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From:   Eric Dumazet <edumazet@google.com>
Date:   Wed, 13 Apr 2022 10:53:12 -0700
Message-ID: <CANn89iK=8Z2dznM_SVGtk3NsXu3PK_BOBnCOM2ZgFtKe-mBOyA@mail.gmail.com>
Subject: Re: [PATCH net] rxrpc: Restore removed timer deletion
To:     David Howells <dhowells@redhat.com>
Cc:     netdev@vger.kernel.org, Marc Dionne <marc.dionne@auristor.com>,
        linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org
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On Wed, Apr 13, 2022 at 10:41 AM David Howells <dhowells@redhat.com> wrote:
>
> Eric Dumazet <edumazet@google.com> wrote:
>
> > ok... so we have a timer and a work queue, both activating each other
> > in kind of a ping pong ?
>
> Yes.  I want to emit regular keepalive pokes.
>
> > Any particular reason not using delayed works ?
>
> Because there's a race between starting the keepalive timer when a new peer is
> added and when the keepalive worker is resetting the timer for the next peer
> in the list.  This is why I'm using timer_reduce().  delayed_work doesn't
> currently have such a facility.  It's not simple to add because
> try_to_grab_pending() as called from mod_delayed_work_on() cancels the timer -
> which is not what I want it to do.
>

SGTM, thanks !

Reviewed-by: Eric Dumazet <edumazet@google.com>