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Date: Tue, 15 Sep 2009 09:20:53 -0700
From: Jay Vosburgh <fubar@...ibm.com>
To: Jiri Pirko <jpirko@...hat.com>
cc: netdev@...r.kernel.org, davem@...emloft.net,
bonding-devel@...ts.sourceforge.net, nicolas.2p.debian@...e.fr
Subject: Re: [PATCH net-next-2.6] bonding: make ab_arp select active slaves as other modes
Jiri Pirko <jpirko@...hat.com> wrote:
>Fri, Sep 11, 2009 at 02:32:18AM CEST, fubar@...ibm.com wrote:
>>Jiri Pirko <jpirko@...hat.com> wrote:
>>
>>>When I was implementing primary_passive option (formely named primary_lazy) I've
>>>run into troubles with ab_arp. This is the only mode which is not using
>>>bond_select_active_slave() function to select active slave and instead it
>>>selects it itself. This seems to be not the right behaviour and it would be
>>>better to do it in bond_select_active_slave() for all cases. This patch makes
>>>this happen. Please review.
>>
>> Sorry for the delay in response; was out of the office.
>>
>> My first question is whether this affect the "current_arp_slave"
>>behavior, i.e., the round-robining of the ARP probes when no slaves are
>>active. Is that something you checked?
>
>Yes, according to my tests this behaves the same way as original code.
>How about your tests?
Yah, it seems to work like it should. I just have this nagging
feeling I'm forgetting something; that there was a reason that the ab
ARP was doing things differently. I sure don't remember, though;
probably just getting old.
The only nitpicks I see are a couple of changes that appear to
be just for style ("break" changed to "continue"; some code rearranged
in bond_find_best_slave, which is noted below) and one locking nit:
strictly speaking, curr_slave_lock should be held for read when
inspecting curr_active_slave. The place it happens, though, already
holds rtnl, and all changes to curr_active_slave happen under rtnl, so
it won't actually fail, but it's different than everywhere else.
I've been gnawing on getting rid of curr_slave_lock for a while;
I think it can go away, and be subsumed into the general bond->lock.
The curr_active_slave is (today, this didn't used to be true) only
changed under rtnl, but some other code does inspect it outside of rtnl.
-J
>Jirka
>
>>
>> I'll give this a test tomorrow as well.
>>
>> -J
>>
>>---
>> -Jay Vosburgh, IBM Linux Technology Center, fubar@...ibm.com
>>
>>>Signed-off-by: Jiri Pirko <jpirko@...hat.com>
>>>
>>>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>>>index 7c0e0bd..6ebd88d 100644
>>>--- a/drivers/net/bonding/bond_main.c
>>>+++ b/drivers/net/bonding/bond_main.c
>>>@@ -1093,15 +1093,8 @@ static struct slave *bond_find_best_slave(struct bonding *bond)
>>> return NULL; /* still no slave, return NULL */
>>> }
>>>
>>>- /*
>>>- * first try the primary link; if arping, a link must tx/rx
>>>- * traffic before it can be considered the curr_active_slave.
>>>- * also, we would skip slaves between the curr_active_slave
>>>- * and primary_slave that may be up and able to arp
>>>- */
>>> if ((bond->primary_slave) &&
>>>- (!bond->params.arp_interval) &&
>>>- (IS_UP(bond->primary_slave->dev))) {
>>>+ bond->primary_slave->link == BOND_LINK_UP) {
>>> new_active = bond->primary_slave;
>>> }
>>>
>>>@@ -1109,15 +1102,14 @@ static struct slave *bond_find_best_slave(struct bonding *bond)
>>> old_active = new_active;
>>>
>>> bond_for_each_slave_from(bond, new_active, i, old_active) {
>>>- if (IS_UP(new_active->dev)) {
>>>- if (new_active->link == BOND_LINK_UP) {
>>>- return new_active;
>>>- } else if (new_active->link == BOND_LINK_BACK) {
>>>- /* link up, but waiting for stabilization */
>>>- if (new_active->delay < mintime) {
>>>- mintime = new_active->delay;
>>>- bestslave = new_active;
>>>- }
>>>+ if (new_active->link == BOND_LINK_UP) {
>>>+ return new_active;
>>>+ } else if (new_active->link == BOND_LINK_BACK &&
>>>+ IS_UP(new_active->dev)) {
>>>+ /* link up, but waiting for stabilization */
>>>+ if (new_active->delay < mintime) {
>>>+ mintime = new_active->delay;
>>>+ bestslave = new_active;
>>
>> Is there a functional reason for rearranging this (i.e., did the
>>use of select_active_slave need this for some reason)?
>>
>>
>>> }
>>> }
>>> }
>>>@@ -2929,18 +2921,6 @@ static int bond_ab_arp_inspect(struct bonding *bond, int delta_in_ticks)
>>> }
>>> }
>>>
>>>- read_lock(&bond->curr_slave_lock);
>>>-
>>>- /*
>>>- * Trigger a commit if the primary option setting has changed.
