From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Gospodarek Subject: Re: [PATCH 2/4] bonding: make sure tx and rx hash tables stay in sync when using alb mode Date: Fri, 18 Sep 2009 11:36:22 -0400 Message-ID: <20090918153622.GX8515@gospo.rdu.redhat.com> References: <20090911211112.GR8515@gospo.rdu.redhat.com> <27763.1253144169@death.nxdomain.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, bonding-devel@lists.sourceforge.net To: Jay Vosburgh Return-path: Received: from mx1.redhat.com ([209.132.183.28]:54816 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750805AbZIRPgn (ORCPT ); Fri, 18 Sep 2009 11:36:43 -0400 Content-Disposition: inline In-Reply-To: <27763.1253144169@death.nxdomain.ibm.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Sep 16, 2009 at 04:36:09PM -0700, Jay Vosburgh wrote: > Andy Gospodarek wrote: > > > > >Subject: [PATCH] bonding: make sure tx and rx hash tables stay in sync when using alb mode > > When testing this, I'm getting a lockdep warning. It appears to > be unhappy that tlb_choose_channel acquires the tx / rx hash table locks > in the order tx then rx, but rlb_choose_channel -> alb_get_best_slave > acquires the locks in the other order. I applied all four patches, but > it looks like the change that trips lockdep is in this patch (#2). > > I haven't gotten an actual deadlock from this, although it seems > plausible if there are two cpus in bond_alb_xmit at the same time, and > one of them is sending an ARP. > > One fairly straightforward fix would be to combine the rx and tx > hash table locks into a single lock. I suspect that wouldn't have any > real performance penalty, since the rx hash table lock is generally not > acquired very often (unlike the tx lock, which is taken for every packet > that goes out). > > Also, FYI, two of the four patches had trailing whitespace. I > believe it was #2 and #4. > > Thoughts? Jay, This patch should address both the the deadlock and whitespace conerns. I ran a kernel with LOCKDEP enabled and saw no warnings while passing traffic on the bond while pulling cables and while removing the module. Here it is.... [PATCH] bonding: make sure tx and rx hash tables stay in sync when using alb mode I noticed that it was easy for alb (mode 6) bonding to get into a state where the tx hash-table and rx hash-table are out of sync (there is really nothing to keep them synchronized), and we will transmit traffic destined for a host on one slave and send ARP frames to the same slave from another interface using a different source MAC. There is no compelling reason to do this, so this patch makes sure the rx hash-table changes whenever the tx hash-table is updated based on device load. This patch also drops the code that does rlb re-balancing since the balancing will not be controlled by the tx hash-table based on transmit load. In order to address an issue found with the initial patch, I have also combined the rx and tx hash table lock into a single lock. This will facilitate moving these into a single table at some point. --- drivers/net/bonding/bond_alb.c | 203 +++++++++++++++------------------------- drivers/net/bonding/bond_alb.h | 3 +- 2 files changed, 75 insertions(+), 131 deletions(-) diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c index bcf25c6..04b7055 100644 --- a/drivers/net/bonding/bond_alb.c +++ b/drivers/net/bonding/bond_alb.c @@ -111,6 +111,7 @@ static inline struct arp_pkt *arp_pkt(const struct sk_buff *skb) /* Forward declaration */ static void alb_send_learning_packets(struct slave *slave, u8 mac_addr[]); +static struct slave *alb_get_best_slave(struct bonding *bond, u32 hash_index); static