|author||Eric Dumazet <email@example.com>||2007-11-05 23:38:39 -0800|
|committer||David S. Miller <firstname.lastname@example.org>||2007-11-07 04:08:57 -0800|
|parent||[PPP]: L2TP: Fix oops in transmit and receive paths (diff)|
[NET]: Define infrastructure to keep 'inuse' changes in an efficent SMP/NUMA way.
"struct proto" currently uses an array stats[NR_CPUS] to track change on 'inuse' sockets per protocol. If NR_CPUS is big, this means we use a big memory area for this. Moreover, all this memory area is located on a single node on NUMA machines, increasing memory pressure on the boot node. In this patch, I tried to : - Keep a fast !CONFIG_SMP implementation - Keep a fast CONFIG_SMP implementation for often used protocols (tcp,udp,raw,...) - Introduce a NUMA efficient implementation Some helper macros are defined in include/net/sock.h These macros take into account CONFIG_SMP If a "struct proto" is declared without using DEFINE_PROTO_INUSE / REF_PROTO_INUSE macros, it will automatically use a default implementation, using a dynamically allocated percpu zone. This default implementation will be NUMA efficient, but might use 32/64 bytes per possible cpu because of current alloc_percpu() implementation. However it still should be better than previous implementation based on stats[NR_CPUS] field. When a "struct proto" is changed to use the new macros, we use a single static "int" percpu variable, lowering the memory and cpu costs, still preserving NUMA efficiency. Signed-off-by: Eric Dumazet <email@example.com> Signed-off-by: David S. Miller <firstname.lastname@example.org>
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