netdev - [PATCH] neigh: reorder struct neighbour

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 11 Nov 2010 17:57:19 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev <netdev@...r.kernel.org>
Subject: [PATCH] neigh: reorder struct neighbour

It is important to move nud_state outside of the often modified cache
line (because of refcnt), to reduce false sharing in neigh_event_send()

This is a followup of commit 0ed8ddf4045f (neigh: Protect neigh->ha[]
with a seqlock)

This gives a 7% speedup on routing test with IP route cache disabled.

Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
---
David, it appears I forgot to push this patch, I have it in my tree
since one month. Thanks !

 include/net/neighbour.h |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 55590ab..815b2ce 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -96,16 +96,16 @@ struct neighbour {
 	struct neigh_parms	*parms;
 	unsigned long		confirmed;
 	unsigned long		updated;
-	__u8			flags;
-	__u8			nud_state;
-	__u8			type;
-	__u8			dead;
+	rwlock_t		lock;
 	atomic_t		refcnt;
 	struct sk_buff_head	arp_queue;
 	struct timer_list	timer;
 	unsigned long		used;
 	atomic_t		probes;
-	rwlock_t		lock;
+	__u8			flags;
+	__u8			nud_state;
+	__u8			type;
+	__u8			dead;
 	seqlock_t		ha_lock;
 	unsigned char		ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
 	struct hh_cache		*hh;


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html