From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Ahern <dsa@cumulusnetworks.com>
Subject: Re: [patch net-next 12/15] ipv4: fib: Notify about nexthop status
 changes
Date: Wed, 8 Feb 2017 11:05:54 -0700
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Cc: Jiri Pirko <jiri@resnulli.us>, netdev@vger.kernel.org,
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To: Ido Schimmel <idosch@mellanox.com>,
        Andy Gospodarek <andy@greyhouse.net>
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On 2/8/17 8:32 AM, Ido Schimmel wrote:
> In the case of multipath routes, if some of the nexthops can be
> reflected, then we do so, but periodically ask the kernel to try and
> resolve the others. Otherwise, these nexthops will never be resolved, as
> the kernel doesn't see the packets hitting the multipath route and
> therefore lacks the motivation to resolve its nexthops.

It should get the motivation once the neigh entry is cleaned up. That
can take a long time based on gc settings, but it can also happen from
the remote side if it sends an arp message.