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* [PATCH next] netfilter: nf_queue: place volatile data in own cacheline
@ 2016-10-30 23:35 Florian Westphal
  2016-10-31 14:19 ` Pablo Neira Ayuso
  0 siblings, 1 reply; 2+ messages in thread
From: Florian Westphal @ 2016-10-30 23:35 UTC (permalink / raw)
  To: netfilter-devel; +Cc: Florian Westphal

As the comment indicates, the data at the end of nfqnl_instance struct is
written on every queue/dequeue, so it should reside in its own cacheline.

Before this change, 'lock' was in first cacheline so we dirtied both.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nfnetlink_queue.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index af832c526048..5379f788a372 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -69,7 +69,7 @@ struct nfqnl_instance {
  * Following fields are dirtied for each queued packet,
  * keep them in same cache line if possible.
  */
-	spinlock_t	lock;
+	spinlock_t	lock	____cacheline_aligned_in_smp;
 	unsigned int	queue_total;
 	unsigned int	id_sequence;		/* 'sequence' of pkt ids */
 	struct list_head queue_list;		/* packets in queue */
-- 
2.7.3


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH next] netfilter: nf_queue: place volatile data in own cacheline
  2016-10-30 23:35 [PATCH next] netfilter: nf_queue: place volatile data in own cacheline Florian Westphal
@ 2016-10-31 14:19 ` Pablo Neira Ayuso
  0 siblings, 0 replies; 2+ messages in thread
From: Pablo Neira Ayuso @ 2016-10-31 14:19 UTC (permalink / raw)
  To: Florian Westphal; +Cc: netfilter-devel

On Mon, Oct 31, 2016 at 12:35:07AM +0100, Florian Westphal wrote:
> As the comment indicates, the data at the end of nfqnl_instance struct is
> written on every queue/dequeue, so it should reside in its own cacheline.
> 
> Before this change, 'lock' was in first cacheline so we dirtied both.

Applied, thanks Florian.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2016-10-30 23:35 [PATCH next] netfilter: nf_queue: place volatile data in own cacheline Florian Westphal
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