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[NET]: Define infrastructure to keep 'inuse' changes in an efficent SMP/NUMA way. 

"struct proto" currently uses an array stats[NR_CPUS] to track change on
'inuse' sockets per protocol.

If NR_CPUS is big, this means we use a big memory area for this.
Moreover, all this memory area is located on a single node on NUMA
machines, increasing memory pressure on the boot node.

In this patch, I tried to :

- Keep a fast !CONFIG_SMP implementation
- Keep a fast CONFIG_SMP implementation for often used protocols
(tcp,udp,raw,...)
- Introduce a NUMA efficient implementation

Some helper macros are defined in include/net/sock.h
These macros take into account CONFIG_SMP

If a "struct proto" is declared without using DEFINE_PROTO_INUSE /
REF_PROTO_INUSE
macros, it will automatically use a default implementation, using a
dynamically allocated percpu zone.
This default implementation will be NUMA efficient, but might use 32/64
bytes per possible cpu
because of current alloc_percpu() implementation.
However it still should be better than previous implementation based on
stats[NR_CPUS] field.

When a "struct proto" is changed to use the new macros, we use a single
static "int" percpu variable,
lowering the memory and cpu costs, still preserving NUMA efficiency.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2007-11-05 23:38:39 -08:00 committed by David S. Miller
parent 91781004b9
commit 286ab3d460
4 changed files with 112 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

63
include/net/sock.h
View File

@ -560,6 +560,14 @@ struct proto {
void (*unhash)(struct sock *sk);
int (*get_port)(struct sock *sk, unsigned short snum);
#ifdef CONFIG_SMP
/* Keeping track of sockets in use */
void (*inuse_add)(struct proto *prot, int inc);
int (*inuse_getval)(const struct proto *prot);
int *inuse_ptr;
#else
int inuse;
#endif
/* Memory pressure */
void (*enter_memory_pressure)(void);
atomic_t *memory_allocated; /* Current allocated memory. */
@ -592,12 +600,38 @@ struct proto {
#ifdef SOCK_REFCNT_DEBUG
atomic_t socks;
#endif
struct {
int inuse;
u8 __pad[SMP_CACHE_BYTES - sizeof(int)];
} stats[NR_CPUS];
};
/*
* Special macros to let protos use a fast version of inuse{get|add}
* using a static percpu variable per proto instead of an allocated one,
* saving one dereference.
* This might be changed if/when dynamic percpu vars become fast.
*/
#ifdef CONFIG_SMP
# define DEFINE_PROTO_INUSE(NAME) \
static DEFINE_PER_CPU(int, NAME##_inuse); \
static void NAME##_inuse_add(struct proto *prot, int inc) \
{ \
__get_cpu_var(NAME##_inuse) += inc; \
} \
\
static int NAME##_inuse_getval(const struct proto *prot)\
{ \
int res = 0, cpu; \
\
for_each_possible_cpu(cpu) \
res += per_cpu(NAME##_inuse, cpu); \
return res; \
}
# define REF_PROTO_INUSE(NAME) \
.inuse_add = NAME##_inuse_add, \
.inuse_getval = NAME##_inuse_getval,
#else
# define DEFINE_PROTO_INUSE(NAME)
# define REF_PROTO_INUSE(NAME)
#endif
extern int proto_register(struct proto *prot, int alloc_slab);
extern void proto_unregister(struct proto *prot);
@ -629,12 +663,29 @@ static inline void sk_refcnt_debug_release(const struct sock *sk)
/* Called with local bh disabled */
static __inline__ void sock_prot_inc_use(struct proto *prot)
{
prot->stats[smp_processor_id()].inuse++;
#ifdef CONFIG_SMP
prot->inuse_add(prot, 1);
#else
prot->inuse++;
#endif
}
static __inline__ void sock_prot_dec_use(struct proto *prot)
{
prot->stats[smp_processor_id()].inuse--;
#ifdef CONFIG_SMP
prot->inuse_add(prot, -1);
#else
prot->inuse--;
#endif
}
static __inline__ int sock_prot_inuse(struct proto *proto)
{
#ifdef CONFIG_SMP
return proto->inuse_getval(proto);
#else
return proto->inuse;
#endif
}
/* With per-bucket locks this operation is not-atomic, so that

