Commit 5f58a5c8 authored Feb 07, 2008 by Eric Dumazet Committed by David S. Miller Feb 07, 2008

[IPSEC] flow: Remove an unnecessary ____cacheline_aligned



We use a percpu variable named flow_hash_info, which holds 12 bytes.

It is currently marked as ____cacheline_aligned, which makes linker
skip space to properly align this variable.

Before :
c065cc90 D per_cpu__softnet_data
c065cd00 d per_cpu__flow_tables
<Here, hole of 124 bytes>
c065cd80 d per_cpu__flow_hash_info
<Here, hole of 116 bytes>
c065ce00 d per_cpu__flow_flush_tasklets
c065ce14 d per_cpu__rt_cache_stat


This alignement is quite unproductive, and removing it reduces the
size of percpu data (by 240 bytes on my x86 machine), and improves
performance (flow_tables & flow_hash_info can share a single cache
line)

After patch :
c065cc04 D per_cpu__softnet_data
c065cc4c d per_cpu__flow_tables
c065cc50 d per_cpu__flow_hash_info
c065cc5c d per_cpu__flow_flush_tasklets
c065cc70 d per_cpu__rt_cache_stat

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 4136cd52

net/core/flow.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -52,7 +52,7 @@ struct flow_percpu_info {
		int hash_rnd_recalc;
		u32 hash_rnd;
		int count;
		} ____cacheline_aligned;
		};
		static DEFINE_PER_CPU(struct flow_percpu_info, flow_hash_info) = { 0 };

		#define flow_hash_rnd_recalc(cpu) \

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