From 6180d9de61a5c461f9e3efef5417a844701dbbb2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 18 Nov 2015 06:31:01 -0800 Subject: [PATCH] net: move napi_hash[] into read mostly section We do not often add/delete a napi context. Moving napi_hash[] into read mostly section avoids potential false sharing. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/hashtable.h | 4 ++++ net/core/dev.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/include/linux/hashtable.h b/include/linux/hashtable.h index 519b6e2d769e..661e5c2a8e2a 100644 --- a/include/linux/hashtable.h +++ b/include/linux/hashtable.h @@ -16,6 +16,10 @@ struct hlist_head name[1 << (bits)] = \ { [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT } +#define DEFINE_READ_MOSTLY_HASHTABLE(name, bits) \ + struct hlist_head name[1 << (bits)] __read_mostly = \ + { [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT } + #define DECLARE_HASHTABLE(name, bits) \ struct hlist_head name[1 << (bits)] diff --git a/net/core/dev.c b/net/core/dev.c index ff58a8bc5e3c..02dfbd91a8e4 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -184,7 +184,7 @@ EXPORT_SYMBOL(dev_base_lock); static DEFINE_SPINLOCK(napi_hash_lock); static unsigned int napi_gen_id = NR_CPUS; -static DEFINE_HASHTABLE(napi_hash, 8); +static DEFINE_READ_MOSTLY_HASHTABLE(napi_hash, 8); static seqcount_t devnet_rename_seq;