[PATCH net-2.6.26 2/5][SOCK]: Introduce a percpu inuse counting array.
From: Pavel Emelyanov <hidden>
Date: 2008-03-28 09:03:11
Subsystem:
networking [general], networking [sockets], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Willem de Bruijn, Linus Torvalds
And redirect sock_prot_inuse_add|_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 made a __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. Besides, add a sanity check into inuse_idx generator. This is net per-net yet, but I will deliberately make this case separated from NET_NS=n, since it'll cost us one-or-two more dereferences to get the struct net and the inuse counter. Signed-off-by: Pavel Emelyanov <redacted> --- include/net/sock.h | 13 +++++-------- net/core/sock.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+), 8 deletions(-)
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 @@ 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);
diff --git a/net/core/sock.c b/net/core/sock.c
index a7faf30..2b6f8f1 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c@@ -1940,11 +1940,45 @@ EXPORT_SYMBOL(sk_common_release); static DEFINE_RWLOCK(proto_list_lock); 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 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); +#endif + static void assign_proto_idx(struct proto *prot) { #ifdef CONFIG_PROC_FS static unsigned int idx = 0; + if (unlikely(idx == PROTO_INUSE_NR - 1)) { + printk(KERN_ERR "PROTO_INUSE_NR exhausted\n"); + prot->inuse_idx = idx; + return; + } + prot->inuse_idx = idx++; #endif }
--
1.5.3.4