Re: [PATCH net-next] x_table: align per cpu xt_counter
On Wed, Jun 17, 2015 at 07:08:15PM +0200, Florian Westphal wrote: > Eric Dumazet wrote: > > From: Eric Dumazet > > > > Let's force a 16 bytes alignment on xt_counter percpu allocations, > > so that bytes and packets sit in same cache line. > > > > xt_counter being exported to user space, we cannot add __align(16) on > > the structure itself. > > Sorry, I was away. Looks great. > > Acked-by: Florian Westphal Applied, thanks Eric and Florian ! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH net-next] x_table: align per cpu xt_counter
On Thu, Jun 18, 2015 at 03:43:26AM -0700, David Miller wrote: > From: Eric Dumazet > Date: Mon, 15 Jun 2015 18:10:13 -0700 > > > From: Eric Dumazet > > > > Let's force a 16 bytes alignment on xt_counter percpu allocations, > > so that bytes and packets sit in same cache line. > > > > xt_counter being exported to user space, we cannot add __align(16) on > > the structure itself. > > > > Signed-off-by: Eric Dumazet > > Cc: Florian Westphal > > Pablo, I assume you will take this. Yes, I'll prepare another pull request for you along today. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH net-next] x_table: align per cpu xt_counter
From: Eric Dumazet Date: Mon, 15 Jun 2015 18:10:13 -0700 > From: Eric Dumazet > > Let's force a 16 bytes alignment on xt_counter percpu allocations, > so that bytes and packets sit in same cache line. > > xt_counter being exported to user space, we cannot add __align(16) on > the structure itself. > > Signed-off-by: Eric Dumazet > Cc: Florian Westphal Pablo, I assume you will take this. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH net-next] x_table: align per cpu xt_counter
Eric Dumazet wrote: > From: Eric Dumazet > > Let's force a 16 bytes alignment on xt_counter percpu allocations, > so that bytes and packets sit in same cache line. > > xt_counter being exported to user space, we cannot add __align(16) on > the structure itself. Sorry, I was away. Looks great. Acked-by: Florian Westphal -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH net-next] x_table: align per cpu xt_counter
From: Eric Dumazet
Let's force a 16 bytes alignment on xt_counter percpu allocations,
so that bytes and packets sit in same cache line.
xt_counter being exported to user space, we cannot add __align(16) on
the structure itself.
Signed-off-by: Eric Dumazet
Cc: Florian Westphal
---
include/linux/netfilter/x_tables.h |6 --
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/netfilter/x_tables.h
b/include/linux/netfilter/x_tables.h
index
95693c4cebdda473a2f3e427dcc2511e83bf7405..1c97a2204379e14676ee33f0b15c5174b7afe680
100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -356,7 +356,8 @@ static inline unsigned long ifname_compare_aligned(const
char *_a,
* so nothing needs to be done there.
*
* xt_percpu_counter_alloc returns the address of the percpu
- * counter, or 0 on !SMP.
+ * counter, or 0 on !SMP. We force an alignment of 16 bytes
+ * so that bytes/packets share a common cache line.
*
* Hence caller must use IS_ERR_VALUE to check for error, this
* allows us to return 0 for single core systems without forcing
@@ -365,7 +366,8 @@ static inline unsigned long ifname_compare_aligned(const
char *_a,
static inline u64 xt_percpu_counter_alloc(void)
{
if (nr_cpu_ids > 1) {
- void __percpu *res = alloc_percpu(struct xt_counters);
+ void __percpu *res = __alloc_percpu(sizeof(struct xt_counters),
+ sizeof(struct xt_counters));
if (res == NULL)
return (u64) -ENOMEM;
--
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