Subject: [RFC net-next PATCH V1 8/9] net: increase frag queue hash size and cache-line

From: Jesper Dangaard Brouer <[email-masked]>
Date: Fri, 23 Nov 2012 14:08:42 +0100

Increase frag queue hash size and assure cache-line alignment to
avoid false sharing.  Hash size is set to 256, because I have
observed 206 frag queues in use at 4x10G with packet size 4416 bytes.

Signed-off-by: Jesper Dangaard Brouer <[email-masked]>
---

 include/net/inet_frag.h |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 1efec6b..5054228 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -49,13 +49,12 @@ struct inet_frag_queue {
 	u16			max_size;
 };
 
-#define INETFRAGS_HASHSZ		64
-
+#define INETFRAGS_HASHSZ	256
 
 struct inet_frag_bucket {
 	struct hlist_head	chain;
 	spinlock_t		chain_lock;
-};
+} ____cacheline_aligned_in_smp;
 
 struct inet_frags {
 	struct inet_frag_bucket	hash[INETFRAGS_HASHSZ];