48
net/core/sock.c
View File

@ -1801,12 +1801,41 @@ EXPORT_SYMBOL(sk_common_release);
static DEFINE_RWLOCK(proto_list_lock);
static LIST_HEAD(proto_list);
#ifdef CONFIG_SMP
/*
* Define default functions to keep track of inuse sockets per protocol
* Note that often used protocols use dedicated functions to get a speed increase.
* (see DEFINE_PROTO_INUSE/REF_PROTO_INUSE)
*/
static void inuse_add(struct proto *prot, int inc)
{
per_cpu_ptr(prot->inuse_ptr, smp_processor_id())[0] += inc;
}
static int inuse_get(const struct proto *prot)
{
int res = 0, cpu;
for_each_possible_cpu(cpu)
res += per_cpu_ptr(prot->inuse_ptr, cpu)[0];
return res;
}
#endif
int proto_register(struct proto *prot, int alloc_slab)
{
char *request_sock_slab_name = NULL;
char *timewait_sock_slab_name;
int rc = -ENOBUFS;
#ifdef CONFIG_SMP
if (!prot->inuse_getval || !prot->inuse_add) {
prot->inuse_ptr = alloc_percpu(int);
if (prot->inuse_ptr == NULL)
goto out;
prot->inuse_getval = inuse_get;
prot->inuse_add = inuse_add;
}
#endif
if (alloc_slab) {
prot->slab = kmem_cache_create(prot->name, prot->obj_size, 0,
SLAB_HWCACHE_ALIGN, NULL);
@ -1814,7 +1843,7 @@ int proto_register(struct proto *prot, int alloc_slab)
if (prot->slab == NULL) {
printk(KERN_CRIT "%s: Can't create sock SLAB cache!\n",
prot->name);
goto out;
goto out_free_inuse;
}
if (prot->rsk_prot != NULL) {
@ -1873,6 +1902,15 @@ out_free_request_sock_slab_name:
out_free_sock_slab:
kmem_cache_destroy(prot->slab);
prot->slab = NULL;
out_free_inuse:
#ifdef CONFIG_SMP
if (prot->inuse_ptr != NULL) {
free_percpu(prot->inuse_ptr);
prot->inuse_ptr = NULL;
prot->inuse_getval = NULL;
prot->inuse_add = NULL;
}
#endif
goto out;
}
@ -1884,6 +1922,14 @@ void proto_unregister(struct proto *prot)
list_del(&prot->node);
write_unlock(&proto_list_lock);
#ifdef CONFIG_SMP
if (prot->inuse_ptr != NULL) {
free_percpu(prot->inuse_ptr);
prot->inuse_ptr = NULL;
prot->inuse_getval = NULL;
prot->inuse_add = NULL;
}
#endif
if (prot->slab != NULL) {
kmem_cache_destroy(prot->slab);
prot->slab = NULL;

19
net/ipv4/proc.c
View File

@ -46,17 +46,6 @@
#include <net/sock.h>
#include <net/raw.h>
static int fold_prot_inuse(struct proto *proto)
{
int res = 0;
int cpu;
for_each_possible_cpu(cpu)
res += proto->stats[cpu].inuse;
return res;
}
/*
* Report socket allocation statistics [mea@utu.fi]
*/
@ -64,12 +53,12 @@ static int sockstat_seq_show(struct seq_file *seq, void *v)
{
socket_seq_show(seq);
seq_printf(seq, "TCP: inuse %d orphan %d tw %d alloc %d mem %d\n",
fold_prot_inuse(&tcp_prot), atomic_read(&tcp_orphan_count),
sock_prot_inuse(&tcp_prot), atomic_read(&tcp_orphan_count),
tcp_death_row.tw_count, atomic_read(&tcp_sockets_allocated),
atomic_read(&tcp_memory_allocated));
seq_printf(seq, "UDP: inuse %d\n", fold_prot_inuse(&udp_prot));
seq_printf(seq, "UDPLITE: inuse %d\n", fold_prot_inuse(&udplite_prot));
seq_printf(seq, "RAW: inuse %d\n", fold_prot_inuse(&raw_prot));
seq_printf(seq, "UDP: inuse %d\n", sock_prot_inuse(&udp_prot));
seq_printf(seq, "UDPLITE: inuse %d\n", sock_prot_inuse(&udplite_prot));
seq_printf(seq, "RAW: inuse %d\n", sock_prot_inuse(&raw_prot));
seq_printf(seq, "FRAG: inuse %d memory %d\n",
ip_frag_nqueues(), ip_frag_mem());
return 0;

19
net/ipv6/proc.c
View File

@ -32,27 +32,16 @@
static struct proc_dir_entry *proc_net_devsnmp6;
static int fold_prot_inuse(struct proto *proto)
{
int res = 0;
int cpu;
for_each_possible_cpu(cpu)
res += proto->stats[cpu].inuse;
return res;
}
static int sockstat6_seq_show(struct seq_file *seq, void *v)
{
seq_printf(seq, "TCP6: inuse %d\n",
fold_prot_inuse(&tcpv6_prot));
sock_prot_inuse(&tcpv6_prot));
seq_printf(seq, "UDP6: inuse %d\n",
fold_prot_inuse(&udpv6_prot));
sock_prot_inuse(&udpv6_prot));
seq_printf(seq, "UDPLITE6: inuse %d\n",
fold_prot_inuse(&udplitev6_prot));
sock_prot_inuse(&udplitev6_prot));
seq_printf(seq, "RAW6: inuse %d\n",
fold_prot_inuse(&rawv6_prot));
sock_prot_inuse(&rawv6_prot));
seq_printf(seq, "FRAG6: inuse %d memory %d\n",
ip6_frag_nqueues(), ip6_frag_mem());
return 0;