From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: gso: Attempt to handle mega-GRO packets Date: Wed, 06 Nov 2013 07:05:41 -0800 Message-ID: <1383750341.4291.166.camel@edumazet-glaptop2.roam.corp.google.com> References: <20131103163103.GA18894@gondor.apana.org.au> <1383499603.4291.71.camel@edumazet-glaptop2.roam.corp.google.com> <20131104041108.GA22823@gondor.apana.org.au> <20131106013038.GA14894@gondor.apana.org.au> <1383702347.4291.152.camel@edumazet-glaptop2.roam.corp.google.com> <20131106040717.GA15711@gondor.apana.org.au> <1383711785.4291.156.camel@edumazet-glaptop2.roam.corp.google.com> <20131106042858.GA15745@gondor.apana.org.au> <1383715222.4291.158.camel@edumazet-glaptop2.roam.corp.google.com> <20131106080425.GA17556@gondor.apana.org.au> <20131106081638.GA17665@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Ben Hutchings , David Miller , christoph.paasch@uclouvain.be, netdev@vger.kernel.org, hkchu@google.com, mwdalton@google.com, mst@redhat.com To: Herbert Xu Return-path: Received: from mail-pd0-f174.google.com ([209.85.192.174]:62313 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932252Ab3KFPFn (ORCPT ); Wed, 6 Nov 2013 10:05:43 -0500 Received: by mail-pd0-f174.google.com with SMTP id z10so10319569pdj.33 for ; Wed, 06 Nov 2013 07:05:43 -0800 (PST) In-Reply-To: <20131106081638.GA17665@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 2013-11-06 at 16:16 +0800, Herbert Xu wrote: > Instead of using perfectly sane 4K pages per frag to store guest to > guest traffic, we now end up using 1.5K frags, which that's why you > end up having to use the frag_list, WTF? Sure, if your host has infinite amount of memory, we can remove all the silly and expensive and bore some checks we added in the stack against skb->truesize. And yes, network stack will be faster. But in real life, we have memory constraints.