From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [Patch v2] skbuff: Hide GFP_ATOMIC page allocation failures for dropped packets Date: Mon, 27 May 2013 23:04:14 -0700 Message-ID: <1369721054.3301.531.camel@edumazet-glaptop> References: <1369599557-22677-1-git-send-email-atomlin@redhat.com> <51A39A3F.8080903@redhat.com> <1369693520.3301.477.camel@edumazet-glaptop> <1369715506.2034.30.camel@joe-AO722> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Rik van Riel , atomlin@redhat.com, netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, pshelar@nicira.com, mst@redhat.com, alexander.h.duyck@intel.com, aquini@redhat.com, sergei.shtylyov@cogentembedded.com, linux-kernel@vger.kernel.org To: Joe Perches Return-path: Received: from mail-pb0-f51.google.com ([209.85.160.51]:35187 "EHLO mail-pb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932969Ab3E1GER (ORCPT ); Tue, 28 May 2013 02:04:17 -0400 In-Reply-To: <1369715506.2034.30.camel@joe-AO722> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2013-05-27 at 21:31 -0700, Joe Perches wrote: > I think the __alloc_skb alloc failure message is ok, > but maybe there shouldn't be something "scary" like > a dump_stack. > > Maybe this site should use a trivial debug error > message like below instead. > --- Oh well. If dump_stack are scary, they are scary for every k[mz]alloc() users, not only __alloc_skb_alloc() I just said : Please do not add GFP_NOWARN to thousand of call sites, and you suggest adding more code in network fast path. (???) This is not a trivial code, we are speaking of a very sensitive one. Let mm guys explain in what cases a full stack trace is nice to have, and in what cases its useless. An heuristic should be defined in mm tree for that, and not spread everywhere. There must be a reason GFP_NOWARN is seldom used in the kernel, even if most callers are able to recover properly from a failed memory allocation.