From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: GFP_ATOMIC page allocation failures. Date: Wed, 2 Apr 2008 10:33:55 -0700 Message-ID: <20080402103355.77ef22ff.akpm@linux-foundation.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> <47F3C0A8.9090300@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Chris Snook , Dave Jones , Nick Piggin , Linux Kernel , NetDev , David Miller , Linus Torvalds To: Jeff Garzik Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:54288 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756072AbYDBRiI (ORCPT ); Wed, 2 Apr 2008 13:38:08 -0400 In-Reply-To: <47F3C0A8.9090300@garzik.org> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 02 Apr 2008 13:21:44 -0400 Jeff Garzik wrote: > 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 > > > > 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). > After you've read Nick's comments (which I pray you have not), and after you've convinced us and yourself of their wrongness, you might like to consider adding a __GFP_NOWARN to netdev_alloc_skb().