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

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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: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Pavel Emelyanov 2008-03-28 16:38:43 -07:00 committed by David S. Miller
parent 13ff3d6fa4
commit 1338d466d9
2 changed files with 27 additions and 8 deletions
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13
include/net/sock.h
View File

@ -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);

22
net/core/sock.c
View File

@ -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)
{