Commit a1a56aaa authored by Eric Dumazet's avatar Eric Dumazet Committed by Pablo Neira Ayuso

netfilter: x_tables: align per cpu xt_counter

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: default avatarEric Dumazet <edumazet@google.com>
Cc: Florian Westphal <fw@strlen.de>
Acked-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 01555e74
......@@ -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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