From: Manish Kumar Singh <mk.singh@oracle.com>
To: Michal Kubecek <mkubecek@suse.cz>, Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Mahesh Bandewar (महेश बंडेवार)" <maheshb@google.com>,
linux-netdev <netdev@vger.kernel.org>,
"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: Thu, 25 Oct 2018 02:21:05 -0700 (PDT) [thread overview]
Message-ID: <bee18dd4-0012-44d0-9508-2987bfe521e5@default> (raw)
In-Reply-To: <20181023163825.GB22291@unicorn.suse.cz>
> -----Original Message-----
> From: Michal Kubecek [mailto:mkubecek@suse.cz]
> Sent: 23 अक्तूबर 2018 22:08
> To: Eric Dumazet
> Cc: Mahesh Bandewar (महेश बंडेवार); Manish Kumar Singh; linux-netdev; 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 Tue, Oct 23, 2018 at 06:26:14PM +0200, Michal Kubecek wrote:
> > On Tue, Oct 23, 2018 at 09:10:44AM -0700, Eric Dumazet wrote:
> > >
> > >
> > > On 10/23/2018 08:54 AM, Mahesh Bandewar (महेश बंडेवार) wrote:
> > >
> > > > Atomic operations are expensive (on certain architectures) and miimon
> > > > runs quite frequently. Is the added cost of these atomic operations
> > > > even worth just to avoid *duplicate info* messages? This seems like a
> > > > overkill!
> > >
> > > atomic_read() is a simple read, no atomic operation involved.
> > >
> > > Same remark for atomic_set()
> >
> > Which makes me wonder if the patch really needs atomic_t.
>
> IMHO it does not. AFAICS multiple instances of bond_mii_monitor() cannot
> run simultaneously for the same bond so that there doesn't seem to be
> anything to collide with. (And if they could, we would need to test and
> set the flag atomically in bond_miimon_inspect().)
>
Yes, Michal, we are inline with your understanding.
when the -original- patch was posted to upstream there was no -synchronization- nor -racing- addressing code was in read/write of this added filed, as we -never- saw need for either.
-only- writer of the added field is bond_mii_monitor.
-only- reader of the added field is bond_miimon_inspect.
-this writer & reader -never- can run concurrently.
-writer invokes the reader.
hence, imo uint_8 rtnl_needed is all what is needed; with bond_mii_monitor doing rtnl_needed = 1; and bond_miimon_inspect doing if rtnl_needed.
here is the gravity of the situation with multiple customers whose names including machine names redacted:
4353 May 31 02:38:57 hostname kernel: ixgbe 0000:03:00.0: removed PHC on p2p1
4354 May 31 02:38:57 hostname kernel: public: link status down for active interface p2p1, disabling it in 100 ms
4355 May 31 02:38:57 hostname kernel: public: link status down for active interface p2p1, disabling it in 100 ms
4356 May 31 02:38:57 hostname kernel: public: link status definitely down for interface p2p1, disabling it
4357 May 31 02:38:57 hostname kernel: public: making interface p2p2 the new active one
4358 May 31 02:38:59 hostname kernel: ixgbe 0000:03:00.0: registered PHC device on p2p1
4359 May 31 02:39:00 hostname kernel: ixgbe 0000:03:00.0 p2p1: NIC Link is Up 10 Gbps, Flow Control: RX/TX
4360 May 31 02:39:00 hostname kernel: public: link status up for interface p2p1, enabling it in 200 ms
4361 May 31 02:39:00 hostname kernel: public: link status definitely up for interface p2p1, 10000 Mbps full duplex
4362 May 31 02:45:37 hostname journal: Missed 217723 kernel messages
4363 May 31 02:45:37 hostname kernel: public: link status down for active interface p2p2, disabling it in 100 ms
---------------------
11000+ APPROX SAME REPEATED MESSAGES in second
---------------------
15877 May 31 02:45:37 hostname kernel: public: link status down for active interface p2p2, disabling it in 100 ms
15878 May 31 02:45:37 hostname kernel: public: link status definitely down for interface p2p2, disabling it
15879 May 31 02:45:37 hostname kernel: public: making interface p2p1 the new active one
Thanks,
Manish
> Michal Kubecek
next prev parent reply other threads:[~2018-10-25 9:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-23 15:29 [PATCH] bonding:avoid repeated display of same link status change 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 [this message]
2018-10-25 9:29 ` Michal Kubecek
2018-10-26 6:49 ` Manish Kumar Singh
2018-10-23 18:08 ` David Miller
-- strict thread matches above, loose matches on Subject: below --
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
2018-09-17 7:20 [PATCH] bonding: avoid " mk.singh
2018-09-17 14:38 ` Eric Dumazet
2018-09-18 5:05 ` Manish Kumar Singh
2018-09-18 14:00 ` Eric Dumazet
2018-09-24 7:05 ` Manish Kumar Singh
2018-10-22 7:29 ` Manish Kumar Singh
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