inline u8 _simple_hash(const u8 *hash_start, int hash_size) { @@ -124,18 +125,18 @@ static inline u8 _simple_hash(const u8 *hash_start, int hash_size) return hash; } -/*********************** tlb specific functions ***************************/ - -static inline void _lock_tx_hashtbl(struct bonding *bond) +/********************* hash table lock functions *************************/ +static inline void _lock_hashtbl(struct bonding *bond) { - spin_lock_bh(&(BOND_ALB_INFO(bond).tx_hashtbl_lock)); + spin_lock_bh(&(BOND_ALB_INFO(bond).hashtbl_lock)); } -static inline void _unlock_tx_hashtbl(struct bonding *bond) +static inline void _unlock_hashtbl(struct bonding *bond) { - spin_unlock_bh(&(BOND_ALB_INFO(bond).tx_hashtbl_lock)); + spin_unlock_bh(&(BOND_ALB_INFO(bond).hashtbl_lock)); } +/*********************** tlb specific functions ***************************/ /* Caller must hold tx_hashtbl lock */ static inline void tlb_init_table_entry(struct tlb_client_info *entry, int save_load) { @@ -163,7 +164,7 @@ static void tlb_clear_slave(struct bonding *bond, struct slave *slave, int save_ struct tlb_client_info *tx_hash_table; u32 index; - _lock_tx_hashtbl(bond); + _lock_hashtbl(bond); /* clear slave from tx_hashtbl */ tx_hash_table = BOND_ALB_INFO(bond).tx_hashtbl; @@ -180,7 +181,7 @@ static void tlb_clear_slave(struct bonding *bond, struct slave *slave, int save_ tlb_init_slave(slave); - _unlock_tx_hashtbl(bond); + _unlock_hashtbl(bond); } /* Must be called before starting the monitor timer */ @@ -191,7 +192,7 @@ static int tlb_initialize(struct bonding *bond) struct tlb_client_info *new_hashtbl; int i; - spin_lock_init(&(bond_info->tx_hashtbl_lock)); + spin_lock_init(&(bond_info->hashtbl_lock)); new_hashtbl = kzalloc(size, GFP_KERNEL); if (!new_hashtbl) { @@ -200,7 +201,7 @@ static int tlb_initialize(struct bonding *bond) bond->dev->name); return -1; } - _lock_tx_hashtbl(bond); + _lock_hashtbl(bond); bond_info->tx_hashtbl = new_hashtbl; @@ -208,7 +209,7 @@ static int tlb_initialize(struct bonding *bond) tlb_init_table_entry(&bond_info->tx_hashtbl[i], 1); } - _unlock_tx_hashtbl(bond); + _unlock_hashtbl(bond); return 0; } @@ -218,12 +219,12 @@ static void tlb_deinitialize(struct bonding *bond) { struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond)); - _lock_tx_hashtbl(bond); + _lock_hashtbl(bond); kfree(bond_info->tx_hashtbl); bond_info->tx_hashtbl = NULL; - _unlock_tx_hashtbl(bond); + _unlock_hashtbl(bond); } /* Caller must hold bond lock for read */ @@ -264,24 +265,6 @@ static struct slave *tlb_get_least_loaded_slave(struct bonding *bond) return least_loaded; } -/* Caller must hold bond lock for read and hashtbl lock */ -static struct slave *tlb_get_best_slave(struct bonding *bond, u32 hash_index) -{ - struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond)); - struct tlb_client_info *tx_hash_table = bond_info->tx_hashtbl; - struct slave *last_slave = tx_hash_table[hash_index].last_slave; - struct slave *next_slave = NULL; - - if (last_slave && SLAVE_IS_OK(last_slave)) { - /* Use the last slave listed in the tx hashtbl if: - the last slave currently is essentially unloaded. */ - if (SLAVE_TLB_INFO(last_slave).load < 10) - next_slave = last_slave; - } - - return next_slave ? next_slave : tlb_get_least_loaded_slave(bond); -} - /* Caller must hold bond lock for read */ static struct slave *tlb_choose_channel(struct bonding *bond, u32 hash_index, u32 skb_len) { @@ -289,13 +272,12 @@ static struct slave *tlb_choose_channel(struct bonding *bond, u32 hash_index, u3 struct tlb_client_info *hash_table; struct slave *assigned_slave; - _lock_tx_hashtbl(bond); + _lock_hashtbl(bond); hash_table = bond_info->tx_hashtbl; assigned_slave = hash_table[hash_index].tx_slave; if (!assigned_slave) { - assigned_slave = tlb_get_best_slave(bond, hash_index); - + assigned_slave = alb_get_best_slave(bond, hash_index); if (assigned_slave) { struct tlb_slave_info *slave_info = &(SLAVE_TLB_INFO(assigned_slave)); @@ -319,20 +301,52 @@ static struct slave *tlb_choose_channel(struct bonding *bond, u32 hash_index, u3 hash_table[hash_index].tx_bytes += skb_len; } - _unlock_tx_hashtbl(bond); + _unlock_hashtbl(bond); return assigned_slave; } /*********************** rlb specific functions ***************************/ -static inline void _lock_rx_hashtbl(struct bonding *bond) + +/* Caller must hold bond lock for read and hashtbl lock */ +static struct slave *rlb_update_rx_table(struct bonding *bond, struct slave *next_slave, u32 hash_index) { - spin_lock_bh(&(BOND_ALB_INFO(bond).rx_hashtbl_lock)); + struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond)); + + /* check rlb table and correct it if wrong */ + if (bond_info->rlb_enabled) { + struct rlb_client_info *rx_client_info = &(bond_info->rx_hashtbl[hash_index]); + + /* if the new slave computed by tlb checks doesn't match rlb, stop rlb from using it */ + if (next_slave && (next_slave != rx_client_info->slave)) + rx_client_info->slave = next_slave; + } + return next_slave; } -static inline void _unlock_rx_hashtbl(struct bonding *bond) +/* Caller must hold bond lock for read and hashtbl lock */ +static struct slave *alb_get_best_slave(struct bonding *bond, u32 hash_index) { - spin_unlock_bh(&(BOND_ALB_INFO(bond).rx_hashtbl_lock)); + struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond)); + struct tlb_client_info *tx_hash_table = bond_info->tx_hashtbl; + struct slave *last_slave = tx_hash_table[hash_index].last_slave; + struct slave *next_slave = NULL; + + /* presume the next slave will be the least loaded one */ + next_slave = tlb_get_least_loaded_slave(bond); + + if (last_slave && SLAVE_IS_OK(last_slave)) { + /* Use the last slave listed in the tx hashtbl if: + the last slave currently is essentially unloaded. */ + if (SLAVE_TLB_INFO(last_slave).load < 10) + next_slave = last_slave; + } + + /* update the rlb hashtbl if there was a previous entry */ + if (bond_info->rlb_enabled) + rlb_update_rx_table(bond, next_slave, hash_index); + + return next_slave; } /* when an ARP REPLY is received from a client update its info @@ -344,7 +358,7 @@ static void rlb_update_entry_from_arp(struct bonding *bond, struct arp_pkt *arp) struct rlb_client_info *client_info; u32 hash_index; - _lock_rx_hashtbl(bond); + _lock_hashtbl(bond); hash_index = _simple_hash((u8*)&(arp->ip_src), sizeof(arp->ip_src)); client_info = &(bond_info->rx_hashtbl[hash_index]); @@ -358,7 +372,7 @@ static void rlb_update_entry_from_arp(struct bonding *bond, struct arp_pkt *arp) bond_info->rx_ntt = 1; } - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); } static int rlb_arp_recv(struct sk_buff *skb, struct net_device *bond_dev, struct packet_type *ptype, struct net_device *orig_dev) @@ -402,38 +416,6 @@ out: return res; } -/* Caller must hold bond lock for read */ -static struct slave *rlb_next_rx_slave(struct bonding *bond) -{ - struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond)); - struct slave *rx_slave, *slave, *start_at; - int i = 0; - - if (bond_info->next_rx_slave) { - start_at = bond_info->next_rx_slave; - } else { - start_at = bond->first_slave; - } - - rx_slave = NULL; - - bond_for_each_slave_from(bond, slave, i, start_at) { - if (SLAVE_IS_OK(slave)) { - if (!rx_slave) { - rx_slave = slave; - } else if (slave->speed > rx_slave->speed) { - rx_slave = slave; - } - } - } - - if (rx_slave) { - bond_info->next_rx_slave = rx_slave->next; - } - - return rx_slave; -} - /* teach the switch the mac of a disabled slave * on the primary for fault tolerance * @@ -468,14 +450,14 @@ static void rlb_clear_slave(struct bonding *bond, struct slave *slave) u32 index, next_index; /* clear slave from rx_hashtbl */ - _lock_rx_hashtbl(bond); + _lock_hashtbl(bond); rx_hash_table = bond_info->rx_hashtbl; index = bond_info->rx_hashtbl_head; for (; index != RLB_NULL_INDEX; index = next_index) { next_index = rx_hash_table[index].next; if (rx_hash_table[index].slave == slave) { - struct slave *assigned_slave = rlb_next_rx_slave(bond); + struct slave *assigned_slave = alb_get_best_slave(bond, index); if (assigned_slave) { rx_hash_table[index].slave = assigned_slave; @@ -499,7 +481,7 @@ static void rlb_clear_slave(struct bonding *bond, struct slave *slave) } } - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); write_lock_bh(&bond->curr_slave_lock); @@ -558,7 +540,7 @@ static void rlb_update_rx_clients(struct bonding *bond) struct rlb_client_info *client_info; u32 hash_index; - _lock_rx_hashtbl(bond); + _lock_hashtbl(bond); hash_index = bond_info->rx_hashtbl_head; for (; hash_index != RLB_NULL_INDEX; hash_index = client_info->next) { @@ -576,7 +558,7 @@ static void rlb_update_rx_clients(struct bonding *bond) */ bond_info->rlb_update_delay_counter = RLB_UPDATE_DELAY; - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); } /* The slave was assigned a new mac address - update the clients */ @@ -587,7 +569,7 @@ static void rlb_req_update_slave_clients(struct bonding *bond, struct slave *sla int ntt = 0; u32 hash_index; - _lock_rx_hashtbl(bond); + _lock_hashtbl(bond); hash_index = bond_info->rx_hashtbl_head; for (; hash_index != RLB_NULL_INDEX; hash_index = client_info->next) { @@ -607,7 +589,7 @@ static void rlb_req_update_slave_clients(struct bonding *bond, struct slave *sla bond_info->rlb_update_retry_counter = RLB_UPDATE_RETRY; } - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); } /* mark all clients using src_ip to be updated */ @@ -617,7 +599,7 @@ static void rlb_req_update_subnet_clients(struct bonding *bond, __be32 src_ip) struct rlb_client_info *client_info; u32 hash_index; - _lock_rx_hashtbl(bond); + _lock_hashtbl(bond); hash_index = bond_info->rx_hashtbl_head; for (; hash_index != RLB_NULL_INDEX; hash_index = client_info->next) { @@ -643,7 +625,7 @@ static void rlb_req_update_subnet_clients(struct bonding *bond, __be32 src_ip) } } - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); } /* Caller must hold both bond and ptr locks for read */ @@ -655,7 +637,7 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon struct rlb_client_info *client_info; u32 hash_index = 0; - _lock_rx_hashtbl(bond); + _lock_hashtbl(bond); hash_index = _simple_hash((u8 *)&arp->ip_dst, sizeof(arp->ip_src)); client_info = &(bond_info->rx_hashtbl[hash_index]); @@ -671,7 +653,7 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon assigned_slave = client_info->slave; if (assigned_slave) { - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); return assigned_slave; } } else { @@ -687,7 +669,7 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon } } /* assign a new slave */ - assigned_slave = rlb_next_rx_slave(bond); + assigned_slave = alb_get_best_slave(bond, hash_index); if (assigned_slave) { client_info->ip_src = arp->ip_src; @@ -723,7 +705,7 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon } } - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); return assigned_slave; } @@ -771,36 +753,6 @@ static struct slave *rlb_arp_xmit(struct sk_buff *skb, struct