netfilter: xtables: stackptr should be percpu
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>
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index c00cc0c..24e5d01 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -397,7 +397,7 @@
* @stacksize jumps (number of user chains) can possibly be made.
*/
unsigned int stacksize;
- unsigned int *stackptr;
+ unsigned int __percpu *stackptr;
void ***jumpstack;
/* ipt_entry tables: one per CPU */
/* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 63958f3..4b6c5ca 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -336,7 +336,7 @@
cpu = smp_processor_id();
table_base = private->entries[cpu];
jumpstack = (struct ipt_entry **)private->jumpstack[cpu];
- stackptr = &private->stackptr[cpu];
+ stackptr = per_cpu_ptr(private->stackptr, cpu);
origptr = *stackptr;
e = get_entry(table_base, private->hook_entry[hook]);
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 6f517bd..9d2d68f 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -363,7 +363,7 @@
cpu = smp_processor_id();
table_base = private->entries[cpu];
jumpstack = (struct ip6t_entry **)private->jumpstack[cpu];
- stackptr = &private->stackptr[cpu];
+ stackptr = per_cpu_ptr(private->stackptr, cpu);
origptr = *stackptr;
e = get_entry(table_base, private->hook_entry[hook]);
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 47b1e79..e34622f 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -699,10 +699,8 @@
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 @@
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)