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Commit 7489aec8 authored by Eric Dumazet's avatar Eric Dumazet Committed by Patrick McHardy
Browse files

netfilter: xtables: stackptr should be percpu 



commit f3c5c1bf (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: default avatarEric Dumazet <eric.dumazet@gmail.com>
Acked-By: default avatarJan Engelhardt <jengelh@medozas.de>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
parent c936e8bd

include/linux/netfilter/x_tables.h

+1 −1
Original line number Diff line number Diff line
@@ -397,7 +397,7 @@ struct xt_table_info { 
	 * @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 */

net/ipv4/netfilter/ip_tables.c

+1 −1
Original line number Diff line number Diff line
@@ -336,7 +336,7 @@ ipt_do_table(struct sk_buff *skb, 
	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]);

net/ipv6/netfilter/ip6_tables.c

+1 −1
Original line number Diff line number Diff line
@@ -363,7 +363,7 @@ ip6t_do_table(struct sk_buff *skb, 
	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]);

net/netfilter/x_tables.c

+3 −10
Original line number Diff line number Diff line
@@ -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)