From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 18/29] netfilter: notify about NF_QUEUE vs emergency skbs Date: Sat, 24 Feb 2007 17:55:49 +0100 Message-ID: <1172336149.28579.11.camel@lappy> References: <20070221144304.512721000@taijtu.programming.kicks-ass.net> <20070221144843.299254000@taijtu.programming.kicks-ass.net> <45E05954.8050204@trash.net> <1172332010.28579.6.camel@lappy> <45E064FF.8010000@trash.net> <1172333937.6374.47.camel@twins> <45E06A86.2060408@trash.net> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, Trond Myklebust , Thomas Graf , David Miller To: Patrick McHardy Return-path: Received: from amsfep19-int.chello.nl ([62.179.120.14]:64787 "EHLO amsfep19-int.chello.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933519AbXBXQz7 (ORCPT ); Sat, 24 Feb 2007 11:55:59 -0500 In-Reply-To: <45E06A86.2060408@trash.net> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Sat, 2007-02-24 at 17:40 +0100, Patrick McHardy wrote: > Peter Zijlstra wrote: > > On Sat, 2007-02-24 at 17:17 +0100, Patrick McHardy wrote: > > > > > >>I don't really see why > >>queueing is special though, dropping the packets in the ruleset > >>will break things just as well, as will routing them to a blackhole. > >>I guess the user just needs to be smart enough not to do this. > > > > > > Its user-space and no emergency packet may rely on user-space because it > > most likely is needed to maintain user-space. > > I believe I might have misunderstood the intention of this patch. > > Assuming the user is smart enough not to queue packets destined > to a SOCK_VMIO socket, are you worried about unrelated packets > allocated from the emergency reserve not getting freed fast > enough because they're sitting in a queue? In that case simply > dropping the packets would be fine I guess. OK, that sounds good. I shall make NF_QUEUE a black hole for emergency packets. Alas, that leaves no way to warn a user about a SOCK_VMIO bound packet treated this way, since, as you said, that is unknown at this point in the chain. Thanks, Peter