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Commit 8dbde28d authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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[NET]: NET_CLS_ROUTE : convert ip_rt_acct to per_cpu variables 



ip_rt_acct needs 4096 bytes per cpu to perform some accounting.
It is actually allocated as a single huge array [4096*NR_CPUS]
(rounded up to a power of two)

Converting it to a per cpu variable is wanted to :
 - Save space on machines were num_possible_cpus() < NR_CPUS
 - Better NUMA placement (each cpu gets memory on its node)

Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 68f8353b

net/ipv4/ip_input.c

+1 −1
Original line number Diff line number Diff line
@@ -347,7 +347,7 @@ static int ip_rcv_finish(struct sk_buff *skb) 


#ifdef CONFIG_NET_CLS_ROUTE

	if (unlikely(skb->dst->tclassid)) {

		struct ip_rt_acct *st = ip_rt_acct + 256*smp_processor_id();

		struct ip_rt_acct *st = per_cpu_ptr(ip_rt_acct, smp_processor_id());

		u32 idx = skb->dst->tclassid;

		st[idx&0xFF].o_packets++;

		st[idx&0xFF].o_bytes+=skb->len;

net/ipv4/route.c

+3 −12
Original line number Diff line number Diff line
@@ -2858,12 +2858,10 @@ ctl_table ipv4_route_table[] = { 
#endif



#ifdef CONFIG_NET_CLS_ROUTE

struct ip_rt_acct *ip_rt_acct;



/* This code sucks.  But you should have seen it before! --RR */

struct ip_rt_acct *ip_rt_acct __read_mostly;



/* IP route accounting ptr for this logical cpu number. */

#define IP_RT_ACCT_CPU(i) (ip_rt_acct + i * 256)

#define IP_RT_ACCT_CPU(cpu) (per_cpu_ptr(ip_rt_acct, cpu))



#ifdef CONFIG_PROC_FS

static int ip_rt_acct_read(char *buffer, char **start, off_t offset,
@@ -2923,16 +2921,9 @@ int __init ip_rt_init(void) 
			     (jiffies ^ (jiffies >> 7)));



#ifdef CONFIG_NET_CLS_ROUTE

	{

	int order;

	for (order = 0;

	     (PAGE_SIZE << order) < 256 * sizeof(struct ip_rt_acct) * NR_CPUS; order++)

		/* NOTHING */;

	ip_rt_acct = (struct ip_rt_acct *)__get_free_pages(GFP_KERNEL, order);

	ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct));

	if (!ip_rt_acct)

		panic("IP: failed to allocate ip_rt_acct\n");

	memset(ip_rt_acct, 0, PAGE_SIZE << order);

	}

#endif



	ipv4_dst_ops.kmem_cachep =