Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 38a4e5e6 authored by Chris Mason's avatar Chris Mason Committed by Andy Grover
Browse files

rds: Use RCU for the bind lookup searches 



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: default avatarChris Mason <chris.mason@oracle.com>
parent e4c52c98

net/rds/af_rds.c

+8 −0
Original line number Diff line number Diff line
@@ -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);

net/rds/bind.c

+46 −44
Original line number Diff line number Diff line
@@ -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 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_tree_walk(__be32 addr, __be16 port,

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;

			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));

			break;

		}

	} while (rover++ != last);



	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;

}

net/rds/ib_rdma.c

+2 −0
Original line number Diff line number Diff line
@@ -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 |

net/rds/rds.h

+1 −1
Original line number Diff line number Diff line
@@ -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;