From: Jakub Kicinski <kuba@kernel.org>
To: Eric Dumazet <edumazet@google.com>
Cc: davem@davemloft.net, netdev@vger.kernel.org, pabeni@redhat.com,
Roman Gushchin <roman.gushchin@linux.dev>,
leitao@debian.org, shemminger@linux.foundation.org
Subject: Re: [PATCH net] net: don't let netpoll invoke NAPI if in xmit context
Date: Thu, 30 Mar 2023 20:23:33 -0700 [thread overview]
Message-ID: <20230330202333.108dadd9@kernel.org> (raw)
In-Reply-To: <CANn89iL99-uzrktK=hKLrmoWhhqCnH5rNUC9K4W9cOs+CQrbdA@mail.gmail.com>
On Fri, 31 Mar 2023 04:41:23 +0200 Eric Dumazet wrote:
> Note that we update WRITE_ONCE(txq->xmit_lock_owner, cpu) _after_
> spin_lock(&txq->_xmit_lock);
>
> So there is a tiny window I think, for missing that we got the
> spinlock, but I do not see how to avoid it without excessive cost.
Ugh, true. Hopefully the chances of taking an IRQ which tries to print
something between those two instructions are fairly low.
I was considering using dev_recursion_level() but AFAICT we don't
currently bump it when dequeuing from the qdisc..
next prev parent reply other threads:[~2023-03-31 3:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-31 2:21 [PATCH net] net: don't let netpoll invoke NAPI if in xmit context Jakub Kicinski
2023-03-31 2:41 ` Eric Dumazet
2023-03-31 3:23 ` Jakub Kicinski [this message]
2023-03-31 3:34 ` Eric Dumazet
2023-04-02 12:30 ` patchwork-bot+netdevbpf
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