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From: nicolas prochazka <prochazka.nicolas@gmail.com>
Date: Wed, 14 Jun 2017 09:52:13 +0200
Message-ID: <CADdae-h6BO4=tGU=QrYHWr4iW7MgMzk2ukw9jes33WEoxAF1Gw@mail.gmail.com>
Subject: Re: multiple wireguard interface and kworker ressources
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
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hello,
after create of wg interface, kworker thread does not return to a
normal state in my case,
kernel thread continues to consume a lot of cpu .
I must delete wireguard interface to kworker decrease.

Nicolas

2017-06-13 23:47 GMT+02:00 Jason A. Donenfeld <Jason@zx2c4.com>:
> Hi Nicolas,
>
> It looks to me like some resources are indeed expended in adding those
> interfaces. Not that much that would be problematic -- are you seeing
> a problematic case? -- but still a non-trivial amount.
>
> I tracked it down to WireGuard's instantiation of xt_hashlimit, which
> does some ugly vmalloc, and it's call into the power state
> notification system, which uses a naive O(n) algorithm for insertion.
> I might have a way of amortizing on module insertion, which would
> speed things up. But I wonder -- what is the practical detriment of
> spending a few extra cycles on `ip link add`? What's your use case
> where this would actually be a problem?
>
> Thanks,
> Jason