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rds: Use RCU for the bind lookup searches

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The RDS bind lookups are somewhat expensive in terms of CPU
time and locking overhead.  This commit changes them into a
faster RCU based hash tree instead of the rbtrees they were using
before.

On large NUMA systems it is a significant improvement.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2010-05-11 15:09:45 -07:00 committed by Andy Grover
parent e4c52c98e0
commit 38a4e5e613
4 changed files with 57 additions and 45 deletions
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8
net/rds/af_rds.c
View file

@ -72,7 +72,15 @@ static int rds_release(struct socket *sock)
* with the socket. */
rds_clear_recv_queue(rs);
rds_cong_remove_socket(rs);
/*
* the binding lookup hash uses rcu, we need to
* make sure we sychronize_rcu before we free our
* entry
*/
rds_remove_bound(rs);
synchronize_rcu();
rds_send_drop_to(rs, NULL);
rds_rdma_drop_keys(rs);
rds_notify_queue_get(rs, NULL);

90
net/rds/bind.c
View file

@ -34,45 +34,52 @@
#include <net/sock.h>
#include <linux/in.h>
#include <linux/if_arp.h>
#include <linux/jhash.h>
#include "rds.h"
/*
* XXX this probably still needs more work.. no INADDR_ANY, and rbtrees aren't
* particularly zippy.
*
* This is now called for every incoming frame so we arguably care much more
* about it than we used to.
*/
static DEFINE_RWLOCK(rds_bind_lock);
static struct rb_root rds_bind_tree = RB_ROOT;
#define BIND_HASH_SIZE 1024
static struct hlist_head bind_hash_table[BIND_HASH_SIZE];
static DEFINE_SPINLOCK(rds_bind_lock);
static struct rds_sock *rds_bind_tree_walk(__be32 addr, __be16 port,
struct rds_sock *insert)
static struct hlist_head *hash_to_bucket(__be32 addr, __be16 port)
{
return bind_hash_table + (jhash_2words((u32)addr, (u32)port, 0) &
(BIND_HASH_SIZE - 1));
}
static struct rds_sock *rds_bind_lookup(__be32 addr, __be16 port,
struct rds_sock *insert)
{
struct rb_node **p = &rds_bind_tree.rb_node;
struct rb_node *parent = NULL;
struct rds_sock *rs;
struct hlist_node *node;
struct hlist_head *head = hash_to_bucket(addr, port);
u64 cmp;
u64 needle = ((u64)be32_to_cpu(addr) << 32) | be16_to_cpu(port);
while (*p) {
parent = *p;
rs = rb_entry(parent, struct rds_sock, rs_bound_node);
rcu_read_lock();
hlist_for_each_entry_rcu(rs, node, head, rs_bound_node) {
cmp = ((u64)be32_to_cpu(rs->rs_bound_addr) << 32) |
be16_to_cpu(rs->rs_bound_port);
if (needle < cmp)
p = &(*p)->rb_left;
else if (needle > cmp)
p = &(*p)->rb_right;
else
if (cmp == needle) {
rcu_read_unlock();
return rs;
}
}
rcu_read_unlock();
if (insert) {
rb_link_node(&insert->rs_bound_node, parent, p);
rb_insert_color(&insert->rs_bound_node, &rds_bind_tree);
/*
* make sure our addr and port are set before
* we are added to the list, other people
* in rcu will find us as soon as the
* hlist_add_head_rcu is done
*/
insert->rs_bound_addr = addr;
insert->rs_bound_port = port;
rds_sock_addref(insert);
hlist_add_head_rcu(&insert->rs_bound_node, head);
}
return NULL;
}
@ -86,15 +93,13 @@ static struct rds_sock *rds_bind_tree_walk(__be32 addr, __be16 port,
struct rds_sock *rds_find_bound(__be32 addr, __be16 port)
{
struct rds_sock *rs;
unsigned long flags;
read_lock_irqsave(&rds_bind_lock, flags);
rs = rds_bind_tree_walk(addr, port, NULL);
rs = rds_bind_lookup(addr, port, NULL);
if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD))
rds_sock_addref(rs);
else
rs = NULL;
read_unlock_irqrestore(&rds_bind_lock, flags);
rdsdebug("returning rs %p for %pI4:%u\n", rs, &addr,
ntohs(port));
@ -116,28 +121,21 @@ static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
last = rover - 1;
}
write_lock_irqsave(&rds_bind_lock, flags);
spin_lock_irqsave(&rds_bind_lock, flags);
do {
if (rover == 0)
rover++;
if (!rds_bind_tree_walk(addr, cpu_to_be16(rover), rs)) {
*port = cpu_to_be16(rover);
if (!rds_bind_lookup(addr, cpu_to_be16(rover), rs)) {
*port = rs->rs_bound_port;
ret = 0;
rdsdebug("rs %p binding to %pI4:%d\n",
rs, &addr, (int)ntohs(*port));
break;
}
} while (rover++ != last);
if (ret == 0) {
rs->rs_bound_addr = addr;
rs->rs_bound_port = *port;
rds_sock_addref(rs);
rdsdebug("rs %p binding to %pI4:%d\n",
rs, &addr, (int)ntohs(*port));
}
write_unlock_irqrestore(&rds_bind_lock, flags);
spin_unlock_irqrestore(&rds_bind_lock, flags);
return ret;
}
@ -146,19 +144,19 @@ void rds_remove_bound(struct rds_sock *rs)
{
unsigned long flags;
write_lock_irqsave(&rds_bind_lock, flags);
spin_lock_irqsave(&rds_bind_lock, flags);
if (rs->rs_bound_addr) {
rdsdebug("rs %p unbinding from %pI4:%d\n",
rs, &rs->rs_bound_addr,
ntohs(rs->rs_bound_port));
rb_erase(&rs->rs_bound_node, &rds_bind_tree);
hlist_del_init_rcu(&rs->rs_bound_node);
rds_sock_put(rs);
rs->rs_bound_addr = 0;
}
write_unlock_irqrestore(&rds_bind_lock, flags);
spin_unlock_irqrestore(&rds_bind_lock, flags);
}
int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
@ -198,5 +196,9 @@ int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
out:
release_sock(sk);
/* we might have called rds_remove_bound on error */
if (ret)
synchronize_rcu();
return ret;
}

2
net/rds/ib_rdma.c
View file

@ -303,6 +303,8 @@ static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
goto out_no_cigar;
}
memset(ibmr, 0, sizeof(*ibmr));
ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
(IB_ACCESS_LOCAL_WRITE |
IB_ACCESS_REMOTE_READ |

2
net/rds/rds.h
View file

@ -452,7 +452,7 @@ struct rds_sock {
* bound_addr used for both incoming and outgoing, no INADDR_ANY
* support.
*/
struct rb_node rs_bound_node;
struct hlist_node rs_bound_node;
__be32 rs_bound_addr;
__be32 rs_conn_addr;
__be16 rs_bound_port;