From owner-freebsd-hackers  Thu Jun 29 15:43:51 2000
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Date: Thu, 29 Jun 2000 15:43:44 -0700 (PDT)
From: Jin Guojun (DSD staff) <jin@george.lbl.gov>
Message-Id: <200006292243.e5TMhim19889@portnoy.lbl.gov>
To: hackers@freebsd.org
Subject: possible doing context switch between network and link layers?
Sender: owner-freebsd-hackers@FreeBSD.ORG
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Hi,

Try to control the NIC output, instead of dropping the packet, I would
like to do context switch on current sending process.  tsleep() seems not
to be a right mechanism for this purpose because it will panic in the kernel
wherever between the network and link layers the tsleep() is put -- e.g.

ether_output()
{
	...
	if (IF_QFULL)	{
		tsleep(m, PSOCK, "pause NIC", 1);
		if (IF_QFULL)
			DROP_Q;
	}
	...
}

Is there other context switch mechanism for this purpose? or
is it impossible to do the context switch at network and link layers?

	-Jin


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