From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff Garzik <jeff@garzik.org>
Subject: Re: GFP_ATOMIC page allocation failures.
Date: Wed, 02 Apr 2008 13:21:44 -0400
Message-ID: <47F3C0A8.9090300@garzik.org>
References: <20080401235609.GA6947@codemonkey.org.uk>	<200804021228.16875.nickpiggin@yahoo.com.au>	<20080402013551.GA8361@codemonkey.org.uk>	<47F32789.2070703@redhat.com> <20080402005646.f8df1c1b.akpm@linux-foundation.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Cc: Chris Snook <csnook@redhat.com>,
	Dave Jones <davej@codemonkey.org.uk>,
	Nick Piggin <nickpiggin@yahoo.com.au>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	NetDev <netdev@vger.kernel.org>,
	David Miller <davem@davemloft.net>,
	Linus Torvalds <torvalds@linux-foundation.org>
To: Andrew Morton <akpm@linux-foundation.org>
Return-path: <netdev-owner@vger.kernel.org>
Received: from srv5.dvmed.net ([207.36.208.214]:57910 "EHLO mail.dvmed.net"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1756004AbYDBRWL (ORCPT <rfc822;netdev@vger.kernel.org>);
	Wed, 2 Apr 2008 13:22:11 -0400
In-Reply-To: <20080402005646.f8df1c1b.akpm@linux-foundation.org>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

Andrew Morton wrote:
> The appropriate thing to do here is to convert known-good drivers (such as
> e1000[e]) to use __GFP_NOWARN.
> 
> Unfortunately netdev_alloc_skb() went and assumed GFP_ATOMIC, but I guess
> we can dive below the covers and use __netdev_alloc_skb():
> 
> 
> 
> From: Andrew Morton <akpm@linux-foundation.org>
> 
> We get rather a lot of reports of page allocation warnings coming out of
> e1000.  But this driver is know to handle them properly so let's suppress
> them.


Do you people hear what you're saying???

I respectfully but strongly disagree with this.

We do __not__ need a whitelist (__GFP_NOWARN) of drivers that handle 
allocation failures properly.  That's a long list, a maintenance 
nightmare, and it is punishing good behavior.

It has been true for over a decade that allocations should be checked 
for NULL, and GFP_ATOMIC allocations MUST be checked for NULL.

Let's not crap all over good drivers, because a few bad apples don't 
have the proper checks.

Or at the very least, this TOTALLY BOGUS spew from working drivers 
should not be foisted upon users.  Every time a working driver complains 
about this -- as in the examples here -- the value of the warning 
decreases to noise.

And the solution to noise is not _more noise_ (adding 'nowarn' to every 
damn driver in the kernel).

	Jeff