From: Andrew Lunn <andrew@lunn.ch>
To: Michal Kubecek <mkubecek@suse.cz>
Cc: Tariq Toukan <tariqt@mellanox.com>,
"John W. Linville" <linville@tuxdriver.com>,
netdev@vger.kernel.org, Eran Ben Elisha <eranbe@mellanox.com>,
Aya Levin <ayal@mellanox.com>
Subject: Re: [PATCH ethtool] ethtool: Add support for 200Gbps (50Gbps per lane) link mode
Date: Sun, 24 Feb 2019 21:43:36 +0100 [thread overview]
Message-ID: <20190224204336.GC20855@lunn.ch> (raw)
In-Reply-To: <20190224203333.GC1914@unicorn.suse.cz>
> > Hi Michal
> >
> > So are you doing a read/modify/write? In that case, off/on makes
> > sense. For a pure write, i don't see the need for off/on.
>
> When using netlink interface, the read/modify/write cycle is limited to
> kernel code and is done under rtnl_lock. The netlink interface allows
> userspace to send only attributes it wants to change and for bit sets
> (like link modes) to tell kernel which bits it wants to change so that
> there is no need to read current values first (and open a race window).
Nice.
But it would still be good to get feedback from people who use this
more often. I guess that is top of rack switches with all these odd
link modes.
Andrew
next prev parent reply other threads:[~2019-02-24 20:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-24 15:08 [PATCH ethtool] ethtool: Add support for 200Gbps (50Gbps per lane) link mode Tariq Toukan
2019-02-24 16:47 ` Andrew Lunn
2019-02-24 18:40 ` Michal Kubecek
2019-02-24 19:40 ` Andrew Lunn
2019-02-24 20:33 ` Michal Kubecek
2019-02-24 20:43 ` Andrew Lunn [this message]
2019-02-25 15:30 ` Tariq Toukan
2019-02-25 12:42 ` Aya Levin
2019-02-24 18:11 ` Michal Kubecek
2019-02-25 11:48 ` Michal Kubecek
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