netdev - Re: [PATCH net-next v6] rtnetlink: Support fine-grained netdevice bulk deletion

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Date:   Thu, 6 Jan 2022 21:54:36 +0200
From:   Lahav Schlesinger <lschlesinger@...venets.com>
To:     David Ahern <dsahern@...il.com>
Cc:     Eric Dumazet <eric.dumazet@...il.com>, netdev@...r.kernel.org,
        kuba@...nel.org, idosch@...sch.org, nicolas.dichtel@...nd.com,
        nikolay@...dia.com
Subject: Re: [PATCH net-next v6] rtnetlink: Support fine-grained netdevice
 bulk deletion

On Wed, Jan 05, 2022 at 09:09:34AM -0700, David Ahern wrote:
> CAUTION: External E-Mail - Use caution with links and attachments
>
>
> On 1/4/22 5:18 PM, David Ahern wrote:
> > On 1/4/22 1:40 PM, Lahav Schlesinger wrote:
> >> I tried using dev->unreg_list but it doesn't work e.g. for veth pairs
> >> where ->dellink() of a veth automatically adds the peer. Therefore if
> >> @ifindices contains both peers then the first ->dellink() will remove
> >> the next device from @list_kill. This caused a page fault when
> >> @list_kill was further iterated on.
> >
> > make sure you add a selftest for the bulk delete and cover cases with
> > veth, vlan, vrf, dummy, bridge, ...
> >
>
> BTW, delete of a netdev clears out neighbor entries, network addresses,
> routes, hardware updates, etc. with lots of notifications to userspace.
> Bulk delete of 1000s of netdevs is going to end up holding the rtnl for
> a "long" time. It would be good for the selftests to include a cases
> with lots of neighbor entries, routes, addresses.

Ack. I'll add such tests to v7. What numbers you have in mind for the
number of routes/neighbours etc? I suppose we don't want the tests to
run for extremely long times.