>>>- */
>>>- if (bond->primary_slave &&
>>>- (bond->primary_slave != bond->curr_active_slave) &&
>>>- (bond->primary_slave->link == BOND_LINK_UP))
>>>- commit++;
>>>-
>>>- read_unlock(&bond->curr_slave_lock);
>>>-
>>> return commit;
>>> }
>>>
>>>@@ -2961,90 +2941,58 @@ static void bond_ab_arp_commit(struct bonding *bond, int delta_in_ticks)
>>> continue;
>>>
>>> case BOND_LINK_UP:
>>>- write_lock_bh(&bond->curr_slave_lock);
>>>-
>>>- if (!bond->curr_active_slave &&
>>>- time_before_eq(jiffies, dev_trans_start(slave->dev) +
>>>- delta_in_ticks)) {
>>>+ if ((!bond->curr_active_slave &&
>>>+ time_before_eq(jiffies,
>>>+ dev_trans_start(slave->dev) +
>>>+ delta_in_ticks)) ||
>>>+ bond->curr_active_slave != slave) {
>>> slave->link = BOND_LINK_UP;
>>>- bond_change_active_slave(bond, slave);
>>> bond->current_arp_slave = NULL;
>>>
>>> pr_info(DRV_NAME
>>>- ": %s: %s is up and now the "
>>>- "active interface\n",
>>>- bond->dev->name, slave->dev->name);
>>>-
>>>- } else if (bond->curr_active_slave != slave) {
>>>- /* this slave has just come up but we
>>>- * already have a current slave; this can
>>>- * also happen if bond_enslave adds a new
>>>- * slave that is up while we are searching
>>>- * for a new slave
>>>- */
>>>- slave->link = BOND_LINK_UP;
>>>- bond_set_slave_inactive_flags(slave);
>>>- bond->current_arp_slave = NULL;
>>>+ ": %s: link status definitely "
>>>+ "up for interface %s.\n",
>>>+ bond->dev->name, slave->dev->name);
>>>
>>>- pr_info(DRV_NAME
>>>- ": %s: backup interface %s is now up\n",
>>>- bond->dev->name, slave->dev->name);
>>>- }
>>>+ if (!bond->curr_active_slave ||
>>>+ (slave == bond->primary_slave))
>>>+ goto do_failover;
>>>
>>>- write_unlock_bh(&bond->curr_slave_lock);
>>>+ }
>>>
>>>- break;
>>>+ continue;
>>>
>>> case BOND_LINK_DOWN:
>>> if (slave->link_failure_count < UINT_MAX)
>>> slave->link_failure_count++;
>>>
>>> slave->link = BOND_LINK_DOWN;
>>>+ bond_set_slave_inactive_flags(slave);
>>>
>>>- if (slave == bond->curr_active_slave) {
>>>- pr_info(DRV_NAME
>>>- ": %s: link status down for active "
>>>- "interface %s, disabling it\n",
>>>- bond->dev->name, slave->dev->name);
>>>-
>>>- bond_set_slave_inactive_flags(slave);
>>>-
>>>- write_lock_bh(&bond->curr_slave_lock);
>>>-
>>>- bond_select_active_slave(bond);
>>>- if (bond->curr_active_slave)
>>>- bond->curr_active_slave->jiffies =
>>>- jiffies;
>>>-
>>>- write_unlock_bh(&bond->curr_slave_lock);
>>>+ pr_info(DRV_NAME
>>>+ ": %s: link status definitely down for "
>>>+ "interface %s, disabling it\n",
>>>+ bond->dev->name, slave->dev->name);
>>>
>>>+ if (slave == bond->curr_active_slave) {
>>> bond->current_arp_slave = NULL;
>>>-
>>>- } else if (slave->state == BOND_STATE_BACKUP) {
>>>- pr_info(DRV_NAME
>>>- ": %s: backup interface %s is now down\n",
>>>- bond->dev->name, slave->dev->name);
>>>-
>>>- bond_set_slave_inactive_flags(slave);
>>>+ goto do_failover;
>>> }
>>>- break;
>>>+
>>>+ continue;
>>>
>>> default:
>>> pr_err(DRV_NAME
>>> ": %s: impossible: new_link %d on slave %s\n",
>>> bond->dev->name, slave->new_link,
>>> slave->dev->name);
>>>+ continue;
>>> }
>>>- }
>>>
>>>- /*
>>>- * No race with changes to primary via sysfs, as we hold rtnl.
>>>- */
>>>- if (bond->primary_slave &&
>>>- (bond->primary_slave != bond->curr_active_slave) &&
>>>- (bond->primary_slave->link == BOND_LINK_UP)) {
>>>+do_failover:
>>>+ ASSERT_RTNL();
>>> write_lock_bh(&bond->curr_slave_lock);
>>>- bond_change_active_slave(bond, bond->primary_slave);
>>>+ bond_select_active_slave(bond);
>>> write_unlock_bh(&bond->curr_slave_lock);
>>> }
>>>
>>>--
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>>
>>
>>
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