Commit 1338d466 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by David S. Miller
Browse files

[SOCK]: Introduce a percpu inuse counters array (v2). 



And redirect sock_prot_inuse_add and _get to use one.

As far as the dereferences are concerned. Before the patch we made
1 dereference to proto->inuse.add call, the call itself and then
called the __get_cpu_var() on a static variable. After the patch we 
make a direct call, then one dereference to proto->inuse_idx and 
then the same __get_cpu_var() on a still static variable. So this 
patch doesn't seem to produce performance penalty on SMP.

This is not per-net yet, but I will deliberately make NET_NS=y case
separated from NET_NS=n one, since it'll cost us one-or-two more 
dereferences to get the struct net and the inuse counter.

Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Acked-by: default avatarEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 13ff3d6f

include/net/sock.h

+5 −8
Original line number Diff line number Diff line
@@ -639,18 +639,15 @@ static inline void sk_refcnt_debug_release(const struct sock *sk) 
# define DEFINE_PROTO_INUSE(NAME) DEFINE_PCOUNTER(NAME)

# define REF_PROTO_INUSE(NAME) PCOUNTER_MEMBER_INITIALIZER(NAME, .inuse)

/* Called with local bh disabled */

static inline void sock_prot_inuse_add(struct proto *prot, int inc)

{

	pcounter_add(&prot->inuse, inc);

}

extern void sock_prot_inuse_add(struct proto *prot, int inc);



static inline int sock_prot_inuse_init(struct proto *proto)

{

	return pcounter_alloc(&proto->inuse);

}

static inline int sock_prot_inuse_get(struct proto *proto)

{

	return pcounter_getval(&proto->inuse);

}



extern int sock_prot_inuse_get(struct proto *proto);



static inline void sock_prot_inuse_free(struct proto *proto)

{

	pcounter_free(&proto->inuse);

net/core/sock.c

+22 −0
Original line number Diff line number Diff line
@@ -1942,8 +1942,30 @@ static LIST_HEAD(proto_list); 


#ifdef CONFIG_PROC_FS

#define PROTO_INUSE_NR	64	/* should be enough for the first time */

struct prot_inuse {

	int val[PROTO_INUSE_NR];

};



static DECLARE_BITMAP(proto_inuse_idx, PROTO_INUSE_NR);

static DEFINE_PER_CPU(struct prot_inuse, prot_inuse);



void sock_prot_inuse_add(struct proto *prot, int val)

{

	__get_cpu_var(prot_inuse).val[prot->inuse_idx] += val;

}

EXPORT_SYMBOL_GPL(sock_prot_inuse_add);



int sock_prot_inuse_get(struct proto *prot)

{

	int cpu, idx = prot->inuse_idx;

	int res = 0;



	for_each_possible_cpu(cpu)

		res += per_cpu(prot_inuse, cpu).val[idx];



	return res >= 0 ? res : 0;

}

EXPORT_SYMBOL_GPL(sock_prot_inuse_get);



static void assign_proto_idx(struct proto *prot)

{

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