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netfilter: xtables: stackptr should be percpu

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commit f3c5c1bfd4 (netfilter: xtables: make ip_tables reentrant)
introduced a performance regression, because stackptr array is shared by
all cpus, adding cache line ping pongs. (16 cpus share a 64 bytes cache
line)

Fix this using alloc_percpu()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-By: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Eric Dumazet
2010-05-31 16:41:35 +02:00
committed by Patrick McHardy
parent c936e8bd1d
commit 7489aec8ee
4 changed files with 6 additions and 13 deletions
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net/netfilter/x_tables.c
+3 -10
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@@ -699,10 +699,8 @@ void xt_free_table_info(struct xt_table_info *info)
vfree(info->jumpstack);
else
kfree(info->jumpstack);
if (sizeof(unsigned int) * nr_cpu_ids > PAGE_SIZE)
vfree(info->stackptr);
else
kfree(info->stackptr);
free_percpu(info->stackptr);
kfree(info);
}
@@ -753,14 +751,9 @@ static int xt_jumpstack_alloc(struct xt_table_info *i)
unsigned int size;
int cpu;
size = sizeof(unsigned int) * nr_cpu_ids;
if (size > PAGE_SIZE)
i->stackptr = vmalloc(size);
else
i->stackptr = kmalloc(size, GFP_KERNEL);
i->stackptr = alloc_percpu(unsigned int);
if (i->stackptr == NULL)
return -ENOMEM;
memset(i->stackptr, 0, size);
size = sizeof(void **) * nr_cpu_ids;
if (size > PAGE_SIZE)