netdev - [RFC] NAPI behavior when (work

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Date:	Wed, 4 Feb 2015 15:22:38 +0200
From:	Vladimir Kondratiev <QCA_vkondrat@....qualcomm.com>
To:	<netdev@...r.kernel.org>
CC:	"David S. Miller" <davem@...emloft.net>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Eric Dumazet <edumazet@...gle.com>,
	Tom Herbert <therbert@...gle.com>,
	Vlad Yasevich <vyasevic@...hat.com>,
	Jiri Pirko <jiri@...nulli.us>,
	John Fastabend <john.fastabend@...il.com>,
	Joe Perches <joe@...ches.com>
Subject: [RFC] NAPI behavior when (work < weight)

Hi

I am observing that if driver does not calls napi_complete() when
less than full budget consumed, various strange things happen.

For example, if driver going to napi_disable(), it may wait forever
in the loop:

	while (test_and_set_bit(NAPI_STATE_SCHED, &n->state))
		msleep(1);

if last NAPI consumed less then full budget, because bit
NAPI_STATE_SCHED never cleared.

Is it expected that driver calls napi_complete() when less than full
budget consumed? Documentation does not say so.

What is intended behavior in case above?

Thanks, Vladimir 
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