table processing to proceed without the cache thrashing of a global reader lock and keeps the same performance for table updates. Signed-off-by:
Stephen Hemminger <shemminger@vyatta.com> Acked-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
David S. Miller <davem@davemloft.net>
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