bonding *bond) return tx_slave; } -/* Caller must hold bond lock for read */ -static void rlb_rebalance(struct bonding *bond) -{ - struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond)); - struct slave *assigned_slave; - struct rlb_client_info *client_info; - int ntt; - u32 hash_index; - - _lock_rx_hashtbl(bond); - - ntt = 0; - hash_index = bond_info->rx_hashtbl_head; - for (; hash_index != RLB_NULL_INDEX; hash_index = client_info->next) { - client_info = &(bond_info->rx_hashtbl[hash_index]); - assigned_slave = rlb_next_rx_slave(bond); - if (assigned_slave && (client_info->slave != assigned_slave)) { - client_info->slave = assigned_slave; - client_info->ntt = 1; - ntt = 1; - } - } - - /* update the team's flag only after the whole iteration */ - if (ntt) { - bond_info->rx_ntt = 1; - } - _unlock_rx_hashtbl(bond); -} - /* Caller must hold rx_hashtbl lock */ static void rlb_init_table_entry(struct rlb_client_info *entry) { @@ -817,8 +769,6 @@ static int rlb_initialize(struct bonding *bond) int size = RLB_HASH_TABLE_SIZE * sizeof(struct rlb_client_info); int i; - spin_lock_init(&(bond_info->rx_hashtbl_lock)); - new_hashtbl = kmalloc(size, GFP_KERNEL); if (!new_hashtbl) { printk(KERN_ERR DRV_NAME @@ -826,7 +776,7 @@ static int rlb_initialize(struct bonding *bond) bond->dev->name); return -1; } - _lock_rx_hashtbl(bond); + _lock_hashtbl(bond); bond_info->rx_hashtbl = new_hashtbl; @@ -836,7 +786,7 @@ static int rlb_initialize(struct bonding *bond) rlb_init_table_entry(bond_info->rx_hashtbl + i); } - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); /*initialize packet type*/ pk_type->type = cpu_to_be16(ETH_P_ARP); @@ -855,13 +805,13 @@ static void rlb_deinitialize(struct bonding *bond) dev_remove_pack(&(bond_info->rlb_pkt_type)); - _lock_rx_hashtbl(bond); + _lock_hashtbl(bond); kfree(bond_info->rx_hashtbl); bond_info->rx_hashtbl = NULL; bond_info->rx_hashtbl_head = RLB_NULL_INDEX; - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); } static void rlb_clear_vlan(struct bonding *bond, unsigned short vlan_id) @@ -869,7 +819,7 @@ static void rlb_clear_vlan(struct bonding *bond, unsigned short vlan_id) struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond)); u32 curr_index; - _lock_rx_hashtbl(bond); + _lock_hashtbl(bond); curr_index = bond_info->rx_hashtbl_head; while (curr_index != RLB_NULL_INDEX) { @@ -894,7 +844,7 @@ static void rlb_clear_vlan(struct bonding *bond, unsigned short vlan_id) curr_index = next_index; } - _unlock_rx_hashtbl(bond); + _unlock_hashtbl(bond); } /*********************** tlb/rlb shared functions *********************/ @@ -1521,11 +1471,6 @@ void bond_alb_monitor(struct work_struct *work) read_lock(&bond->lock); } - if (bond_info->rlb_rebalance) { - bond_info->rlb_rebalance = 0; - rlb_rebalance(bond); - } - /* check if clients need updating */ if (bond_info->rx_ntt) { if (bond_info->rlb_update_delay_counter) { diff --git a/drivers/net/bonding/bond_alb.h b/drivers/net/bonding/bond_alb.h index b65fd29..09d755a 100644 --- a/drivers/net/bonding/bond_alb.h +++ b/drivers/net/bonding/bond_alb.h @@ -90,7 +90,7 @@ struct tlb_slave_info { struct alb_bond_info { struct timer_list alb_timer; struct tlb_client_info *tx_hashtbl; /* Dynamically allocated */ - spinlock_t tx_hashtbl_lock; + spinlock_t hashtbl_lock; /* lock for both tables */ u32 unbalanced_load; int tx_rebalance_counter; int lp_counter; @@ -98,7 +98,6 @@ struct alb_bond_info { int rlb_enabled; struct packet_type rlb_pkt_type; struct rlb_client_info *rx_hashtbl; /* Receive hash table */ - spinlock_t rx_hashtbl_lock; u32 rx_hashtbl_head; u8 rx_ntt; /* flag - need to transmit * to all rx clients -- 1.5.5.6