[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: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index abc6341..ebf9552 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -639,18 +639,15 @@
# 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);
diff --git a/net/core/sock.c b/net/core/sock.c
index 7d2c8add..174c64b 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1942,8 +1942,30 @@
#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)
{
