From: David Ahern <dsahern@kernel.org>
To: Florent Fourcot <florent.fourcot@wifirst.fr>, netdev@vger.kernel.org
Cc: Eric Dumazet <edumazet@google.com>,
Daniel Borkmann <daniel@iogearbox.net>
Subject: Re: [PATCH v2 net-next] net: neigh: add netlink filtering based on LLADDR for dump
Date: Wed, 25 May 2022 09:19:33 -0600 [thread overview]
Message-ID: <d8a28a59-79ca-e1fc-7768-a91f8033ce0e@kernel.org> (raw)
In-Reply-To: <af7b9565-ca70-0c36-4695-a0705825468d@wifirst.fr>
On 5/24/22 2:49 PM, Florent Fourcot wrote:
> Hello David,
>
> This patch has been marked as rejected after your comment.
> Could you perhaps have a second look on it? And on my response above? I
> still think that my patch is relevant and add a currently not available
> feature.
>
> I can work on alternative approach if necessary. Since neighbour tables
> are sometimes huge, performance overhead of userspace filtering for a
> simple MAC address lookup is currently high. And GET does not provide
> same feature.
>
Kernel side filtering has always been kept to simple, coarse grained
checks - like a device index or upper device index. It's a fine line
managing kernel cycles holding the rtnl vs cycles shipping the data to
userspace. e.g., a memcmp has a higher cost than a dev->index
comparison. I see the point about GET only - potential for many matches
and a lookup of the ll address is basically a filtered dump. Mixed
thoughts on whether this should be merged.
next prev parent reply other threads:[~2022-05-25 15:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-09 20:56 [PATCH v2 net-next] net: neigh: add netlink filtering based on LLADDR for dump Florent Fourcot
2022-05-10 1:38 ` David Ahern
2022-05-10 6:54 ` Florent Fourcot
2022-05-24 20:49 ` Florent Fourcot
2022-05-25 15:19 ` David Ahern [this message]
2022-06-09 7:58 ` Florent Fourcot
2022-06-09 15:38 ` David Ahern
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