From mboxrd@z Thu Jan 1 00:00:00 1970 From: Manish Kumar Singh Subject: RE: [PATCH] bonding: avoid repeated display of same link status change Date: Mon, 17 Sep 2018 22:05:44 -0700 (PDT) Message-ID: <78bf3185-fbd1-4a6c-ae32-70da0af2cbb4@default> References: <20180917072059.32657-1-mk.singh@oracle.com> <33a66a80-22ed-d6b3-f6b2-4463357c5ffa@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Cc: Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , "David S. Miller" , linux-kernel@vger.kernel.org To: Eric Dumazet , netdev@vger.kernel.org Return-path: In-Reply-To: <33a66a80-22ed-d6b3-f6b2-4463357c5ffa@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org > -----Original Message----- > From: Eric Dumazet [mailto:eric.dumazet@gmail.com] > Sent: 17 =E0=A4=B8=E0=A4=BF=E0=A4=A4=E0=A4=AE=E0=A5=8D=E0=A4=AC=E0=A4=B0 = 2018 20:08 > To: Manish Kumar Singh; netdev@vger.kernel.org > Cc: Jay Vosburgh; Veaceslav Falico; Andy Gospodarek; David S. Miller; lin= ux- > kernel@vger.kernel.org > Subject: Re: [PATCH] bonding: avoid repeated display of same link status > change >=20 >=20 >=20 > On 09/17/2018 12:20 AM, mk.singh@oracle.com wrote: > > From: Manish Kumar Singh > > > > 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 > > --- > > 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) > > =09=09=09bond_propose_link_state(slave, BOND_LINK_FAIL); > > =09=09=09commit++; > > =09=09=09slave->delay =3D bond->params.downdelay; > > -=09=09=09if (slave->delay) { > > +=09=09=09if (slave->delay && !bond->rtnl_needed) { > > =09=09=09=09netdev_info(bond->dev, "link status down for > %sinterface %s, disabling it in %d ms\n", > > =09=09=09=09=09 (BOND_MODE(bond) =3D=3D > > =09=09=09=09=09 BOND_MODE_ACTIVEBACKUP) ? > > @@ -2127,7 +2127,7 @@ static int bond_miimon_inspect(struct bonding > *bond) > > =09=09=09commit++; > > =09=09=09slave->delay =3D bond->params.updelay; > > > > -=09=09=09if (slave->delay) { > > +=09=09=09if (slave->delay && !bond->rtnl_needed) { > > =09=09=09=09netdev_info(bond->dev, "link status up for > interface %s, enabling it in %d ms\n", > > =09=09=09=09=09 slave->dev->name, > > =09=09=09=09=09 ignore_updelay ? 0 : > > @@ -2301,9 +2301,11 @@ static void bond_mii_monitor(struct > work_struct *work) > > =09=09if (!rtnl_trylock()) { > > =09=09=09delay =3D 1; > > =09=09=09should_notify_peers =3D false; > > +=09=09=09bond->rtnl_needed =3D true; >=20 > 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. T= here can't be two parallel instances of bond_miimon_inspect for a single = =C2=A0bonding driver instance at any given point of time. and only bond_mii= mon_inspect updates it. That=E2=80=99s why I think there is no need of any = synchronization here. =20 >=20 > 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 requireme= nt. we will change it. but; if time permits can you share more on "partic= ularly dangerous here, at least on some arches". F >=20 > > =09=09=09goto re_arm; > > =09=09} > > > > +=09=09bond->rtnl_needed =3D false; > > =09=09bond_for_each_slave(bond, slave, iter) { > > =09=09=09bond_commit_link_state(slave, > BOND_SLAVE_NOTIFY_LATER); > > =09=09} > > 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 { > > =09struct=09 dentry *debug_dir; > > #endif /* CONFIG_DEBUG_FS */ > > =09struct rtnl_link_stats64 bond_stats; > > +=09bool rtnl_needed; > > }; > > > > #define bond_slave_get_rcu(dev) \ > >