From: Manish Kumar Singh <mk.singh@oracle.com>
To: Eric Dumazet <eric.dumazet@gmail.com>, netdev@vger.kernel.org
Cc: Jay Vosburgh <j.vosburgh@gmail.com>,
Veaceslav Falico <vfalico@gmail.com>,
Andy Gospodarek <andy@greyhouse.net>,
"David S. Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org
Subject: RE: [PATCH] bonding: avoid repeated display of same link status change
Date: Mon, 17 Sep 2018 22:05:44 -0700 (PDT) [thread overview]
Message-ID: <78bf3185-fbd1-4a6c-ae32-70da0af2cbb4@default> (raw)
In-Reply-To: <33a66a80-22ed-d6b3-f6b2-4463357c5ffa@gmail.com>
> -----Original Message-----
> From: Eric Dumazet [mailto:eric.dumazet@gmail.com]
> Sent: 17 सितम्बर 2018 20:08
> To: Manish Kumar Singh; netdev@vger.kernel.org
> Cc: Jay Vosburgh; Veaceslav Falico; Andy Gospodarek; David S. Miller; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH] bonding: avoid repeated display of same link status
> change
>
>
>
> On 09/17/2018 12:20 AM, mk.singh@oracle.com wrote:
> > From: Manish Kumar Singh <mk.singh@oracle.com>
> >
> > When link status change needs to be committed and rtnl lock couldn't be
> > taken, avoid redisplay of same link status change message.
> >
> > Signed-off-by: Manish Kumar Singh <mk.singh@oracle.com>
> > ---
> > drivers/net/bonding/bond_main.c | 6 ++++--
> > include/net/bonding.h | 1 +
> > 2 files changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/bonding/bond_main.c
> b/drivers/net/bonding/bond_main.c
> > index 217b790d22ed..fb4e3aff1677 100644
> > --- a/drivers/net/bonding/bond_main.c
> > +++ b/drivers/net/bonding/bond_main.c
> > @@ -2087,7 +2087,7 @@ static int bond_miimon_inspect(struct bonding
> *bond)
> > bond_propose_link_state(slave, BOND_LINK_FAIL);
> > commit++;
> > slave->delay = bond->params.downdelay;
> > - if (slave->delay) {
> > + if (slave->delay && !bond->rtnl_needed) {
> > netdev_info(bond->dev, "link status down for
> %sinterface %s, disabling it in %d ms\n",
> > (BOND_MODE(bond) ==
> > BOND_MODE_ACTIVEBACKUP) ?
> > @@ -2127,7 +2127,7 @@ static int bond_miimon_inspect(struct bonding
> *bond)
> > commit++;
> > slave->delay = bond->params.updelay;
> >
> > - if (slave->delay) {
> > + if (slave->delay && !bond->rtnl_needed) {
> > netdev_info(bond->dev, "link status up for
> interface %s, enabling it in %d ms\n",
> > slave->dev->name,
> > ignore_updelay ? 0 :
> > @@ -2301,9 +2301,11 @@ static void bond_mii_monitor(struct
> work_struct *work)
> > if (!rtnl_trylock()) {
> > delay = 1;
> > should_notify_peers = false;
> > + bond->rtnl_needed = true;
>
> How can you set a shared variable with no synchronization ?
Thanks Eric for reviewing the patch. rtnl_needed is not a shared variable, it is part of bonding structure, that is one per bonding driver instance. There can't be two parallel instances of bond_miimon_inspect for a single bonding driver instance at any given point of time. and only bond_miimon_inspect updates it. That’s why I think there is no need of any synchronization here.
>
> A bool is particularly dangerous here, at least on some arches.
Thank you for cautioning us on bool usage. even a u8 can meet our requirement. we will change it. but; if time permits can you share more on "particularly dangerous here, at least on some arches".
F
>
> > goto re_arm;
> > }
> >
> > + bond->rtnl_needed = false;
> > bond_for_each_slave(bond, slave, iter) {
> > bond_commit_link_state(slave,
> BOND_SLAVE_NOTIFY_LATER);
> > }
> > diff --git a/include/net/bonding.h b/include/net/bonding.h
> > index 808f1d167349..50d61cf77855 100644
> > --- a/include/net/bonding.h
> > +++ b/include/net/bonding.h
> > @@ -234,6 +234,7 @@ struct bonding {
> > struct dentry *debug_dir;
> > #endif /* CONFIG_DEBUG_FS */
> > struct rtnl_link_stats64 bond_stats;
> > + bool rtnl_needed;
> > };
> >
> > #define bond_slave_get_rcu(dev) \
> >
next prev parent reply other threads:[~2018-09-18 5:06 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-17 7:20 [PATCH] bonding: avoid repeated display of same link status change mk.singh
2018-09-17 14:38 ` Eric Dumazet
2018-09-18 5:05 ` Manish Kumar Singh [this message]
2018-09-18 14:00 ` Eric Dumazet
2018-09-24 7:05 ` Manish Kumar Singh
2018-10-22 7:29 ` Manish Kumar Singh
2018-10-23 15:29 [PATCH] bonding:avoid " mk.singh
2018-10-23 15:54 ` Mahesh Bandewar (महेश बंडेवार)
2018-10-23 16:10 ` Eric Dumazet
2018-10-23 16:26 ` Michal Kubecek
2018-10-23 16:38 ` Michal Kubecek
2018-10-25 9:21 ` Manish Kumar Singh
2018-10-25 9:29 ` Michal Kubecek
2018-10-26 6:49 ` Manish Kumar Singh
2018-10-23 18:08 ` David Miller
2018-10-31 10:57 mk.singh
2018-11-03 6:31 ` David Miller
2018-11-04 19:41 ` Michal Kubecek
2018-11-20 10:41 ` Manish Kumar Singh
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