[PATCH v3 17/30] inet: frags: reorganize struct netns_frags

Stephen Hemminger
2018-09-13T20:09:25Z

From: Eric Dumazet <edumazet@google.com>

Put the read-mostly fields in a separate cache line
at the beginning of struct netns_frags, to reduce
false sharing noticed in inet_frag_kill()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit c2615cf5a761b32bf74e85bddc223dfff3d9b9f0)
---
include/net/inet_frag.h | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index a52e7273e7a5..ed07e3786d98 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -5,16 +5,17 @@
#include <linux/rhashtable.h>

struct netns_frags {
- struct rhashtable rhashtable ____cacheline_aligned_in_smp;
-
- /* Keep atomic mem on separate cachelines in structs that include it */
- atomic_long_t mem ____cacheline_aligned_in_smp;
/* sysctls */
long high_thresh;
long low_thresh;
int timeout;
int max_dist;
struct inet_frags *f;
+
+ struct rhashtable rhashtable ____cacheline_aligned_in_smp;
+
+ /* Keep atomic mem on separate cachelines in structs that include it */
+ atomic_long_t mem ____cacheline_aligned_in_smp;
};

/**
--
2.18.0